css-fonts/Fonts.html@4fb97110e8dc
css-fonts/Fonts.html
Fri, 31 May 2013 14:54:16 +0900
- author
- John Daggett <jdaggett@mozilla.com>
- date
- Fri, 31 May 2013 14:54:16 +0900
- changeset 8312
- 4fb97110e8dc
- parent 8311
- 35cf30e4d0ec
- child 8313
- f7084873c602
- permissions
- -rw-r--r--
[css-fonts] fixups based on font-variant-*, minor comments II (but I'm not hyphenating subproperty dammit)
1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
4 <html lang=en>
5 <head><meta content="text/html;charset=utf-8" http-equiv=Content-Type>
7 <title>CSS Fonts Module Level 3</title>
8 <!--
9 FIXME when publishing: copy the current default.css and link to
10 "default.css" rather than "../default.css"
11 -->
12 <link href="../default.css" rel=stylesheet type="text/css">
13 <link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
14 <!-- I'm just experimenting here, don't get your bee in a bonnet -->
15 <script src="http://use.typekit.com/xon2bky.js"
16 type="text/javascript"></script>
17 <script type="text/javascript">try{Typekit.load();}catch(e){}</script>
19 <style type="text/css">
21 body, th, td, h1, h2, h3, h4, h5, h6 {
22 font-family: "myriad-pro", sans-serif !important;
23 }
25 body {
26 padding: 2em 70px 2em 70px;
27 }
29 p + p, p.mtb {
30 margin-top: 0.8em;
31 text-indent: 0px;
32 }
34 #bolderlighter {
35 width: 40%;
36 }
38 #bolderlighter th {
39 text-align: center;
40 }
42 #fontformats td, #eventhandlers td, #fontformats th, #eventhandlers th {
43 padding-right: 2em;
44 text-align: left;
45 }
47 dd {
48 margin-bottom: 1em;
49 }
51 #authors dd {
52 margin-bottom: 0;
53 }
55 #fontstylematchingalg {
56 list-style-type: lower-alpha;
57 }
59 #fontmatchingalg ul, #fontmatchingalg ol {
60 margin-top: 0.8em;
61 }
63 #fontmatchingalg li + li {
64 margin-top: 0.8em;
65 }
67 div.example {
68 padding: 1em;
69 margin-top: 1em;
70 }
72 div.example + div.example {
73 margin-top: 2em;
74 }
76 div.figure {
77 page-break-inside: avoid;
78 }
80 pre.prod { white-space: pre-wrap; margin: 1em 0 1em 2em }
82 div.featex {
83 width: 700px;
84 }
86 div.featex img {
87 margin: auto;
88 display: block;
89 }
91 span.tag {
92 font-family: monospace;
93 font-size: 120%;
94 }
96 ol ol {
97 list-style-type: lower-alpha;
98 }
100 .idl-code {
101 font-weight: bold;
102 color: #c50;
103 }
104 </style>
105 <link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
106 type="text/css">
108 <body>
109 <div class=head> <!--begin-logo-->
110 <p><a href="http://www.w3.org/"><img alt=W3C height=48
111 src="http://www.w3.org/Icons/w3c_home" width=72></a> <!--end-logo-->
113 <h1>CSS Fonts Module Level 3</h1>
115 <h2 class="no-num no-toc" id=editors-draft-31-may-2013>Editor's Draft 31
116 May 2013</h2>
118 <dl id=authors>
119 <dt>This version:
121 <dd><a
122 href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>
123 <!-- <dd><a href="http://www.w3.org/TR/2013/ED-css3-fonts-20130531/">http://www.w3.org/TR/2013/ED-css3-fonts-20130531/</a> -->
126 <dt>Latest version:
128 <dd><a
129 href="http://www.w3.org/TR/css3-fonts/">http://www.w3.org/TR/css3-fonts/</a>
131 <dt>Latest editor's draft:
133 <dd><a
134 href="http://dev.w3.org/csswg/css-fonts/">http://dev.w3.org/csswg/css-fonts/</a>
135 (<a
136 href="https://dvcs.w3.org/hg/csswg/log/tip/css-fonts/Fonts.html">change
137 log</a>)
139 <dt>Previous version:
141 <dd><a
142 href="http://www.w3.org/TR/2013/WD-css3-fonts-20130212/">http://www.w3.org/TR/2013/WD-css3-fonts-20130212/</a>
144 <dt>Issues List:
146 <dd><a href="http://www.w3.org/Style/CSS/Tracker/products/18">CSS3 Fonts
147 issues in Tracker</a>
149 <dd><a
150 href="https://www.w3.org/Bugs/Public/buglist.cgi?query_format=advanced&product=CSS&component=Fonts&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED">CSS3
151 Fonts issues in Bugzilla</a>
153 <dt>Discussion:
155 <dd><a
156 href="mailto:www-style@w3.org?subject=%5Bcss-fonts%5D%20feedback">www-style@w3.org</a>
157 with subject line “<kbd>[css-fonts] <var>… message topic
158 …</var></kbd>” (<a
159 href="http://lists.w3.org/Archives/Public/www-style/"
160 rel=discussion>archives</a>)
162 <dt>Editor:
164 <dd><a href="mailto:jdaggett@mozilla.com">John Daggett (Mozilla)</a>
165 </dl>
166 <!--begin-copyright-->
167 <p class=copyright><a
168 href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"
169 rel=license>Copyright</a> © 2013 <a href="http://www.w3.org/"><abbr
170 title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a
171 href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of
172 Technology">MIT</abbr></a>, <a href="http://www.ercim.eu/"><abbr
173 title="European Research Consortium for Informatics and
174 Mathematics">ERCIM</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>,
175 <a href="http://ev.buaa.edu.cn/">Beihang</a>), All Rights Reserved. W3C
176 <a
177 href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
178 <a
179 href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a>
180 and <a
181 href="http://www.w3.org/Consortium/Legal/copyright-documents">document
182 use</a> rules apply.</p>
183 <!--end-copyright-->
184 <hr title="Separator for header">
185 </div>
187 <h2 class="no-num no-toc" id=abstract>Abstract</h2>
189 <p>This CSS3 module describes how font properties are specified and how
190 font resources are loaded dynamically. The contents of this specification
191 are a consolidation of content previously divided into <a
192 href="http://www.w3.org/TR/2002/WD-css3-fonts-20020802/">CSS3 Fonts</a>
193 and <a href="http://www.w3.org/TR/2002/WD-css3-webfonts-20020802/">CSS3
194 Web Fonts</a> modules. The description of font load events was moved into
195 the <a href="http://dev.w3.org/csswg/css3-font-load-events/">CSS3 Font
196 Load Events</a> module.
198 <h2 class="no-num no-toc" id=status>Status of this document</h2>
199 <!--begin-status-->
201 <p>This is a public copy of the editors' draft. It is provided for
202 discussion only and may change at any moment. Its publication here does
203 not imply endorsement of its contents by W3C. Don't cite this document
204 other than as work in progress.
206 <p>The (<a
207 href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
208 mailing list <a
209 href="mailto:www-style@w3.org?Subject=%5Bcss3-fonts%5D%20PUT%20SUBJECT%20HERE">
210 www-style@w3.org</a> (see <a
211 href="http://www.w3.org/Mail/Request">instructions</a>) is preferred for
212 discussion of this specification. When sending e-mail, please put the text
213 “css3-fonts” in the subject, preferably like this:
214 “[<!---->css3-fonts<!---->] <em>…summary of comment…</em>”
216 <p>This document was produced by the <a
217 href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
218 the <a href="http://www.w3.org/Style/">Style Activity</a>).
220 <p>This document was produced by a group operating under the <a
221 href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
222 2004 W3C Patent Policy</a>. W3C maintains a <a
223 href="http://www.w3.org/2004/01/pp-impl/32061/status"
224 rel=disclosure>public list of any patent disclosures</a> made in
225 connection with the deliverables of the group; that page also includes
226 instructions for disclosing a patent. An individual who has actual
227 knowledge of a patent which the individual believes contains <a
228 href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
229 Claim(s)</a> must disclose the information in accordance with <a
230 href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
231 6 of the W3C Patent Policy</a>.</p>
232 <!--end-status-->
233 <!--
234 <h3 class="no-num no-toc" id="atrisk">Features at risk</h3>
236 <p>The following features are at risk and may be removed when exiting CR:</p>
238 <ul>
239 </ul>
240 -->
242 <h2 class="no-num no-toc" id=contents>Table of contents</h2>
243 <!--begin-toc-->
245 <ul class=toc>
246 <li><a href="#introduction"><span class=secno>1 </span>Introduction</a>
248 <li><a href="#typography-background"><span class=secno>2 </span>Typography
249 Background</a>
251 <li><a href="#basic-font-props"><span class=secno>3 </span>Basic Font
252 Properties</a>
253 <ul class=toc>
254 <li><a href="#font-family-prop"><span class=secno>3.1 </span>Font
255 family: the font-family property</a>
256 <ul class=toc>
257 <li><a href="#generic-font-families"><span class=secno>3.1.1
258 </span>Generic font families</a>
259 </ul>
261 <li><a href="#font-weight-prop"><span class=secno>3.2 </span>Font
262 weight: the font-weight property</a>
264 <li><a href="#font-stretch-prop"><span class=secno>3.3 </span>Font
265 width: the font-stretch property</a>
267 <li><a href="#font-style-prop"><span class=secno>3.4 </span>Font style:
268 the font-style property</a>
270 <li><a href="#font-size-prop"><span class=secno>3.5 </span>Font size:
271 the font-size property</a>
273 <li><a href="#font-size-adjust-prop"><span class=secno>3.6
274 </span>Relative sizing: the font-size-adjust property</a>
276 <li><a href="#font-prop"><span class=secno>3.7 </span>Shorthand font
277 property: the font property</a>
279 <li><a href="#font-synthesis-prop"><span class=secno>3.8
280 </span>Controlling synthetic faces: the font-synthesis property</a>
281 </ul>
283 <li><a href="#font-resources"><span class=secno>4 </span>Font
284 Resources</a>
285 <ul class=toc>
286 <li><a href="#font-face-rule"><span class=secno>4.1 </span>The
287 <code>@font-face</code> rule</a>
289 <li><a href="#font-family-desc"><span class=secno>4.2 </span>Font
290 family: the font-family descriptor</a>
292 <li><a href="#src-desc"><span class=secno>4.3 </span>Font reference: the
293 src descriptor</a>
295 <li><a href="#font-prop-desc"><span class=secno>4.4 </span>Font property
296 descriptors: the font-style, font-weight, font-stretch descriptors</a>
298 <li><a href="#unicode-range-desc"><span class=secno>4.5 </span>Character
299 range: the unicode-range descriptor</a>
301 <li><a href="#composite-fonts"><span class=secno>4.6 </span>Using
302 character ranges to define composite fonts</a>
304 <li><a href="#font-rend-desc"><span class=secno>4.7 </span>Font
305 features: the font-variant and font-feature-settings descriptors</a>
307 <li><a href="#font-face-loading"><span class=secno>4.8 </span>Font
308 loading guidelines</a>
310 <li><a href="#same-origin-restriction"><span class=secno>4.9
311 </span>Same-origin restriction for fonts</a>
312 <ul class=toc>
313 <li><a href="#default-same-origin-restriction"><span class=secno>4.9.1
314 </span>Default same-origin restriction</a>
316 <li><a href="#allowing-cross-origin-font-loading"><span
317 class=secno>4.9.2 </span>Allowing cross-origin font loading</a>
318 </ul>
319 </ul>
321 <li><a href="#font-matching-algorithm"><span class=secno>5 </span>Font
322 Matching Algorithm</a>
323 <ul class=toc>
324 <li><a href="#font-family-casing"><span class=secno>5.1 </span>Case
325 sensitivity of font family names</a>
327 <li><a href="#font-style-matching"><span class=secno>5.2 </span>Matching
328 font styles</a>
330 <li><a href="#cluster-matching"><span class=secno>5.3 </span>Cluster
331 matching</a>
333 <li><a href="#char-handling-issues"><span class=secno>5.4
334 </span>Character handling issues</a>
336 <li><a href="#font-matching-changes"><span class=secno>5.5 </span>Font
337 matching changes since CSS 2.1</a>
339 <li><a href="#font-matching-examples"><span class=secno>5.6 </span>Font
340 matching examples</a>
341 </ul>
343 <li><a href="#font-rend-props"><span class=secno>6 </span>Font Feature
344 Properties</a>
345 <ul class=toc>
346 <li><a href="#glyph-selection-positioning"><span class=secno>6.1
347 </span>Glyph selection and positioning</a>
349 <li><a href="#language-specific-support"><span class=secno>6.2
350 </span>Language-specific display</a>
352 <li><a href="#font-kerning-prop"><span class=secno>6.3 </span>Kerning:
353 the font-kerning property</a>
355 <li><a href="#font-variant-ligatures-prop"><span class=secno>6.4
356 </span>Ligatures: the font-variant-ligatures property</a>
358 <li><a href="#font-variant-position-prop"><span class=secno>6.5
359 </span>Subscript and superscript forms: the font-variant-position
360 property</a>
362 <li><a href="#font-variant-caps-prop"><span class=secno>6.6
363 </span>Capitalization: the font-variant-caps property</a>
365 <li><a href="#font-variant-numeric-prop"><span class=secno>6.7
366 </span>Numerical formatting: the font-variant-numeric property</a>
368 <li><a href="#font-variant-alternates-prop"><span class=secno>6.8
369 </span>Alternates and swashes: the font-variant-alternates property</a>
372 <li><a href="#font-feature-values"><span class=secno>6.9 </span>Defining
373 font specific alternates: the <code>@font-feature-values</code>
374 rule</a>
376 <li><a href="#font-variant-east-asian-prop"><span class=secno>6.10
377 </span>East Asian text rendering: the font-variant-east-asian
378 property</a>
380 <li><a href="#font-variant-prop"><span class=secno>6.11 </span>Overall
381 shorthand for font rendering: the font-variant property</a>
383 <li><a href="#font-feature-settings-prop"><span class=secno>6.12
384 </span>Low-level font feature settings control: the
385 font-feature-settings property</a>
387 <li><a href="#font-language-override-prop"><span class=secno>6.13
388 </span>Font language override: the font-language-override property</a>
389 </ul>
391 <li><a href="#font-feature-resolution"><span class=secno>7 </span>Font
392 Feature Resolution </a>
393 <ul class=toc>
394 <li><a href="#default-features"><span class=secno>7.1 </span>Default
395 features</a>
397 <li><a href="#feature-precedence"><span class=secno>7.2 </span>Feature
398 precedence</a>
400 <li><a href="#feature-precedence-examples"><span class=secno>7.3
401 </span>Feature precedence examples</a>
402 </ul>
404 <li><a href="#object-model"><span class=secno>8 </span>Object Model</a>
405 <ul class=toc>
406 <li><a href="#om-fontface"><span class=secno>8.1 </span>The
407 <code>CSSFontFaceRule</code> interface</a>
409 <li><a href="#om-fontfeaturevalues"><span class=secno>8.2 </span>The
410 <code>CSSFontFeatureValuesRule</code> interface</a>
411 </ul>
413 <li class=no-num><a href="#platform-props-to-css">Appendix A: Mapping
414 platform font properties to CSS properties</a>
416 <li class=no-num><a href="#ch-ch-ch-changes">Changes</a>
417 <ul class=toc>
418 <li class=no-num><a href="#recent-changes"> Changes from the February
419 2013 CSS3 Fonts Working Draft</a>
420 </ul>
422 <li class=no-num><a href="#acknowledgments">Acknowledgments</a>
424 <li class=no-num><a href="#conformance"> Conformance</a>
425 <ul class=toc>
426 <li class=no-num><a href="#conventions"> Document Conventions</a>
428 <li class=no-num><a href="#conformance-classes"> Conformance Classes</a>
431 <li class=no-num><a href="#partial"> Partial Implementations</a>
433 <li class=no-num><a href="#experimental"> Experimental
434 Implementations</a>
436 <li class=no-num><a href="#testing"> Non-Experimental
437 Implementations</a>
438 </ul>
440 <li class=no-num><a href="#references">References</a>
441 <ul class=toc>
442 <li class=no-num><a href="#normative-references">Normative
443 References</a>
445 <li class=no-num><a href="#other-references">Other References</a>
446 </ul>
448 <li class=no-num><a href="#index">Index</a>
450 <li class=no-num><a href="#property-index">Property index</a>
451 </ul>
452 <!--end-toc-->
454 <h2 id=introduction><span class=secno>1 </span>Introduction</h2>
456 <p>A font provides a resource containing the visual representation of
457 characters. At the simplest level it contains information that maps
458 character codes to shapes (called glyphs) that represent these characters.
459 Fonts sharing a common design style are commonly grouped into font
460 families classified by a set of standard font properties. Within a family,
461 the shape displayed for a given character can vary by stroke weight, slant
462 or relative width, among others. An individual font face is described by a
463 unique combination of these properties. For a given range of text, CSS
464 font properties are used to select a font family and a specific font face
465 within that family to be used when rendering that text. As a simple
466 example, to use the bold form of Helvetica one could use:
468 <pre>body {
469 font-family: Helvetica;
470 font-weight: bold;
471 }</pre>
473 <p>Font resources may be installed locally on the system on which a user
474 agent is running or downloadable. For local font resources descriptive
475 information can be obtained directly from the font resource. For
476 downloadable font resources (sometimes referred to as web fonts), the
477 descriptive information is included with the reference to the font
478 resource.
480 <p>Families of fonts typically don't contain a single face for each
481 possible variation of font properties. The CSS font selection mechanism
482 describes how to match a given set of CSS font properties to a single font
483 face.
485 <h2 id=typography-background><span class=secno>2 </span>Typography
486 Background</h2>
488 <p><em>This section is non-normative.</em>
490 <p> Typographic traditions vary across the globe, so there is no unique way
491 to classify all fonts across languages and cultures. For even common Latin
492 letters, wide variations are possible:
494 <div class=figure><img alt="variations in glyphs for a single character"
495 src=aaaaaa.png>
496 <p class=caption>One character, many glyph variations
497 </div>
499 <p>Differences in the anatomy of letterforms is one way to distinguish
500 fonts. For Latin fonts, flourishes at the ends of a character's main
501 strokes, or serifs, can distinguish a font from those without. Similar
502 comparisons exist in non-Latin fonts between fonts with tapered strokes
503 and those using primarily uniform strokes:
505 <div class=figure><img alt="serif vs. non-serifs" src=serifvssansserif.png>
506 <p class=caption>Letterforms with and without serifs
507 </div>
509 <div class=figure><img alt="serif vs. non-serifs for japanese"
510 src=minchovsgothic.png>
511 <p class=caption>Similar groupings for Japanese typefaces
512 </div>
514 <p>Fonts contain letterforms and the data needed to map characters to these
515 letterforms. Often this may be a simple one-to-one mapping, but more
516 complex mappings are also possible. The use of combining diacritic marks
517 creates many variations for an underlying letterform:
519 <div class=figure><img alt="diacritic marks" src=aaaaaa-diacritics.png>
520 <p class=caption>Variations with diacritic marks
521 </div>
523 <p>A sequence of characters can be represented by a single glyph known as a
524 ligature:
526 <div class=figure><img alt="example of a fi ligature"
527 src=final-ligature.png>
528 <p class=caption>Ligature example
529 </div>
531 <p>Visual transformations based on textual context are often stylistic
532 option in European languages. They are required to correctly render
533 languages like Arabic, the lam and alef characters below <em>must</em> be
534 combined when they exist in sequence:
536 <div class=figure><img alt="lam alef ligature" src=lamaleflig.png>
537 <p class=caption>Required Arabic ligature
538 </div>
540 <p>The relative complexity of these shaping transformations requires
541 additional data within the font.
543 <p>Sets of font faces with various stylistic variations are often grouped
544 together into font families. In the simplest case a regular face is
545 supplemented with bold and italic faces, but much more extensive groupings
546 are possible. Variations in the thickness of letterform strokes, the <dfn
547 id=weight>weight</dfn>, and the overall proportions of the letterform, the
548 <dfn id=width>width</dfn>, are most common. In the example below, each
549 letter uses a different font face within the Univers font family. The
550 width used increases from top to bottom and the weight increases from left
551 to right:
553 <div class=figure><img alt="various width and weight variations within a
554 single family" src=weightwidthvariations.png>
555 <p class=caption>Weight and width variations within a single font family
556 </div>
558 <p>Creating fonts that support multiple scripts is a difficult task;
559 designers need to understand the cultural traditions surrounding the use
560 of type in different scripts and come up with letterforms that somehow
561 share a common theme. Many languages often share a common script and each
562 of these languages may have noticeable stylistic differences. For example,
563 the Arabic script is shared by Persian and Urdu and Cyrillic is used with
564 many languages, not just Russian.
566 <p>The <a href="#character-map"><em>character map</em></a> of a font
567 defines the mapping of characters to glyphs for that font. If a document
568 contains characters not supported by the <a href="#character-map"><em
569 title="character map">character maps</em></a> of the fonts contained in a
570 font family list, a user agent may use a system font fallback procedure to
571 locate an appropriate font that does. If no appropriate font can be found,
572 some form of "missing glyph" character will be rendered by the user agent.
573 System fallback can occur when the specified list of font families does
574 not include a font that supports a given character.
576 <p>Although the <a href="#character-map"><em>character map</em></a> of a
577 font maps a given character to a glyph for that character, modern font
578 technologies such as OpenType and AAT (Apple Advanced Typography) provide
579 ways of mapping a character to different glyphs based upon feature
580 settings. Fonts in these formats allow these features to be embedded in
581 the font itself and controlled by applications. Common typographic
582 features which can be specified this way include ligatures, swashes,
583 contextual alternates, proportional and tabular figures, and automatic
584 fractions, to list just a few. For a visual overview of OpenType features,
585 see the <a href="#OPENTYPE-FONT-GUIDE"
586 rel=biblioentry>[OPENTYPE-FONT-GUIDE]<!--{{OPENTYPE-FONT-GUIDE}}--></a>.
588 <h2 id=basic-font-props><span class=secno>3 </span>Basic Font Properties</h2>
590 <p>The particular font face used to render a character is determined by the
591 font family and other font properties that apply to a given element. This
592 structure allows settings to be varied independent of each other.</p>
593 <!-- prop: font-family -->
595 <h3 id=font-family-prop><span class=secno>3.1 </span>Font family: the <a
596 href="#propdef-font-family">font-family</a> property</h3>
598 <table class=propdef id=namefont-familyvalue-ltfamily-namegt-ltg>
599 <tbody>
600 <tr>
601 <td>Name:
603 <td><dfn id=propdef-font-family
604 title="font-family!!property">font-family</dfn>
606 <tr>
607 <td>Value:
609 <td>[ <a href="#family-name-value"><var><family-name></var></a> |
610 <a href="#generic-family-value"><var><generic-family></var></a> ]
611 #
613 <tr>
614 <td>Initial:
616 <td>depends on user agent
618 <tr>
619 <td>Applies to:
621 <td>all elements
623 <tr>
624 <td>Inherited:
626 <td>yes
628 <tr>
629 <td>Percentages:
631 <td>N/A
633 <tr>
634 <td>Media:
636 <td>visual
638 <tr>
639 <td>Computed value:
641 <td>as specified
643 <tr>
644 <td>Animatable:
646 <td>no
647 </table>
649 <p>This property specifies a prioritized list of font family names or
650 generic family names. A font family defines a set of faces that vary in
651 weight, width or slope. CSS uses the combination of a family name with
652 other style attributes to select an individual face. Using this selection
653 mechanism, rather than selecting a face via the style name as is often
654 done in design applications, allows some degree of regularity in textual
655 display when fallback occurs.
657 <p class=note>Designers should note that the CSS definition of font
658 attributes used for selection are explicitly not intended to define a font
659 taxonomy. A type designer's idea of a family may often extend to a set of
660 faces that vary along axes other than just the standard axes of weight,
661 width and slope. A family may extend to include both a set of serif faces
662 and a set of sans-serif faces or vary along axes that are unique to that
663 family. The CSS font selection mechanism merely provides a way to
664 determine the “closest” substitute when substitution is necessary.
666 <p>Unlike other CSS properties, component values are a comma-separated list
667 indicating alternatives. A user agent iterates through the list of family
668 names until it matches an available font that contains a glyph for the
669 character to be rendered. This allows for differences in available fonts
670 across platforms and for differences in the range of characters supported
671 by individual fonts.
673 <p>A font family name only specifies a name given to a set of font faces,
674 it does not specify an individual face. For example, given the
675 availability of the fonts below, Futura would match but Futura Medium
676 would not:
678 <div class=figure><img alt="family and face names"
679 src=familyvsfacename.png>
680 <p class=caption>Family and individual face names
681 </div>
683 <p>Consider the example below:
685 <div class=example>
686 <pre>body {
687 font-family: Helvetica, Verdana, sans-serif;
688 }</pre>
690 <p>If Helvetica is available it will be used when rendering. If neither
691 Helvetica nor Verdana is present, then the user-agent-defined sans serif
692 font will be used.</p>
693 </div>
695 <p>There are two types of font family names:
697 <dl>
698 <dt><dfn id=family-name-value><var><family-name></var></dfn>
700 <dd>The name of a font family of choice such as Helvetica or Verdana in
701 the previous example.
703 <dt><dfn id=generic-family-value><var><generic-family></var></dfn>
705 <dd> The following generic family keywords are defined: ‘<a
706 href="#serif"><code class=property>serif</code></a>’, ‘<a
707 href="#sans-serif"><code class=property>sans-serif</code></a>’, ‘<a
708 href="#cursive"><code class=property>cursive</code></a>’, ‘<a
709 href="#fantasy"><code class=property>fantasy</code></a>’, and ‘<a
710 href="#monospace"><code class=property>monospace</code></a>’. These
711 keywords can be used as a general fallback mechanism when an author's
712 desired font choices are not available. As keywords, they must not be
713 quoted. Authors are encouraged to append a generic font family as a last
714 alternative for improved robustness.
715 </dl>
717 <p>Font family names other than generic families must either be given
718 quoted as <a
719 href="//www.w3.org/TR/CSS21/syndata.html#strings">strings,</a> or unquoted
720 as a sequence of one or more <a
721 href="//www.w3.org/TR/CSS21/syndata.html#value-def-identifier">identifiers.</a>
722 This means most punctuation characters and digits at the start of each
723 token must be escaped in unquoted font family names.
725 <p>To illustrate this, the following declarations are invalid:
727 <pre>
728 font-family: Red/Black, sans-serif;
729 font-family: "Lucida" Grande, sans-serif;
730 font-family: Ahem!, sans-serif;
731 font-family: test@foo, sans-serif;
732 font-family: #POUND, sans-serif;
733 font-family: Hawaii 5-0, sans-serif;
734 </pre>
736 <p>If a sequence of identifiers is given as a font family name, the
737 computed value is the name converted to a string by joining all the
738 identifiers in the sequence by single spaces.
740 <p>To avoid mistakes in escaping, it is recommended to quote font family
741 names that contain white space, digits, or punctuation characters other
742 than hyphens:
744 <pre>
745 body { font-family: "New Century Schoolbook", serif }
747 <BODY STYLE="font-family: '21st Century', fantasy">
748 </pre>
750 <p>Font family <em>names</em> that happen to be the same as a keyword value
751 (‘<code class=property>inherit</code>’, ‘<a href="#serif"><code
752 class=property>serif</code></a>’, ‘<a href="#sans-serif"><code
753 class=property>sans-serif</code></a>’, ‘<a href="#monospace"><code
754 class=property>monospace</code></a>’, ‘<a href="#fantasy"><code
755 class=property>fantasy</code></a>’, and ‘<a href="#cursive"><code
756 class=property>cursive</code></a>’) must be quoted to prevent confusion
757 with the keywords with the same names. The keywords ‘<code
758 class=property>initial</code>’ and ‘<code
759 class=property>default</code>’ are reserved for future use and must also
760 be quoted when used as font names. UAs must not consider these keywords as
761 matching the <a
762 href="#family-name-value"><var><family-name></var></a> type.
764 <p>The precise way a set of fonts are grouped into font families varies
765 depending upon the platform font management API's. The Windows GDI API
766 only allows four faces to be grouped into a family while the DirectWrite
767 API and API's on OSX and other platforms support font families with a
768 variety of weights, widths and slopes (see <a
769 href="#platform-props-to-css">Appendix A</a> for more details).
771 <p>Some font formats allow fonts to carry multiple localizations of the
772 family name. User agents must recognize and correctly match all of these
773 names independent of the underlying platform localization, system API used
774 or document encoding:
776 <div class=figure><img alt="examples of localized family names"
777 src=localizedfamilynames.png>
778 <p class=caption>Localized family names
779 </div>
781 <h4 id=generic-font-families><span class=secno>3.1.1 </span>Generic font
782 families</h4>
784 <p>All five generic font families are defined to exist in all CSS
785 implementations (they need not necessarily map to five distinct actual
786 fonts). User agents should provide reasonable default choices for the
787 generic font families, which express the characteristics of each family as
788 well as possible within the limits allowed by the underlying technology.
789 User agents are encouraged to allow users to select alternative choices
790 for the generic fonts.
792 <h5 class="no-num no-toc"> <span class=index-def id=serif0 title="serif,
793 definition of"><a name=serif-def><dfn id=serif>serif</dfn></a></span></h5>
795 <p>Serif fonts represent the formal text style for a script. This often
796 means but is not limited to glyphs that have finishing strokes, flared or
797 tapering ends, or have actual serifed endings (including slab serifs).
798 Serif fonts are typically proportionately-spaced. They often display a
799 greater variation between thick and thin strokes than fonts from the ‘<a
800 href="#sans-serif"><code class=property>sans-serif</code></a>’ generic
801 font family. CSS uses the term ‘<a href="#serif"><code
802 class=property>serif</code></a>’ to apply to a font for any script,
803 although other names may be more familiar for particular scripts, such as
804 Mincho (Japanese), Sung, Song or Kai (Chinese), Batang (Korean). For
805 Arabic, the Naskh style would correspond to ‘<a href="#serif"><code
806 class=property>serif</code></a>’ more due to its typographic role rather
807 than its actual design style. Any font that is so described may be used to
808 represent the generic ‘<a href="#serif"><code
809 class=property>serif</code></a>’ family.
811 <div class=figure><img alt="sample serif fonts" src=serifexamples.png>
812 <p class=caption>Sample serif fonts
813 </div>
815 <h5 class="no-num no-toc"> <span class=index-def id=sans-serif0
816 title="sans-serif, definition of"> <a name=sans-serif-def><dfn
817 id=sans-serif>sans-serif</dfn></a></span></h5>
819 <p>Glyphs in sans-serif fonts, as the term is used in CSS, are generally
820 low contrast (vertical and horizontal stems have the close to the same
821 thickness) and have stroke endings that are plain -- without any flaring,
822 cross stroke, or other ornamentation. Sans-serif fonts are typically
823 proportionately-spaced. They often have little variation between thick and
824 thin strokes, compared to fonts from the ‘<a href="#serif"><code
825 class=property>serif</code></a>’ family. CSS uses the term ‘<a
826 href="#sans-serif"><code class=property>sans-serif</code></a>’ to apply
827 to a font for any script, although other names may be more familiar for
828 particular scripts, such as Gothic (Japanese), Hei (Chinese), or Gulim
829 (Korean). Any font that is so described may be used to represent the
830 generic ‘<a href="#sans-serif"><code
831 class=property>sans-serif</code></a>’ family.
833 <div class=figure><img alt="sample sans-serif fonts"
834 src=sansserifexamples.png>
835 <p class=caption>Sample sans-serif fonts
836 </div>
838 <h5 class="no-num no-toc"> <span class=index-def id=cursive0
839 title="cursive, definition of"> <a name=cursive-def><dfn
840 id=cursive>cursive</dfn></a></span></h5>
842 <p>Glyphs in cursive fonts generally use a more informal script style, and
843 the result looks more like handwritten pen or brush writing than printed
844 letterwork. CSS uses the term ‘<a href="#cursive"><code
845 class=property>cursive</code></a>’ to apply to a font for any script,
846 although other names such as Chancery, Brush, Swing and Script are also
847 used in font names.
849 <div class=figure><img alt="sample cursive fonts" src=cursiveexamples.png>
850 <p class=caption>Sample cursive fonts
851 </div>
853 <h5 class="no-num no-toc"> <span class=index-def id=fantasy0
854 title="fantasy, definition of"> <a name=fantasy-def><dfn
855 id=fantasy>fantasy</dfn></a></span></h5>
857 <p>Fantasy fonts are primarily decorative or expressive fonts that contain
858 playful representations of characters. These do not include Pi or Picture
859 fonts which do not represent actual characters.
861 <div class=figure><img alt="sample fantasy fonts" src=fantasyexamples.png>
862 <p class=caption>Sample fantasy fonts
863 </div>
865 <h5 class="no-num no-toc"> <span class=index-def id=monospace0
866 title="monospace, definition of"> <a name=monospace-def><dfn
867 id=monospace>monospace</dfn></a></span></h5>
869 <p>The sole criterion of a monospace font is that all glyphs have the same
870 fixed width. This is often used to render samples of computer code.
872 <div class=figure><img alt="sample monospace fonts"
873 src=monospaceexamples.png>
874 <p class=caption>Sample monospace fonts
875 </div>
876 <!-- prop: font-weight -->
878 <h3 id=font-weight-prop><span class=secno>3.2 </span>Font weight: the <a
879 href="#propdef-font-weight">font-weight</a> property</h3>
881 <table class=propdef id=namefont-weightvaluenormal-bold-bolder-l>
882 <tbody>
883 <tr>
884 <td>Name:
886 <td><dfn id=propdef-font-weight
887 title="font-weight!!property">font-weight</dfn>
889 <tr>
890 <td>Value:
892 <td><a href="#font-weight-normal-value"
893 title="normal!!font-weight">normal</a> | <a href="#bold">bold</a> | <a
894 href="#bolder">bolder</a> | <a href="#lighter">lighter</a> | <a
895 href="#font-weight-numeric-values" title="100...900 weight
896 values">100</a> | <a href="#font-weight-numeric-values"
897 title="100...900 weight values">200</a> | <a
898 href="#font-weight-numeric-values" title="100...900 weight
899 values">300</a> | <a href="#font-weight-numeric-values"
900 title="100...900 weight values">400</a> | <a
901 href="#font-weight-numeric-values" title="100...900 weight
902 values">500</a> | <a href="#font-weight-numeric-values"
903 title="100...900 weight values">600</a> | <a
904 href="#font-weight-numeric-values" title="100...900 weight
905 values">700</a> | <a href="#font-weight-numeric-values"
906 title="100...900 weight values">800</a> | <a
907 href="#font-weight-numeric-values" title="100...900 weight
908 values">900</a>
910 <tr>
911 <td>Initial:
913 <td>normal
915 <tr>
916 <td>Applies to:
918 <td>all elements
920 <tr>
921 <td>Inherited:
923 <td>yes
925 <tr>
926 <td>Percentages:
928 <td>N/A
930 <tr>
931 <td>Media:
933 <td>visual
935 <tr>
936 <td>Computed value:
938 <td>numeric weight value (see description)
940 <tr>
941 <td>Animatable:
943 <td>as <a
944 href="http://dev.w3.org/csswg/css3-transitions/#animtype-font-weight">font
945 weight</a>
946 </table>
948 <p>The <a href="#propdef-font-weight"
949 title="font-weight!!property">‘<code
950 class=property>font-weight</code>’</a> property specifies the weight of
951 glyphs in the font, their degree of blackness or stroke thickness.
953 <p>Values have the following meanings:
955 <dl>
956 <dt><dfn id=font-weight-numeric-values title="100...900 weight values">100
957 to 900</dfn>
959 <dd>These values form an ordered sequence, where each number indicates a
960 weight that is at least as dark as its predecessor. These roughly
961 correspond to the commonly used weight names below:
962 </dl>
964 <ul>
965 <li>100 - Thin
967 <li>200 - Extra Light (Ultra Light)
969 <li>300 - Light
971 <li>400 - Normal
973 <li>500 - Medium
975 <li>600 - Semi Bold (Demi Bold)
977 <li>700 - Bold
979 <li>800 - Extra Bold (Ultra Bold)
981 <li>900 - Black (Heavy)
982 </ul>
984 <dl>
985 <dt><dfn id=font-weight-normal-value
986 title="normal!!font-weight">normal</dfn>
988 <dd>Same as ‘<code class=css>400</code>’.
990 <dt><dfn id=bold>bold</dfn>
992 <dd>Same as ‘<code class=css>700</code>’.
994 <dt><dfn id=bolder>bolder</dfn>
996 <dd>Specifies a bolder weight than the inherited value.
998 <dt><dfn id=lighter>lighter</dfn>
1000 <dd>Specifies a lighter weight than the inherited value.
1001 </dl>
1003 <p>Font formats that use a scale other than a nine-step scale should map
1004 their scale onto the CSS scale so that 400 roughly corresponds with a face
1005 that would be labeled as Regular, Book, Roman and 700 roughly matches a
1006 face that would be labeled as Bold. Or weights may be inferred from the
1007 style names, ones that correspond roughly with the scale above. The scale
1008 is relative, so a face with a larger weight value must never appear
1009 lighter. If style names are used to infer weights, care should be taken to
1010 handle variations in style names across locales.
1012 <p>Quite often there are only a few weights available for a particular font
1013 family. When a weight is specified for which no face exists, a face with a
1014 nearby weight is used. In general, bold weights map to faces with heavier
1015 weights and light weights map to faces with lighter weights (see the <a
1016 href="#font-matching-algorithm">font matching section below</a> for a
1017 precise definition). The examples here illustrate which face is used for
1018 different weights, grey indicates a face for that weight does not exist so
1019 a face with a nearby weight is used:
1021 <div class=figure><img alt="weight mappings for a family with 400, 700 and
1022 900 weights" src=optimaweights.png>
1023 <p class=caption>Weight mappings for a font family with 400, 700 and 900
1024 weight faces
1025 </div>
1027 <div class=figure><img alt="weight mappings for a family with 300, 600
1028 weights" src=hiraginoweights.png>
1029 <p class=caption>Weight mappings for a font family with 300 and 600 weight
1030 faces
1031 </div>
1033 <p>Although the practice is not well-loved by typographers, bold faces are
1034 often synthesized by user agents for faces that lack actual bold faces.
1035 For the purposes of style matching, these faces must be treated as if they
1036 exist within the family. Authors can explicitly avoid this behavior by
1037 using the ‘<a href="#propdef-font-synthesis"><code
1038 class=property>font-synthesis</code></a>’ property.
1040 <p>Specified values of ‘<a href="#bolder"><code
1041 class=property>bolder</code></a>’ and ‘<a href="#lighter"><code
1042 class=property>lighter</code></a>’ indicate weights relative to the
1043 weight of the parent element. The computed weight is calculated based on
1044 the inherited <a href="#propdef-font-weight"
1045 title="font-weight!!property">‘<code
1046 class=property>font-weight</code>’</a> value using the chart below.
1048 <table class=data id=bolderlighter summary="Bolder/lighter mappings">
1049 <thead>
1050 <tr>
1051 <th>Inherited value
1053 <th>bolder
1055 <th>lighter
1057 <tbody>
1058 <tr>
1059 <th>100
1061 <td>400
1063 <td>100
1065 <tr>
1066 <th>200
1068 <td>400
1070 <td>100
1072 <tr>
1073 <th>300
1075 <td>400
1077 <td>100
1079 <tr>
1080 <th>400
1082 <td>700
1084 <td>100
1086 <tr>
1087 <th>500
1089 <td>700
1091 <td>100
1093 <tr>
1094 <th>600
1096 <td>900
1098 <td>400
1100 <tr>
1101 <th>700
1103 <td>900
1105 <td>400
1107 <tr>
1108 <th>800
1110 <td>900
1112 <td>700
1114 <tr>
1115 <th>900
1117 <td>900
1119 <td>700
1120 </table>
1122 <p>The table above is equivalent to selecting the next relative bolder or
1123 lighter face, given a font family containing normal and bold faces along
1124 with a thin and a heavy face. Authors who desire finer control over the
1125 exact weight values used for a given element may use numerical values
1126 instead of relative weights.</p>
1127 <!-- prop: font-stretch -->
1129 <h3 id=font-stretch-prop><span class=secno>3.3 </span>Font width: the <a
1130 href="#propdef-font-stretch">font-stretch</a> property</h3>
1132 <table class=propdef id=namefont-stretchvalue-normal-ultra-conde>
1133 <tbody>
1134 <tr>
1135 <td>Name:
1137 <td><dfn id=propdef-font-stretch
1138 title="font-stretch!!property">font-stretch</dfn>
1140 <tr>
1141 <td>Value:
1143 <td> <a href="#font-stretch-normal-value"
1144 title="normal!!font-stretch">normal</a> | <a
1145 href="#ultra-condensed">ultra-condensed</a> | <a
1146 href="#extra-condensed">extra-condensed</a> | <a
1147 href="#condensed">condensed</a> | <a
1148 href="#semi-condensed-">semi-condensed</a> | <a
1149 href="#semi-expanded">semi-expanded</a> | <a
1150 href="#expanded">expanded</a> | <a
1151 href="#extra-expanded">extra-expanded</a> | <a
1152 href="#ultra-expanded">ultra-expanded</a>
1154 <tr>
1155 <td>Initial:
1157 <td>normal
1159 <tr>
1160 <td>Applies to:
1162 <td>all elements
1164 <tr>
1165 <td>Inherited:
1167 <td>yes
1169 <tr>
1170 <td>Percentages:
1172 <td>N/A
1174 <tr>
1175 <td>Media:
1177 <td>visual
1179 <tr>
1180 <td>Computed value:
1182 <td>as specified
1184 <tr>
1185 <td>Animatable:
1187 <td>as <a href="#font-stretch-animation">font stretch</a>
1188 </table>
1190 <p>The <a href="#propdef-font-stretch"
1191 title="font-stretch!!property">‘<code
1192 class=property>font-stretch</code>’</a> property selects a normal,
1193 condensed, or expanded face from a font family. Absolute keyword values
1194 have the following ordering, from narrowest to widest:
1196 <ul>
1197 <li><dfn id=ultra-condensed>ultra-condensed</dfn>
1199 <li><dfn id=extra-condensed>extra-condensed</dfn>
1201 <li><dfn id=condensed>condensed</dfn>
1203 <li><dfn id=semi-condensed->semi-condensed </dfn>
1205 <li><dfn id=font-stretch-normal-value
1206 title="normal!!font-stretch">normal</dfn>
1208 <li><dfn id=semi-expanded>semi-expanded</dfn>
1210 <li><dfn id=expanded>expanded</dfn>
1212 <li><dfn id=extra-expanded>extra-expanded</dfn>
1214 <li><dfn id=ultra-expanded>ultra-expanded</dfn>
1215 </ul>
1217 <p>When a face does not exist for a given width, normal or condensed values
1218 map to a narrower face, otherwise a wider face. Conversely, expanded
1219 values map to a wider face, otherwise a narrower face. The figure below
1220 shows how the nine font-stretch property settings affect font selection
1221 for font family containing a variety of widths, grey indicates a width for
1222 which no face exists and a different width is substituted:
1224 <div class=figure><img alt="width mappings for a family with condensed,
1225 normal and expanded faces" src=universwidths.png>
1226 <p class=caption>Width mappings for a font family with condensed, normal
1227 and expanded width faces
1228 </div>
1230 <p id=font-stretch-animation>Animation of font stretch: Font stretch is
1231 interpolated in discrete steps. The interpolation happens as though the
1232 ordered values are equally spaced real numbers. The interpolation result
1233 is rounded to the nearest value, with values exactly halfway between two
1234 values rounded towards the later value in the list above.</p>
1235 <!-- prop: font-style -->
1237 <h3 id=font-style-prop><span class=secno>3.4 </span>Font style: the <a
1238 href="#propdef-font-style">font-style</a> property</h3>
1240 <table class=propdef id=namefont-stylevaluenormal-italic-oblique>
1241 <tbody>
1242 <tr>
1243 <td>Name:
1245 <td><dfn id=propdef-font-style
1246 title="font-style!!property">font-style</dfn>
1248 <tr>
1249 <td>Value:
1251 <td><a href="#font-style-normal-value"
1252 title="normal!!font-style">normal</a> | <a href="#italic">italic</a> |
1253 <a href="#oblique">oblique</a>
1255 <tr>
1256 <td>Initial:
1258 <td>normal
1260 <tr>
1261 <td>Applies to:
1263 <td>all elements
1265 <tr>
1266 <td>Inherited:
1268 <td>yes
1270 <tr>
1271 <td>Percentages:
1273 <td>N/A
1275 <tr>
1276 <td>Media:
1278 <td>visual
1280 <tr>
1281 <td>Computed value:
1283 <td>as specified
1285 <tr>
1286 <td>Animatable:
1288 <td>no
1289 </table>
1291 <p>The <a href="#propdef-font-style" title="font-style!!property">‘<code
1292 class=property>font-style</code>’</a> property allows italic or oblique
1293 faces to be selected. Italic forms are generally cursive in nature while
1294 oblique faces are typically sloped versions of the regular face. Oblique
1295 faces can be simulated by artificially sloping the glyphs of the regular
1296 face. Compare the artificially sloped renderings of Palatino ‘<code
1297 class=property>a</code>’ and Baskerville ‘<code
1298 class=property>N</code>’ in grey with the actual italic versions:
1300 <div class=figure><img alt="artificial sloping vs. real italics"
1301 src=realvsfakeitalics.png>
1302 <p class=caption>Artificial sloping versus real italics
1303 </div>
1305 <p>Values have the following meanings:
1307 <dl>
1308 <dt><dfn id=font-style-normal-value
1309 title="normal!!font-style">normal</dfn>
1311 <dd>selects a face that is classified as a normal face, one that is
1312 neither italic or obliqued
1314 <dt><dfn id=italic>italic</dfn>
1316 <dd>selects a font that is labeled as an italic face, or an oblique face
1317 if one is not
1319 <dt><dfn id=oblique>oblique</dfn>
1321 <dd>selects a font that is labeled as an oblique face, or an italic face
1322 if one is not
1323 </dl>
1325 <p>If no italic or oblique face is available, oblique faces can be
1326 synthesized by rendering non-obliqued faces with a right sloping
1327 transformation applied. When synthesizing these faces, the transformation
1328 should apply to all glyphs in the same way and not vary based on codepoint
1329 or due to horizontal or vertical line orientation.
1331 <p class=issue>It has been <a
1332 href="http://lists.w3.org/Archives/Public/www-style/2013May/0272.html">proposed</a>
1333 that for vertical text runs, synthetic italics should not mimic normal
1334 italic glyphs but instead mimic the customs of Japanese obliquing
1335 (斜体、shatai), where the obliquing is applied across the text run
1336 regardless of glyph orientation.
1338 <p>Many scripts lack the tradition of mixing a cursive form within text
1339 rendered with a normal face. Chinese, Japanese and Korean fonts almost
1340 always lack italic or oblique faces. Fonts that support a mixture of
1341 scripts will sometimes omit specific scripts such as Arabic from the set
1342 of glyphs supported in the italic face. User agents should be careful
1343 about making <a href="#character-map"><em>character map</em></a>
1344 assumptions across faces.</p>
1345 <!-- prop: font-size -->
1347 <h3 id=font-size-prop><span class=secno>3.5 </span>Font size: the <a
1348 href="#propdef-font-size">font-size</a> property</h3>
1350 <table class=propdef id=namefont-sizevalueltabsolute-sizegt-ltre>
1351 <tbody>
1352 <tr>
1353 <td>Name:
1355 <td><dfn id=propdef-font-size>font-size</dfn>
1357 <tr>
1358 <td>Value:
1360 <td><a href="#absolute-size-value"><var><absolute-size></var></a>
1361 | <a href="#relative-size-value"><var><relative-size></var></a> |
1362 <a href="#length-size-value"><var><length></var></a> | <a
1363 href="#percentage-size-value"><var><percentage></var></a>
1365 <tr>
1366 <td>Initial:
1368 <td>medium
1370 <tr>
1371 <td>Applies to:
1373 <td>all elements
1375 <tr>
1376 <td>Inherited:
1378 <td>yes
1380 <tr>
1381 <td>Percentages:
1383 <td>refer to parent element's font size
1385 <tr>
1386 <td>Media:
1388 <td>visual
1390 <tr>
1391 <td>Computed value:
1393 <td>absolute length
1395 <tr>
1396 <td>Animatable:
1398 <td>as <a
1399 href="http://dev.w3.org/csswg/css3-transitions/#animtype-length">length</a>
1400 </table>
1402 <p>This property indicates the desired height of glyphs from the font. For
1403 scalable fonts, the font-size is a scale factor applied to the EM unit of
1404 the font. (Note that certain glyphs may bleed outside their EM box.) For
1405 non-scalable fonts, the font-size is converted into absolute units and
1406 matched against the declared font-size of the font, using the same
1407 absolute coordinate space for both of the matched values. Values have the
1408 following meanings:
1410 <dl>
1411 <dt><dfn id=absolute-size-value><var><absolute-size></var></dfn>
1413 <dd> An <a
1414 href="#absolute-size-value"><var><absolute-size></var></a> keyword
1415 refers to an entry in a table of font sizes computed and kept by the user
1416 agent. Possible values are:
1417 <p> [ xx-small | x-small | small | medium | large | x-large | xx-large ]</p>
1419 <dt><dfn id=relative-size-value><var><relative-size></var></dfn>
1421 <dd> A <a href="#relative-size-value"><var><relative-size></var></a>
1422 keyword is interpreted relative to the table of font sizes and the
1423 computed ‘<a href="#propdef-font-size"><code
1424 class=property>font-size</code></a>’ of the parent element. Possible
1425 values are:
1426 <p> [ larger | smaller ]
1428 <p> For example, if the parent element has a font size of ‘<code
1429 class=property>medium</code>’, a value of ‘<code
1430 class=property>larger</code>’ will make the font size of the current
1431 element be ‘<code class=property>large</code>’. If the parent
1432 element's size is not close to a table entry, the user agent is free to
1433 interpolate between table entries or round off to the closest one. The
1434 user agent may have to extrapolate table values if the numerical value
1435 goes beyond the keywords.
1437 <dt><dfn id=length-size-value><var><length></var></dfn>
1439 <dd>A length value specifies an absolute font size (independent of the
1440 user agent's font table). Negative lengths are illegal.
1442 <dt><dfn id=percentage-size-value><var><percentage></var></dfn>
1444 <dd>A percentage value specifies an absolute font size relative to the
1445 parent element's font size. Use of percentage values, or values in
1446 ‘<code class=property>em</code>’s, leads to more robust and
1447 cascadable style sheets.
1448 </dl>
1450 <p>The following table provides user agent guidelines for the absolute-size
1451 scaling factor and their mapping to HTML heading and absolute font-sizes.
1452 The ‘<code class=property>medium</code>’ value is used as the
1453 reference middle value. The user agent may fine-tune these values for
1454 different fonts or different types of display devices.
1456 <table class=data>
1457 <thead>
1458 <tr>
1459 <th>CSS absolute-size values
1461 <th>xx-small
1463 <th>x-small
1465 <th>small
1467 <th>medium
1469 <th>large
1471 <th>x-large
1473 <th>xx-large
1475 <th>
1477 <tbody>
1478 <tr>
1479 <th>scaling factor
1481 <td>3/5
1483 <td>3/4
1485 <td>8/9
1487 <td>1
1489 <td>6/5
1491 <td>3/2
1493 <td>2/1
1495 <td>3/1
1497 <tr>
1498 <th>HTML headings
1500 <td>h6
1502 <td>
1504 <td>h5
1506 <td>h4
1508 <td>h3
1510 <td>h2
1512 <td>h1
1514 <td>
1516 <tr>
1517 <th>HTML font sizes
1519 <td>1
1521 <td>
1523 <td>2
1525 <td>3
1527 <td>4
1529 <td>5
1531 <td>6
1533 <td>7
1534 </table>
1536 <p class=note><em><strong>Note 1.</strong> To preserve readability, an UA
1537 applying these guidelines should nevertheless avoid creating font-size
1538 resulting in less than 9 device pixels per EM unit on a computer
1539 display.</em>
1541 <p class=note><em><strong>Note 2.</strong> In CSS1, the suggested scaling
1542 factor between adjacent indexes was 1.5 which user experience proved to be
1543 too large. In CSS2, the suggested scaling factor for computer screen
1544 between adjacent indexes was 1.2 which still created issues for the small
1545 sizes. The new scaling factor varies between each index to provide a
1546 better readability.</em>
1548 <p>The actual value of this property may differ from the computed value due
1549 a numerical value on ‘<a href="#propdef-font-size-adjust"><code
1550 class=property>font-size-adjust</code></a>’ and the unavailability of
1551 certain font sizes.
1553 <p>Child elements inherit the computed <a class=noxref
1554 href="#font-size-prop"> <span class=property>‘<code
1555 class=property>font-size</code>’</span></a> value (otherwise, the effect
1556 of <a class=noxref href="#font-size-adjust-prop"><span
1557 class=property>‘<code
1558 class=property>font-size-adjust</code>’</span></a> would compound).
1560 <div class=example>
1561 <p style="display:none">Example(s):
1563 <p>
1565 <pre>p { font-size: 12pt; }
1566 blockquote { font-size: larger }
1567 em { font-size: 150% }
1568 em { font-size: 1.5em }
1569 </pre>
1570 </div>
1571 <!-- prop: font-size-adjust -->
1573 <h3 id=font-size-adjust-prop><span class=secno>3.6 </span>Relative sizing:
1574 the <a href="#propdef-font-size-adjust">font-size-adjust</a> property</h3>
1576 <table class=propdef id=namefont-size-adjustvaluenone-auto-ltnum>
1577 <tbody>
1578 <tr>
1579 <td>Name:
1581 <td><dfn id=propdef-font-size-adjust>font-size-adjust</dfn>
1583 <tr>
1584 <td>Value:
1586 <td><a href="#font-size-adjust-none-value"
1587 title="none!!font-size-adjust">none</a> | <a
1588 href="#font-size-adjust-auto-value"
1589 title="auto!!font-size-adjust">auto</a> | <a
1590 href="#aspect-ratio-value"><var><number></var></a>
1592 <tr>
1593 <td>Initial:
1595 <td>none
1597 <tr>
1598 <td>Applies to:
1600 <td>all elements
1602 <tr>
1603 <td>Inherited:
1605 <td>yes
1607 <tr>
1608 <td>Percentages:
1610 <td>N/A
1612 <tr>
1613 <td>Media:
1615 <td>visual
1617 <tr>
1618 <td>Computed value:
1620 <td>as specified
1622 <tr>
1623 <td>Animatable:
1625 <td>as <a
1626 href="http://dev.w3.org/csswg/css3-transitions/#animtype-number">number</a>
1627 </table>
1629 <p>For any given font size, the apparent size and legibility of text varies
1630 across fonts. For scripts such as Latin or Cyrillic that distinguish
1631 between upper and lowercase letters, the relative height of lowercase
1632 letters compared to their uppercase counterparts is a determining factor
1633 of legibility. This is commonly referred to as the <a class=index-def
1634 href="#aspect-value" id=aspect-value0 title="aspect value"><dfn
1635 id=aspect-value>aspect value</dfn></a>. Precisely defined, it is equal to
1636 the x-height of a font divided by the font size.
1638 <p>In situations where font fallback occurs, fallback fonts may not share
1639 the same aspect ratio as the desired font family and will thus appear less
1640 readable. The font-size-adjust property is a way to preserve the
1641 readability of text when font fallback occurs. It does this by adjusting
1642 the font-size so that the x-height is the same regardless of the font
1643 used.
1645 <div class=example>
1646 <p>The style defined below defines Verdana as the desired font family, but
1647 if Verdana is not available Futura or Times will be used.</p>
1649 <pre>p {
1650 font-family: Verdana, Futura, Times;
1651 }
1653 <p>Lorem ipsum dolor sit amet, ...</p>
1654 </pre>
1656 <p>Verdana has a relatively high aspect ratio, lowercase letters are
1657 relatively tall compared to uppercase letters, so at small sizes text
1658 appears legible. Times has a lower aspect ratio and so if fallback
1659 occurs, the text will be less legible at small sizes than Verdana.</p>
1660 </div>
1662 <p>How text rendered in each of these fonts compares is shown below, the
1663 columns show text rendered in Verdana, Futura and Times. The same
1664 font-size value is used across cells within each row and red lines are
1665 included to show the differences in x-height. In the upper half each row
1666 is rendered in the same font-size value. The same is true for the lower
1667 half but in this half the font-size-adjust property is also set so that
1668 the actual font size is adjusted to preserve the x-height across each row.
1669 Note how small text remains relatively legible across each row in the
1670 lower half.
1672 <div class=figure><img alt="text with and without font-size-adjust"
1673 src=fontsizeadjust.png>
1674 <p class=caption>Text with and without the use of font-size-adjust
1675 </div>
1677 <p>This property allows authors to specify an aspect value for an element
1678 that will effectively preserve the x-height of the first choice font,
1679 whether it is substituted or not. Values have the following meanings:
1681 <dl>
1682 <dt><dfn id=font-size-adjust-none-value
1683 title="none!!font-size-adjust">none</dfn>
1685 <dd>Do not preserve the font's x-height.
1687 <dt><dfn id=font-size-adjust-auto-value
1688 title="auto!!font-size-adjust">auto</dfn>
1690 <dd>Behaves just like <number>, except the number used is the aspect
1691 value calculated by user agents for the first font in the list of fonts
1692 defined for the initial value of the <a href="#propdef-font-family"
1693 title="font-family!!property">‘<code
1694 class=property>font-family</code>’</a> property. Effectively this is
1695 the default font used when <a href="#propdef-font-family"
1696 title="font-family!!property">‘<code
1697 class=property>font-family</code>’</a> is not otherwise specified.
1698 <p>Authors can use this value to specify that font size should be
1699 normalized across fonts based on the x-height without the need to
1700 specify the aspect ratio explicitly.</p>
1702 <dt><dfn id=aspect-ratio-value><var><number></var></dfn>
1704 <dd>Specifies the aspect value used in the calculation below to calculate
1705 the adjusted font size:
1706 <pre>c = ( a / a' ) s
1707 </pre>
1709 <p>where:</p>
1711 <pre>s = font-size value
1712 a = aspect value as specified by the font-size-adjust property
1713 a' = aspect value of actual font
1714 c = adjusted font-size to use
1715 </pre>
1717 <p>This value applies to any font that is selected but in typical usage
1718 it should be based on the aspect value of the first font in the
1719 font-family list. If this is specified accurately, the <tt>(a/a')</tt>
1720 term in the formula above is effectively 1 for the first font and no
1721 adjustment occurs. If the value is specified inaccurately, text rendered
1722 using the first font in the family list will display differently in
1723 older user agents that don't support font-size-adjust.</p>
1724 </dl>
1726 <p>Authors can calculate the aspect value for a given font by comparing
1727 spans with the same content but different font-size-adjust properties. If
1728 the same font-size is used, the spans will match when the font-size-adjust
1729 value is accurate for the given font.
1731 <div class=example>
1732 <p>Two spans with borders are used to determine the aspect value of a
1733 font. The font-size is the same for both spans but the font-size-adjust
1734 property is specified only for the right span. Starting with a value of
1735 0.5, the aspect value can be adjusted until the borders around the two
1736 letters line up.</p>
1738 <pre>p {
1739 font-family: Futura;
1740 font-size: 500px;
1741 }
1743 span {
1744 border: solid 1px red;
1745 }
1747 .adjust {
1748 font-size-adjust: 0.5;
1749 }
1751 <p><span>b</span><span class="adjust">b</span></p>
1752 </pre>
1754 <div class=figure><img alt="Futura with an aspect value of 0.5"
1755 src=beforefontsizeadjust.png>
1756 <p class=caption>Futura with an aspect value of 0.5
1757 </div>
1759 <p>The box on the right is a bit bigger than the one on the left, so the
1760 aspect value of this font is something less than 0.5. Adjust the value
1761 until the boxes align.</p>
1762 </div>
1763 <!-- prop: font -->
1765 <h3 id=font-prop><span class=secno>3.7 </span>Shorthand font property: the
1766 <a href="#propdef-font">font</a> property</h3>
1768 <table class=propdef id=namefontvalue-ltlsquofont-stylersquogt-l>
1769 <tbody>
1770 <tr>
1771 <td>Name:
1773 <td><dfn id=propdef-font>font</dfn>
1775 <tr>
1776 <td>Value:
1778 <td>[ [ <var><<a href="#propdef-font-style"
1779 title="font-style!!property">‘<code
1780 class=property>font-style</code>’</a>></var> || <a
1781 href="#font-variant-css21-values"><var><font-variant-css21></var></a>
1782 || <var><<a href="#propdef-font-weight"
1783 title="font-weight!!property">‘<code
1784 class=property>font-weight</code>’</a>></var> || <var><<a
1785 href="#propdef-font-stretch" title="font-stretch!!property">‘<code
1786 class=property>font-stretch</code>’</a></var> ]? <var><‘<a
1787 href="#propdef-font-size"><code
1788 class=property>font-size</code></a>’></var> [ / <var><‘<code
1789 class=property>line-height</code>’></var> ]? <var><<a
1790 href="#propdef-font-family" title="font-family!!property">‘<code
1791 class=property>font-family</code>’</a>></var> ] | caption | icon |
1792 menu | message-box | small-caption | status-bar
1794 <tr>
1795 <td>Initial:
1797 <td>see individual properties
1799 <tr>
1800 <td>Applies to:
1802 <td>all elements
1804 <tr>
1805 <td>Inherited:
1807 <td>yes
1809 <tr>
1810 <td>Percentages:
1812 <td>see individual properties
1814 <tr>
1815 <td>Media:
1817 <td>visual
1819 <tr>
1820 <td>Computed value:
1822 <td>see individual properties
1824 <tr>
1825 <td>Animatable:
1827 <td>see individual properties
1828 </table>
1830 <p>The <span class=property>‘<a href="#propdef-font"><code
1831 class=property>font</code></a>’</span> property is, except as described
1832 below, a shorthand property for setting <a href="#propdef-font-style"
1833 title="font-style!!property">‘<code
1834 class=property>font-style</code>’</a>, <a href="#propdef-font-variant"
1835 title="font-variant!!property">‘<code
1836 class=property>font-variant</code>’</a>, <a href="#propdef-font-weight"
1837 title="font-weight!!property">‘<code
1838 class=property>font-weight</code>’</a>, <a href="#propdef-font-stretch"
1839 title="font-stretch!!property">‘<code
1840 class=property>font-stretch</code>’</a>, <span class=property>‘<a
1841 href="#propdef-font-size"><code
1842 class=property>font-size</code></a>’</span>, <a class=property
1843 href="http://www.w3.org/TR/CSS2/visudet.html#propdef-line-height">‘<code
1844 class=property>line-height</code>’</a>, <a href="#propdef-font-family"
1845 title="font-family!!property">‘<code
1846 class=property>font-family</code>’</a> at the same place in the
1847 stylesheet. Values for the <a href="#propdef-font-variant"
1848 title="font-variant!!property">‘<code
1849 class=property>font-variant</code>’</a> property may also be included
1850 but only those supported in CSS 2.1, none of the font-variant values added
1851 in this specification can be used in the <span class=property>‘<a
1852 href="#propdef-font"><code class=property>font</code></a>’</span>
1853 shorthand:
1855 <pre
1856 class=prod><dfn id=font-variant-css21-values><var><font-variant-css21></var></dfn> = [normal | small-caps]</pre>
1858 <p>The syntax of this property is based on a traditional typographical
1859 shorthand notation to set multiple properties related to fonts.
1861 <p>All subproperties of the ‘<a href="#propdef-font"><code
1862 class=property>font</code></a>’ property are first reset to their
1863 initial values, including those listed above plus <span
1864 class=property>‘<a href="#propdef-font-size-adjust"><code
1865 class=property>font-size-adjust</code></a>’</span>, <span
1866 class=property>‘<a href="#propdef-font-kerning"><code
1867 class=property>font-kerning</code></a>’</span>, subproperties of <a
1868 href="#propdef-font-variant" title="font-variant!!property">‘<code
1869 class=property>font-variant</code>’</a> and and <span>‘<a
1870 href="#propdef-font-language-override"><code
1871 class=property>font-language-override</code></a>’</span>. Then, those
1872 properties that are given explicit values in the <span
1873 class=property>‘<a href="#propdef-font"><code
1874 class=property>font</code></a>’</span> shorthand are set to those
1875 values. For a definition of allowed and initial values, see the previously
1876 defined properties. For reasons of backwards compatibility, it is not
1877 possible to set <span class=property>‘<a
1878 href="#propdef-font-size-adjust"><code
1879 class=property>font-size-adjust</code></a>’</span> to anything other
1880 than its initial value using the <span class=property>‘<a
1881 href="#propdef-font"><code class=property>font</code></a>’</span>
1882 shorthand property; instead, use the individual property.
1884 <div class=example>
1885 <p style="display:none">Example(s):
1887 <p>
1889 <pre>p { font: 12pt/14pt sans-serif }
1890 p { font: 80% sans-serif }
1891 p { font: x-large/110% "new century schoolbook", serif }
1892 p { font: bold italic large Palatino, serif }
1893 p { font: normal small-caps 120%/120% fantasy }
1894 p { font: condensed oblique 12pt "Helvetica Neue", serif; }
1895 </pre>
1897 <p> In the second rule, the font size percentage value (‘<code
1898 class=css>80%</code>’) refers to the computed ‘<a
1899 href="#propdef-font-size"><code class=property>font-size</code></a>’ of
1900 the parent element. In the third rule, the line height percentage
1901 (‘<code class=css>110%</code>’) refers to the font size of the
1902 element itself.
1904 <p>The first three rules do not specify the <a
1905 href="#propdef-font-variant" title="font-variant!!property">‘<code
1906 class=property>font-variant</code>’</a> and <a
1907 href="#propdef-font-weight" title="font-weight!!property">‘<code
1908 class=property>font-weight</code>’</a> explicitly, so these properties
1909 receive their initial values (‘<a href="#normal"><code
1910 class=property>normal</code></a>’). Notice that the font family name
1911 "new century schoolbook", which contains spaces, is enclosed in quotes.
1912 The fourth rule sets the <a href="#propdef-font-weight"
1913 title="font-weight!!property">‘<code
1914 class=property>font-weight</code>’</a> to ‘<a href="#bold"><code
1915 class=property>bold</code></a>’, the <a href="#propdef-font-style"
1916 title="font-style!!property">‘<code
1917 class=property>font-style</code>’</a> to ‘<a href="#italic"><code
1918 class=property>italic</code></a>’, and implicitly sets <a
1919 href="#propdef-font-variant" title="font-variant!!property">‘<code
1920 class=property>font-variant</code>’</a> to ‘<a href="#normal"><code
1921 class=property>normal</code></a>’.
1923 <p> The fifth rule sets the <a href="#propdef-font-variant"
1924 title="font-variant!!property">‘<code
1925 class=property>font-variant</code>’</a> (‘<a href="#small-caps"><code
1926 class=property>small-caps</code></a>’), the <span class=property>‘<a
1927 href="#propdef-font-size"><code
1928 class=property>font-size</code></a>’</span> (120% of the parent's font
1929 size), the <a class=property
1930 href="http://www.w3.org/TR/CSS2/visudet.html#propdef-line-height">‘<code
1931 class=property>line-height</code>’</a> (120% of the font size) and the
1932 <a href="#propdef-font-family" title="font-family!!property">‘<code
1933 class=property>font-family</code>’</a> (‘<a href="#fantasy"><code
1934 class=property>fantasy</code></a>’). It follows that the keyword ‘<a
1935 href="#normal"><code class=property>normal</code></a>’ applies to the
1936 two remaining properties: <a href="#propdef-font-style"
1937 title="font-style!!property">‘<code
1938 class=property>font-style</code>’</a> and <a
1939 href="#propdef-font-weight" title="font-weight!!property">‘<code
1940 class=property>font-weight</code>’</a>.
1942 <p>The sixth rule sets the <a href="#propdef-font-style"
1943 title="font-style!!property">‘<code
1944 class=property>font-style</code>’</a>, <a href="#propdef-font-stretch"
1945 title="font-stretch!!property">‘<code
1946 class=property>font-stretch</code>’</a>, <span class=property>‘<a
1947 href="#propdef-font-size"><code
1948 class=property>font-size</code></a>’</span>, and <a
1949 href="#propdef-font-family" title="font-family!!property">‘<code
1950 class=property>font-family</code>’</a>, the other font properties being
1951 set to their initial values.
1952 </div>
1954 <p>Since the <a href="#propdef-font-stretch"
1955 title="font-stretch!!property">‘<code
1956 class=property>font-stretch</code>’</a> property was not defined in CSS
1957 2.1, when using <a href="#propdef-font-stretch"
1958 title="font-stretch!!property">‘<code
1959 class=property>font-stretch</code>’</a> values within ‘<a
1960 href="#propdef-font"><code class=property>font</code></a>’ rules,
1961 authors should include a extra version compatible with older user agents:
1963 <pre>p {
1964 font: 80% sans-serif; /* for older user agents */
1965 font: condensed 80% sans-serif;
1966 }</pre>
1968 <p>The following values refer to system fonts:
1970 <dl>
1971 <dt><strong>caption</strong>
1973 <dd>The font used for captioned controls (e.g., buttons, drop-downs,
1974 etc.).
1976 <dt><strong>icon</strong>
1978 <dd>The font used to label icons.
1980 <dt><strong>menu</strong>
1982 <dd>The font used in menus (e.g., dropdown menus and menu lists).
1984 <dt><strong>message-box</strong>
1986 <dd>The font used in dialog boxes.
1988 <dt><strong>small-caption</strong>
1990 <dd>The font used for labeling small controls.
1992 <dt><strong>status-bar</strong>
1994 <dd>The font used in window status bars.
1995 </dl>
1997 <p>System fonts may only be set as a whole; that is, the font family, size,
1998 weight, style, etc. are all set at the same time. These values may then be
1999 altered individually if desired. If no font with the indicated
2000 characteristics exists on a given platform, the user agent should either
2001 intelligently substitute (e.g., a smaller version of the ‘<code
2002 class=property>caption</code>’ font might be used for the ‘<code
2003 class=property>small-caption</code>’ font), or substitute a user agent
2004 default font. As for regular fonts, if, for a system font, any of the
2005 individual properties are not part of the operating system's available
2006 user preferences, those properties should be set to their initial values.
2008 <p>That is why this property is "almost" a shorthand property: system fonts
2009 can only be specified with this property, not with <a
2010 href="#propdef-font-family" title="font-family!!property">‘<code
2011 class=property>font-family</code>’</a> itself, so <span
2012 class=property>‘<a href="#propdef-font"><code
2013 class=property>font</code></a>’</span> allows authors to do more than
2014 the sum of its subproperties. However, the individual properties such as
2015 <a href="#propdef-font-weight" title="font-weight!!property">‘<code
2016 class=property>font-weight</code>’</a> are still given values taken from
2017 the system font, which can be independently varied.
2019 <p>Note that the keywords used for the system fonts listed above are only
2020 treated as keywords when they occur in the initial position, in other
2021 positions the same string is treated as part of the font family name:
2023 <pre> font: menu; /* use the font settings for system menus */
2024 font: large menu; /* use a font family named "menu" */</pre>
2026 <div class=example>
2027 <p style="display:none">Example(s):
2029 <p>
2031 <pre>button { font: 300 italic 1.3em/1.7em "FB Armada", sans-serif }
2032 button p { font: menu }
2033 button p em { font-weight: bolder }
2034 </pre>
2036 <p>If the font used for dropdown menus on a particular system happened to
2037 be, for example, 9-point Charcoal, with a weight of 600, then P elements
2038 that were descendants of BUTTON would be displayed as if this rule were
2039 in effect:
2041 <pre>button p { font: 600 9pt Charcoal }
2042 </pre>
2044 <p>Because the <span class=property>‘<a href="#propdef-font"><code
2045 class=property>font</code></a>’</span> shorthand resets to its initial
2046 value any property not explicitly given a value, this has the same effect
2047 as this declaration:
2049 <pre>button p {
2050 font-style: normal;
2051 font-variant: normal;
2052 font-weight: 600;
2053 font-size: 9pt;
2054 line-height: normal;
2055 font-family: Charcoal
2056 }
2057 </pre>
2058 </div>
2059 <!-- prop: font-synthesis -->
2061 <h3 id=font-synthesis-prop><span class=secno>3.8 </span>Controlling
2062 synthetic faces: the <a href="#propdef-font-synthesis">font-synthesis</a>
2063 property</h3>
2065 <table class=propdef id=namefont-synthesisvaluenone-weight-style>
2066 <tbody>
2067 <tr>
2068 <td>Name:
2070 <td><dfn id=propdef-font-synthesis>font-synthesis</dfn>
2072 <tr>
2073 <td>Value:
2075 <td>none | [ weight || style ]
2077 <tr>
2078 <td>Initial:
2080 <td>weight style
2082 <tr>
2083 <td>Applies to:
2085 <td>all elements
2087 <tr>
2088 <td>Inherited:
2090 <td>yes
2092 <tr>
2093 <td>Percentages:
2095 <td>N/A
2097 <tr>
2098 <td>Media:
2100 <td>visual
2102 <tr>
2103 <td>Computed value:
2105 <td>as specified
2107 <tr>
2108 <td>Animatable:
2110 <td>no
2111 </table>
2113 <p>This property controls whether user agents are allowed to synthesize
2114 bold or oblique font faces when a font family lacks bold or italic faces.
2115 If ‘<a href="#weight"><code class=property>weight</code></a>’ is not
2116 specified, user agents must not synthesize bold faces and if ‘<code
2117 class=property>style</code>’ is not specified user agents must not
2118 synthesize italic faces. A value of ‘<code class=property>none</code>’
2119 disallows all synthetic faces.
2121 <div class=example>
2122 <p>The style rule below disables the use of synthetically obliqued Arabic:</p>
2124 <pre>*:lang(ar) { font-synthesis: none; }
2125 </pre>
2126 </div>
2128 <h2 id=font-resources><span class=secno>4 </span>Font Resources</h2>
2130 <h3 id=font-face-rule><span class=secno>4.1 </span>The <dfn
2131 id=at-font-face-rule style="font-weight: inherit; font-style:
2132 inherit"><code>@font-face</code></dfn> rule</h3>
2134 <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule allows
2135 for linking to fonts that are automatically fetched and activated when
2136 needed. This allows authors to select a font that closely matches the
2137 design goals for a given page rather than limiting the font choice to a
2138 set of fonts available on all platforms. A set of font descriptors define
2139 the location of a font resource, either locally or externally, along with
2140 the style characteristics of an individual face. Multiple <a
2141 href="#at-font-face-rule"><code>@font-face</code></a> rules can be used to
2142 construct font families with a variety of faces. Using CSS font matching
2143 rules, a user agent can selectively download only those faces that are
2144 needed for a given piece of text.
2146 <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule
2147 consists of the <a href="#at-font-face-rule"><code>@font-face</code></a>
2148 at-keyword followed by a block of descriptor declarations. In terms of the
2149 grammar, this specification defines the following productions:
2151 <pre><dfn id=fontfacerule>font_face_rule</dfn>
2152 : <a href="#fontfacesym"><i>FONT_FACE_SYM</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#descriptordeclaration"><i>descriptor_declaration</i></a>? [ ';' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#descriptordeclaration"><i>descriptor_declaration</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
2153 ;
2155 <dfn id=descriptordeclaration>descriptor_declaration</dfn>
2156 : <a href="http://www.w3.org/TR/CSS21/grammar.html#grammar"><i>property</i></a> ':' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/grammar.html#grammar"><i>expr</i></a>
2157 ;</pre>
2159 <p>The following new definitions are introduced:
2161 <pre>- -|\\0{0,4}2d(\r\n|[ \t\r\n\f])?
2162 F f|\\0{0,4}(46|66)(\r\n|[ \t\r\n\f])?</pre>
2164 <p>The following new token is introduced:
2166 <pre>@{F}{O}{N}{T}{-}{F}{A}{C}{E} {return <dfn id=fontfacesym>FONT_FACE_SYM</dfn>;}</pre>
2168 <p>Each <a href="#at-font-face-rule"><code>@font-face</code></a> rule
2169 specifies a value for every font descriptor, either implicitly or
2170 explicitly. Those not given explicit values in the rule take the initial
2171 value listed with each descriptor in this specification. These descriptors
2172 apply solely within the context of the <a
2173 href="#at-font-face-rule"><code>@font-face</code></a> rule in which they
2174 are defined, and do not apply to document language elements. There is no
2175 notion of which elements the descriptors apply to or whether the values
2176 are inherited by child elements. When a given descriptor occurs multiple
2177 times in a given <a href="#at-font-face-rule"><code>@font-face</code></a>
2178 rule, only the last descriptor declaration is used and all prior
2179 declarations for that descriptor are ignored.
2181 <div class=example>
2182 <p>To use a downloadable font called Gentium:</p>
2184 <pre>
2185 @font-face {
2186 font-family: Gentium;
2187 src: url(http://example.com/fonts/Gentium.ttf);
2188 }
2190 p { font-family: Gentium, serif; }
2191 </pre>
2193 <p>The user agent will download Gentium and use it when rendering text
2194 within paragraph elements. If for some reason the site serving the font
2195 is unavailable, the default serif font will be used.</p>
2196 </div>
2198 <p>A given set of <a href="#at-font-face-rule"><code>@font-face</code></a>
2199 rules define a set of fonts available for use within the documents that
2200 contain these rules. When font matching is done, fonts defined using these
2201 rules are considered before other available fonts on a system.
2203 <p>Downloaded fonts are only available to documents that reference them.
2204 The process of activating these fonts must not make them available to
2205 other applications or to documents that don't directly link to the same
2206 font. User agent implementers might consider it convenient to use
2207 downloaded fonts when rendering characters in other documents for which no
2208 other available font exists as part of the system font fallback procedure.
2209 However, this would cause a security leak since the contents of one page
2210 would be able to affect other pages, something an attacker could use as an
2211 attack vector. These restrictions do not affect caching behavior, fonts
2212 are cached the same way other web resources are cached.
2214 <p>This at-rule follows the forward-compatible parsing rules of CSS. Like
2215 properties in a declaration block, declarations of any descriptors that
2216 are not supported by the user agent must be ignored. <a
2217 href="#at-font-face-rule"><code>@font-face</code></a> rules require a
2218 font-family and src descriptor; if either of these are missing, the <a
2219 href="#at-font-face-rule"><code>@font-face</code></a> rule is invalid and
2220 must be ignored entirely.
2222 <p>In cases where user agents have limited platform resources or implement
2223 the ability to disable downloadable font resources, <a
2224 href="#at-font-face-rule"><code>@font-face</code></a> rules must simply be
2225 ignored; the behavior of individual descriptors as defined in this
2226 specification should not be altered.
2228 <h3 id=font-family-desc><span class=secno>4.2 </span>Font family: the <a
2229 href="#descdef-font-family">font-family</a> descriptor</h3>
2231 <table class=descdef>
2232 <tbody>
2233 <tr>
2234 <td>Name:
2236 <td><dfn id=descdef-font-family
2237 title="font-family!!descriptor">font-family</dfn>
2239 <tr>
2240 <td>Value:
2242 <td><a href="#family-name-value"><var><family-name></var></a>
2244 <tr>
2245 <td><em>Initial:</em>
2247 <td>N/A
2248 </table>
2250 <p>This descriptor defines the font family name that will be used in all
2251 CSS font family name matching. It is required for the <a
2252 href="#at-font-face-rule"><code>@font-face</code></a> rule to be valid. It
2253 overrides the font family names contained in the underlying font data. If
2254 the font family name is the same as a font family available in a given
2255 user's environment, it effectively hides the underlying font for documents
2256 that use the stylesheet. This permits a web author to freely choose
2257 font-family names without worrying about conflicts with font family names
2258 present in a given user's environment. Likewise, platform substitutions
2259 for a given font family name must not be used.
2261 <h3 id=src-desc><span class=secno>4.3 </span>Font reference: the <a
2262 href="#descdef-src">src</a> descriptor</h3>
2264 <table class=descdef>
2265 <tbody>
2266 <tr>
2267 <td>Name:
2269 <td><dfn id=descdef-src>src</dfn>
2271 <tr>
2272 <td>Value:
2274 <td>[ <url> [format(<string> #)]? | <a
2275 href="#font-face-name-value"><var><font-face-name></var></a> ] #
2277 <tr>
2278 <td><em>Initial:</em>
2280 <td>N/A
2281 </table>
2283 <p>This descriptor specifies the resource containing font data. It is
2284 required for the <a href="#at-font-face-rule"><code>@font-face</code></a>
2285 rule to be valid. Its value is a prioritized, comma-separated list of
2286 external references or locally-installed font face names. When a font is
2287 needed the user agent iterates over the set of references listed, using
2288 the first one it can successfully activate. Fonts containing invalid data
2289 or local font faces that are not found are ignored and the user agent
2290 loads the next font in the list.
2292 <p>As with other URLs in CSS, the URL may be relative, in which case it is
2293 resolved relative to the location of the style sheet containing the <a
2294 href="#at-font-face-rule"><code>@font-face</code></a> rule. In the case of
2295 SVG fonts, the URL points to an element within a document containing SVG
2296 font definitions. If the element reference is omitted, a reference to the
2297 first defined font is implied. Similarly, font container formats that can
2298 contain more than one font must load one and only one of the fonts for a
2299 given <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
2300 Fragment identifiers are used to indicate which font to load. If a
2301 container format lacks a defined fragment identifier scheme,
2302 implementations should use a simple 1-based indexing scheme (e.g.
2303 "font-collection#1" for the first font, "font-collection#2" for the second
2304 font).
2306 <pre>
2307 src: url(fonts/simple.ttf); /* load simple.ttf relative to stylesheet location */
2308 src: url(/fonts/simple.ttf); /* load simple.ttf from absolute location */
2309 src: url(fonts.svg#simple); /* load SVG font with id 'simple' */
2310 </pre>
2312 <p>External references consist of a URL, followed by an optional hint
2313 describing the format of the font resource referenced by that URL. The
2314 format hint contains a comma-separated list of format strings that denote
2315 well-known font formats. Conformant user agents must skip downloading a
2316 font resource if the format hints indicate only unsupported or unknown
2317 font formats. If no format hints are supplied, the user agent should
2318 download the font resource.
2320 <pre>
2321 /* load WOFF font if possible, otherwise use OpenType font */
2322 @font-face {
2323 font-family: bodytext;
2324 src: url(ideal-sans-serif.woff) format("woff"),
2325 url(basic-sans-serif.ttf) format("opentype");
2326 }
2327 </pre>
2329 <p>Format strings defined by this specification:
2331 <table class=data id=fontformats>
2332 <thead>
2333 <tr>
2334 <th>String
2336 <th>Font Format
2338 <th>Common extensions
2340 <tbody>
2341 <tr>
2342 <th>"woff"
2344 <td><a href="http://www.w3.org/TR/WOFF/">WOFF (Web Open Font Format)</a>
2346 <td>.woff
2348 <tr>
2349 <th>"truetype"
2351 <td><a
2352 href="http://www.microsoft.com/typography/otspec/default.htm">TrueType</a>
2354 <td>.ttf
2356 <tr>
2357 <th>"opentype"
2359 <td><a
2360 href="http://www.microsoft.com/typography/otspec/default.htm">OpenType</a>
2362 <td>.ttf, .otf
2364 <tr>
2365 <th>"embedded-opentype"
2367 <td><a
2368 href="http://www.w3.org/Submission/2008/SUBM-EOT-20080305/">Embedded
2369 OpenType</a>
2371 <td>.eot
2373 <tr>
2374 <th>"svg"
2376 <td><a href="http://www.w3.org/TR/SVG/fonts.html">SVG Font</a>
2378 <td>.svg, .svgz
2379 </table>
2381 <p>Given the overlap in common usage between TrueType and OpenType, the
2382 format hints "truetype" and "opentype" must be considered as synonymous; a
2383 format hint of "opentype" does not imply that the font contains Postscript
2384 CFF style glyph data or that it contains OpenType layout information (see
2385 <a href="#platform-props-to-css">Appendix A</a> for more background on
2386 this).
2388 <p>When authors would prefer to use a locally available copy of a given
2389 font and download it if it's not, <code>local()</code> can be used. The
2390 locally-installed <dfn
2391 id=font-face-name-value><var><font-face-name></var></dfn> argument
2392 to <code>local()</code> is a format-specific string that uniquely
2393 identifies a single font face within a larger family. The syntax for a <a
2394 href="#font-face-name-value"><var><font-face-name></var></a> is a
2395 unique font face name enclosed by "local(" and ")". The name can
2396 optionally be enclosed in quotes. If unquoted, the unquoted font family
2397 name processing conventions apply; the name must be a sequence of
2398 identifiers separated by whitespace which is converted to a string by
2399 joining the identifiers together separated by a single space.
2401 <pre>
2402 /* regular face of Gentium */
2403 @font-face {
2404 font-family: MyGentium;
2405 src: local(Gentium), /* use locally available Gentium */
2406 url(Gentium.ttf); /* otherwise, download it */
2407 }
2408 </pre>
2410 <p>For OpenType and TrueType fonts, this string is used to match only the
2411 Postscript name or the full font name in the name table of locally
2412 available fonts. Which type of name is used varies by platform and font,
2413 so authors should include both of these names to assure proper matching
2414 across platforms. Platform substitutions for a given font name must not be
2415 used.
2417 <pre>
2418 /* bold face of Gentium */
2419 @font-face {
2420 font-family: MyGentium;
2421 src: local(Gentium Bold), /* full font name */
2422 local(Gentium-Bold), /* Postscript name */
2423 url(GentiumBold.ttf); /* otherwise, download it */
2424 font-weight: bold;
2425 }
2426 </pre>
2428 <p>Just as a <a href="#at-font-face-rule"><code>@font-face</code></a> rule
2429 specifies the characteristics of a single font within a family, the unique
2430 name used with <code>local()</code> specifies a single font, not an entire
2431 font family. Defined in terms of OpenType font data, the Postscript name
2432 is found in the font's <a
2433 href="http://www.microsoft.com/typography/otspec/name.htm">name table</a>,
2434 in the name record with nameID = 6 (see <a href="#OPENTYPE"
2435 rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> for more details). The
2436 Postscript name is the commonly used key for all fonts on OSX and for
2437 Postscript CFF fonts under Windows. The full font name (nameID = 4) is
2438 used as a unique key for fonts with TrueType glyphs on Windows.
2440 <p>For OpenType fonts with multiple localizations of the full font name,
2441 the US English version is used (language ID = 0x409 for Windows and
2442 language ID = 0 for Macintosh) or the first localization when a US English
2443 full font name is not available (the OpenType specification recommends
2444 that <a href="http://www.microsoft.com/typography/otspec/recom.htm">all
2445 fonts minimally include US English names</a>). User agents that also match
2446 other full font names, e.g. matching the Dutch name when the current
2447 system locale is set to Dutch, are considered non-conformant. This is done
2448 not to prefer English but to avoid matching inconsistencies across font
2449 versions and OS localizations, since font style names (e.g. "Bold") are
2450 frequently localized into many languages and the set of localizations
2451 available varies widely across platform and font version. User agents that
2452 match a concatenation of family name (nameID = 1) with style name (nameID
2453 = 2) are considered non-conformant.
2455 <p>This also allows for referencing faces that belong to larger families
2456 that cannot otherwise be referenced.
2458 <div class=example>
2459 <p>Use a local font or reference an SVG font in another document:</p>
2461 <pre>
2462 @font-face {
2463 font-family: Headline;
2464 src: local(Futura-Medium),
2465 url(fonts.svg#MyGeometricModern) format("svg");
2466 }
2467 </pre>
2469 <p>Create an alias for local Japanese fonts on different platforms:</p>
2471 <pre>
2472 @font-face {
2473 font-family: jpgothic;
2474 src: local(HiraKakuPro-W3), local(Meiryo), local(IPAPGothic);
2475 }
2476 </pre>
2478 <p>Reference a font face that cannot be matched within a larger family:</p>
2480 <pre>
2481 @font-face {
2482 font-family: Hoefler Text Ornaments;
2483 /* has the same font properties as Hoefler Text Regular */
2484 src: local(HoeflerText-Ornaments);
2485 }
2486 </pre>
2488 <p>Since localized fullnames never match, a document with the header style
2489 rules below would always render using the default serif font, regardless
2490 whether a particular system locale parameter is set to Finnish or not:</p>
2492 <pre>
2493 @font-face {
2494 font-family: SectionHeader;
2495 src: local("Arial Lihavoitu"); /* Finnish fullname for Arial Bold, should fail */
2496 font-weight: bold;
2497 }
2499 h2 { font-family: SectionHeader, serif; }
2500 </pre>
2502 <p>A conformant user agent would never load the font ‘<code
2503 class=css>gentium.eot</code>’ in the example below, since it is
2504 included in the first definition of the ‘<a href="#descdef-src"><code
2505 class=property>src</code></a>’ descriptor which is overridden by the
2506 second definition in the same <a
2507 href="#at-font-face-rule"><code>@font-face</code></a> rule:</p>
2509 <pre>
2510 @font-face {
2511 font-family: MainText;
2512 src: url(gentium.eot); /* for use with older non-conformant user agents */
2513 src: local("Gentium"), url(gentium.ttf); /* Overrides src definition */
2514 }
2515 </pre>
2516 </div>
2518 <h3 id=font-prop-desc><span class=secno>4.4 </span>Font property
2519 descriptors: the <a href="#descdef-font-style">font-style</a>, <a
2520 href="#descdef-font-weight">font-weight</a>, <a
2521 href="#descdef-font-stretch">font-stretch</a> descriptors</h3>
2523 <table class=descdef>
2524 <tbody>
2525 <tr>
2526 <td>Name:
2528 <td><dfn id=descdef-font-style
2529 title="font-style!!descriptor">font-style</dfn>
2531 <tr>
2532 <td>Value:
2534 <td>normal | italic | oblique
2536 <tr>
2537 <td><em>Initial:</em>
2539 <td>normal
2540 </table>
2542 <table class=descdef>
2543 <tbody>
2544 <tr>
2545 <td>Name:
2547 <td><dfn id=descdef-font-weight
2548 title="font-weight!!descriptor">font-weight</dfn>
2550 <tr>
2551 <td>Value:
2553 <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
2555 <tr>
2556 <td><em>Initial:</em>
2558 <td>normal
2559 </table>
2561 <table class=descdef>
2562 <tbody>
2563 <tr>
2564 <td>Name:
2566 <td><dfn id=descdef-font-stretch
2567 title="font-stretch!!descriptor">font-stretch</dfn>
2569 <tr>
2570 <td>Value:
2572 <td>normal | ultra-condensed | extra-condensed | condensed |
2573 semi-condensed | semi-expanded | expanded | extra-expanded |
2574 ultra-expanded
2576 <tr>
2577 <td><em>Initial:</em>
2579 <td>normal
2580 </table>
2582 <p>These descriptors define the characteristics of a font face and are used
2583 in the process of matching styles to specific faces. For a font family
2584 defined with several <a
2585 href="#at-font-face-rule"><code>@font-face</code></a> rules, user agents
2586 can either download all faces in the family or use these descriptors to
2587 selectively download font faces that match actual styles used in document.
2588 The values for these descriptors are the same as those for the
2589 corresponding font properties except that relative keywords are not
2590 allowed, ‘<a href="#bolder"><code class=property>bolder</code></a>’
2591 and ‘<a href="#lighter"><code class=property>lighter</code></a>’. If
2592 these descriptors are omitted, initial values are assumed.
2594 <p>The value for these font face style attributes is used in place of the
2595 style implied by the underlying font data. This allows authors to combine
2596 faces in flexible combinations, even in situations where the original font
2597 data was arranged differently. User agents that implement synthetic
2598 bolding and obliquing must only apply synthetic styling in cases where the
2599 font descriptors imply this is needed, rather than based on the style
2600 attributes implied by the font data.
2602 <h3 id=unicode-range-desc><span class=secno>4.5 </span>Character range: the
2603 <a href="#descdef-unicode-range">unicode-range</a> descriptor</h3>
2605 <table class=descdef>
2606 <tbody>
2607 <tr>
2608 <td>Name:
2610 <td><dfn id=descdef-unicode-range>unicode-range</dfn>
2612 <tr>
2613 <td>Value:
2615 <td><a href="#urange-value"><var><urange></var></a> #
2617 <tr>
2618 <td><em>Initial:</em>
2620 <td>U+0-10FFFF
2621 </table>
2623 <p>This descriptor defines the set of Unicode codepoints that may be
2624 supported by the font face for which it is declared. The descriptor value
2625 is a comma-delimited list of Unicode range (<a
2626 href="#urange-value"><var><urange></var></a>) values. The union of
2627 these ranges defines the set of codepoints that serves as a hint for user
2628 agents when deciding whether or not to download a font resource for a
2629 given text run.
2631 <p>Each <dfn id=urange-value><var><urange></var></dfn> value is a <a
2632 href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
2633 title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token made up of a
2634 "U+" or "u+" prefix followed by a codepoint range in one of the three
2635 forms listed below. Ranges that do not fit one of the these forms are
2636 invalid and cause the declaration to be ignored.
2638 <dl>
2639 <dt>single codepoint (e.g. U+416)
2641 <dd>a valid Unicode codepoint, represented as one to six hexadecimal
2642 digits
2644 <dt>interval range (e.g. U+400-4ff)
2646 <dd>represented as two hyphen-separated valid Unicode codepoints
2647 indicating the inclusive start and end codepoints of a range
2649 <dt>wildcard range (e.g. U+4??)
2651 <dd>defined by the set of codepoints implied when trailing ‘<code
2652 class=css>?</code>’ characters signify any hexadeximal digit
2653 </dl>
2655 <p>Individual codepoints are written using hexadecimal values that
2656 correspond to <a href="http://www.unicode.org/charts/">Unicode character
2657 codepoints</a>. Valid Unicode codepoint values vary between 0 and 10FFFF
2658 inclusive. Digit values of codepoints are ASCII case-insensitive. For
2659 interval ranges, the start and end codepoints must be valid Unicode values
2660 and the end codepoint must be greater than or equal to the start
2661 codepoint.
2663 <p>Wildcard ranges specified with ‘?’ that lack an initial digit (e.g.
2664 "U+???") are valid and equivalent to a wildcard range with an initial zero
2665 digit (e.g. "U+0???" = "U+0000-0FFF"). Wildcard ranges that extend beyond
2666 the range of valid Unicode codepoints are invalid. Because of this, the
2667 maximum number of trailing ‘<code class=css>?</code>’ wildcard
2668 characters is five, even though the <a
2669 href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
2670 title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token accepts six.
2672 <p>Within the comma-delimited list of Unicode ranges in a ‘<a
2673 href="#descdef-unicode-range"><code
2674 class=property>unicode-range</code></a>’ descriptor declaration, ranges
2675 may overlap. The union of these ranges defines the set of codepoints for
2676 which the corresponding font may be used. User agents must not download or
2677 use the font for codepoints outside this set. User agents may normalize
2678 the list of ranges into a list that is different but represents the same
2679 set of codepoints.
2681 <p>The associated font might not contain glyphs for the entire set of
2682 codepoints defined by the ‘<a href="#descdef-unicode-range"><code
2683 class=property>unicode-range</code></a>’ descriptor. When the font is
2684 used the effective <a href="#character-map"><em>character map</em></a> is
2685 the intersection of the codepoints defined by ‘<a
2686 href="#descdef-unicode-range"><code
2687 class=property>unicode-range</code></a>’ with the font's <a
2688 href="#character-map"><em>character map</em></a>. This allows authors to
2689 define supported ranges in terms of broad ranges without worrying about
2690 the precise codepoint ranges supported by the underlying font.
2692 <h3 id=composite-fonts><span class=secno>4.6 </span>Using character ranges
2693 to define composite fonts</h3>
2695 <p>Multiple <a href="#at-font-face-rule"><code>@font-face</code></a> rules
2696 with different unicode ranges for the same family and style descriptor
2697 values can be used to create composite fonts that mix the glyphs from
2698 different fonts for different scripts. This can be used to combine fonts
2699 that only contain glyphs for a single script (e.g. Latin, Greek, Cyrillic)
2700 or it can be used by authors as a way of segmenting a font into fonts for
2701 commonly used characters and less frequently used characters. Since the
2702 user agent will only pull down the fonts it needs this helps reduce page
2703 bandwidth.
2705 <p>If the unicode ranges overlap for a set of <a
2706 href="#at-font-face-rule"><code>@font-face</code></a> rules with the same
2707 family and style descriptor values, the rules are ordered in the reverse
2708 order they were defined; the last rule defined is the first to be checked
2709 for a given character.
2711 <p>Example ranges for specific languages or characters:
2713 <dl>
2714 <dt>unicode-range: U+A5;
2716 <dd>a single code point, the yen/yuan symbol
2718 <dt>unicode-range: U+0-7F;
2720 <dd>code range for basic ASCII characters
2722 <dt>unicode-range: U+590-5ff;
2724 <dd>code range for Hebrew characters
2726 <dt>unicode-range: U+A5, U+4E00-9FFF, U+30??, U+FF00-FF9F;
2728 <dd>code range for Japanese kanji, hiragana and katakana characters plus
2729 yen/yuan symbol
2730 </dl>
2732 <div class=example>
2733 <p>The BBC provides news services in a wide variety of languages, many
2734 that are not well supported across all platforms. Using an <a
2735 href="#at-font-face-rule"><code>@font-face</code></a> rule, the BBC could
2736 provide a font for any of these languages, as it already does via a
2737 manual font download.</p>
2739 <pre>
2740 @font-face {
2741 font-family: BBCBengali;
2742 src: url(fonts/BBCBengali.ttf) format("opentype");
2743 unicode-range: U+00-FF, U+980-9FF;
2744 }
2745 </pre>
2746 </div>
2748 <div class=example>
2749 <p>Technical documents often require a wide range of symbols. The STIX
2750 Fonts project is one project aimed at providing fonts to support a wide
2751 range of technical typesetting in a standardized way. The example below
2752 shows the use of a font that provides glyphs for many of the mathematical
2753 and technical symbol ranges within Unicode:</p>
2755 <pre>
2756 @font-face {
2757 font-family: STIXGeneral;
2758 src: local(STIXGeneral), url(/stixfonts/STIXGeneral.otf);
2759 unicode-range: U+000-49F, U+2000-27FF, U+2900-2BFF, U+1D400-1D7FF;
2760 }
2761 </pre>
2762 </div>
2764 <div class=example>
2765 <p>This example shows how an author can override the glyphs used for Latin
2766 characters in a Japanese font with glyphs from a different font. The
2767 first rule specifies no range so it defaults to the entire range. The
2768 range specified in the second rule overlaps but takes precedence because
2769 it is defined later.</p>
2771 <pre>
2772 @font-face {
2773 font-family: JapaneseWithGentium;
2774 src: local(MSMincho);
2775 /* no range specified, defaults to entire range */
2776 }
2778 @font-face {
2779 font-family: JapaneseWithGentium;
2780 src: url(../fonts/Gentium.ttf);
2781 unicode-range: U+0-2FF;
2782 }
2783 </pre>
2784 </div>
2786 <div class=example>
2787 <p>Consider a family constructed to optimize bandwidth by separating out
2788 Latin, Japanese and other characters into different font files:</p>
2790 <pre>
2791 /* fallback font - size: 4.5MB */
2792 @font-face {
2793 font-family: DroidSans;
2794 src: url(DroidSansFallback.ttf);
2795 /* no range specified, defaults to entire range */
2796 }
2798 /* Japanese glyphs - size: 1.2MB */
2799 @font-face {
2800 font-family: DroidSans;
2801 src: url(DroidSansJapanese.ttf);
2802 unicode-range: U+3000-9FFF, U+ff??;
2803 }
2805 /* Latin, Greek, Cyrillic along with some
2806 punctuation and symbols - size: 190KB */
2807 @font-face {
2808 font-family: DroidSans;
2809 src: url(DroidSans.ttf);
2810 unicode-range: U+000-5FF, U+1e00-1fff, U+2000-2300;
2811 }
2812 </pre>
2814 <p>For simple Latin text, only the font for Latin characters is
2815 downloaded:</p>
2817 <pre>
2818 body { font-family: DroidSans; }
2820 <p>This is that</p>
2821 </pre>
2823 <p>In this case the user agent first checks the unicode-range for the font
2824 containing Latin characters (DroidSans.ttf). Since all the characters
2825 above are in the range U+0-5FF, the user agent downloads the font and
2826 renders the text with that font.</p>
2828 <p>Next, consider text that makes use of an arrow character (⇨):</p>
2830 <pre>
2831 <p>This &#x21e8; that<p>
2832 </pre>
2834 <p>The user agent again first checks the unicode-range of the font
2835 containing Latin characters. Since U+2000-2300 includes the arrow code
2836 point (U+21E8), the user agent downloads the font. For this character
2837 however the Latin font does not have a matching glyph, so the effective
2838 unicode-range used for font matching excludes this code point. Next, the
2839 user agent evaluates the Japanese font. The unicode-range for the
2840 Japanese font, U+3000-9FFF and U+ff??, does not include U+21E8, so the
2841 user agent does not download the Japanese font. Next the fallback font is
2842 considered. The <a href="#at-font-face-rule"><code>@font-face</code></a>
2843 rule for the fallback font does not define unicode-range so its value
2844 defaults to the range of all Unicode code points. The fallback font is
2845 downloaded and used to render the arrow character.</p>
2846 </div>
2848 <h3 id=font-rend-desc><span class=secno>4.7 </span>Font features: the <a
2849 href="#descdef-font-variant">font-variant</a> and <a
2850 href="#descdef-font-feature-settings">font-feature-settings</a>
2851 descriptors</h3>
2853 <table class=descdef>
2854 <tbody>
2855 <tr>
2856 <td>Name:
2858 <td><dfn id=descdef-font-variant
2859 title="font-variant!!descriptor">font-variant</dfn>
2861 <tr>
2862 <td>Value:
2864 <td><a href="#font-variant-normal-value"
2865 title="normal!!font-variant">normal</a> | <a
2866 href="#font-variant-none-value" title="none!!font-variant">none</a> | [
2867 <a href="#common-lig-values"><var><common-lig-values></var></a>
2868 || <a
2869 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
2870 || <a
2871 href="#historical-lig-values"><var><historical-lig-values></var></a>
2872 || <a
2873 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
2874 || <a href="#stylistic"><var
2875 title=stylistic>stylistic(<feature-value-name>)</var></a> || <a
2876 href="#historical-forms"><var>historical-forms</var></a> || <a
2877 href="#styleset"><var
2878 title=styleset>styleset(<feature-value-name> #)</var></a> || <a
2879 href="#character-variant"><var
2880 title=character-variant>character-variant(<feature-value-name>
2881 #)</var></a> || <a href="#swash"><var
2882 title=swash>swash(<feature-value-name>)</var></a> || <a
2883 href="#ornaments"><var
2884 title=ornaments>ornaments(<feature-value-name>)</var></a> || <a
2885 href="#annotation"><var
2886 title=annotation>annotation(<feature-value-name>)</var></a> || [
2887 <a href="#small-caps"><i>small-caps</i></a> | <a
2888 href="#all-small-caps"><i>all-small-caps</i></a> | <a
2889 href="#petite-caps"><i>petite-caps</i></a> | <a
2890 href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
2891 href="#unicase"><i>unicase</i></a> | <a
2892 href="#titling-caps"><i>titling-caps</i></a> ] || <a
2893 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
2894 || <a
2895 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
2896 || <a
2897 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
2898 || <a href="#ordinal"><i>ordinal</i></a> || <a
2899 href="#slashed-zero"><i>slashed-zero</i></a> || <a
2900 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
2901 || <a
2902 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
2903 || <a href="#ruby"><i>ruby</i></a> ]
2905 <tr>
2906 <td><em>Initial:</em>
2908 <td>normal
2909 </table>
2911 <table class=descdef>
2912 <tbody>
2913 <tr>
2914 <td>Name:
2916 <td><dfn id=descdef-font-feature-settings
2917 title="font-feature-settings!!descriptor">font-feature-settings</dfn>
2919 <tr>
2920 <td>Value:
2922 <td><a href="#font-feature-settings-normal-value"
2923 title="normal!!font-feature-settings">normal</a> | <a
2924 href="#feature-tag-value"><var><feature-tag-value></var></a> #
2926 <tr>
2927 <td><em>Initial:</em>
2929 <td>normal
2930 </table>
2932 <p>These descriptors define initial settings that apply when the font
2933 defined by an <a href="#at-font-face-rule"><code>@font-face</code></a>
2934 rule is rendered. They do not affect font selection. Values are identical
2935 to those defined for the corresponding <a href="#propdef-font-variant"
2936 title="font-variant!!property">‘<code
2937 class=property>font-variant</code>’</a> and <a
2938 href="#propdef-font-feature-settings"
2939 title="font-feature-settings!!property">‘<code
2940 class=property>font-feature-settings</code>’</a> properties defined
2941 below except that the value ‘<code class=property>inherit</code>’ is
2942 omitted. When multiple font feature descriptors or properties are used,
2943 the cumulative effect on text rendering is detailed in the section <a
2944 href="#font-feature-resolution">Font Feature Resolution</a> below. In
2945 cases where specific values define synthesized fallback for certain <a
2946 href="#propdef-font-variant" title="font-variant!!property">‘<code
2947 class=property>font-variant</code>’</a> subproperties, the same
2948 synthesized fallback applies when used within those values are used with
2949 the <a href="#descdef-font-style" title="font-style!!descriptor">‘<code
2950 class=property>font-variant</code>’</a> descriptor.
2952 <h3 id=font-face-loading><span class=secno>4.8 </span>Font loading
2953 guidelines</h3>
2955 <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule is
2956 designed to allow lazy loading of font resources that are only downloaded
2957 when used within a document. A stylesheet can include <a
2958 href="#at-font-face-rule"><code>@font-face</code></a> rules for a library
2959 of fonts of which only a select set are used; user agents must only
2960 download those fonts that are referred to within the style rules
2961 applicable to a given page. User agents that download all fonts defined in
2962 <a href="#at-font-face-rule"><code>@font-face</code></a> rules without
2963 considering whether those fonts are in fact used within a page are
2964 considered non-conformant. In cases where a font might be downloaded in
2965 character fallback cases, user agents may download a font if it's listed
2966 in a font list but is not actually used for a given text run.
2968 <pre>
2969 @font-face {
2970 font-family: GeometricModern;
2971 src: url(font.ttf);
2972 }
2974 p {
2975 /* font will be downloaded for pages with p elements */
2976 font-family: GeometricModern, sans-serif;
2977 }
2979 h2 {
2980 /* font may be downloaded for pages with h2 elements, even if Futura is available locally */
2981 font-family: Futura, GeometricModern, sans-serif;
2982 }
2983 </pre>
2985 <p>In cases where textual content is loaded before downloadable fonts are
2986 available, user agents may render text as it would be rendered if
2987 downloadable font resources are not available or they may render text
2988 transparently with fallback fonts to avoid a flash of text using a
2989 fallback font. In cases where the font download fails user agents must
2990 display text, simply leaving transparent text is considered non-conformant
2991 behavior. Authors are advised to use fallback fonts in their font lists
2992 that closely match the vertical metrics of the downloadable fonts to avoid
2993 large page reflows where possible.
2995 <h3 id=same-origin-restriction><span class=secno>4.9 </span>Same-origin
2996 restriction for fonts</h3>
2998 <h4 id=default-same-origin-restriction><span class=secno>4.9.1
2999 </span>Default same-origin restriction</h4>
3000 <!-- TPAC 2011 Resolution to require same-origin restriction for loading fonts:
3001 http://lists.w3.org/Archives/Public/www-style/2011Nov/0711.html
3002 http://www.w3.org/2011/10/31-webapps-minutes.html#item02
3003 -->
3005 <p>User agents must implement a same-origin restriction when loading fonts
3006 via the <a href="#at-font-face-rule"><code>@font-face</code></a>
3007 mechanism. This restriction limits the loading of fonts for a given
3008 document to fonts loaded from the same origin. Fonts can only be loaded
3009 via the same host, port, and method combination as the containing
3010 document, using the <a
3011 href="http://www.w3.org/TR/html5/browsers.html#origin">origin matching
3012 algorithm</a> described in the <a href="#HTML5"
3013 rel=biblioentry>[HTML5]<!--{{!HTML5}}--></a> specification. The origin of
3014 the stylesheet containing <a
3015 href="#at-font-face-rule"><code>@font-face</code></a> rules is not used
3016 when deciding whether a font is same origin or not, only the origin of the
3017 containing document is used. The restriction applies to all font types.
3019 <p>Given a document located at http://example.com/page.html, fonts defined
3020 with ‘<a href="#descdef-src"><code class=property>src</code></a>’
3021 definitions considered cross origin must not be loaded:
3023 <pre>
3024 /* same origin (i.e. domain, protocol, port match document) */
3025 src: url(fonts/simple.ttf);
3026 src: url(//fonts/simple.ttf);
3028 /* cross origin, different protocol */
3029 src: url(https://example.com/fonts/simple.ttf);
3031 /* cross origin, different domain */
3032 src: url(http://another.example.com/fonts/simple.ttf);
3033 </pre>
3035 <h4 id=allowing-cross-origin-font-loading><span class=secno>4.9.2
3036 </span>Allowing cross-origin font loading</h4>
3038 <p>User agents must also implement the ability to relax this restriction
3039 using cross-site origin controls <a href="#CORS"
3040 rel=biblioentry>[CORS]<!--{{!CORS}}--></a> for fonts loaded via HTTP.
3041 Sites can explicitly allow cross-site downloading of font data using the
3042 <code>Access-Control-Allow-Origin</code> HTTP header. For other protocols,
3043 no explicit relaxation mechanism is defined or required.
3045 <p>For font loads over HTTP, cross-origin requests must be made with the
3046 following parameter settings which are used in conjunction with the <a
3047 href="http://www.w3.org/TR/cors/#cross-origin-request-0"> <em>cross-origin
3048 request algorithm</em></a> <a href="#CORS"
3049 rel=biblioentry>[CORS]<!--{{!CORS}}--></a>:
3051 <ul>
3052 <li><em>request URL</em> — the URL of the font resource in the <a
3053 href="#descdef-src"><code>src</code></a> descriptor
3055 <li><em>request method</em> — GET
3057 <li><em>author request headers</em> — none
3059 <li><em>request entity body</em> — empty
3061 <li><em>source origin</em> — the origin of the page which linked to the
3062 stylesheet
3064 <li><em>manual redirect flag</em> — false
3066 <li><em>omit credentials flag</em> — true
3068 <li><em>force preflight flag</em> — false
3069 </ul>
3071 <h2 id=font-matching-algorithm><span class=secno>5 </span>Font Matching
3072 Algorithm</h2>
3074 <p>The algorithm below describes how fonts are associated with individual
3075 runs of text. For each character in the run a font family is chosen and a
3076 particular font face is selected containing a glyph for that character.
3078 <h3 id=font-family-casing><span class=secno>5.1 </span>Case sensitivity of
3079 font family names</h3>
3081 <p>As part of the font matching algorithm outlined below, user agents must
3082 match font family names used in style rules with actual font family names
3083 contained in fonts available in a given environment or defined via <a
3084 href="#at-font-face-rule"><code>@font-face</code></a> rules. User agents
3085 must match these names case insensitively, using the "Default Caseless
3086 Matching" algorithm outlined in the Unicode specification <a
3087 href="#UNICODE6" rel=biblioentry>[UNICODE6]<!--{{!UNICODE6}}--></a>. This
3088 algorithm is detailed in section 3.13 entitled "Default Case Algorithms".
3089 Specifically, the algorithm must be applied without normalizing the
3090 strings involved and without applying any language-specific tailorings.
3091 The case folding method specified by this algorithm uses the case mappings
3092 with status field ‘<code class=property>C</code>’ or ‘<code
3093 class=property>F</code>’ in the CaseFolding.txt file of the Unicode
3094 Character Database.
3096 <p class=note> Implementors should take care to verify that a given
3097 caseless string comparison implementation uses this precise algorithm and
3098 not assume that a given platform string matching routine follows it, as
3099 many of these have locale-specific behavior or use some level of string
3100 normalization.
3102 <p class=note> For authors this means that font family names are matched
3103 case insensitively, whether those names exist in a platform font or in the
3104 <a href="#at-font-face-rule"><code>@font-face</code></a> rules contained
3105 in a stylesheet. Authors should take care to ensure that names use a
3106 character sequence consistent with the actual font family name,
3107 particularly when using combining characters such as diacritical marks.
3108 For example, a family name that contains an uppercase A (U+0041) followed
3109 by a combining ring (U+030A) will <strong>not</strong> match a name that
3110 looks identical but which uses the precomposed lowercase a-ring character
3111 (U+00E5) instead of the combining sequence.
3113 <h3 id=font-style-matching><span class=secno>5.2 </span>Matching font
3114 styles</h3>
3116 <p>The procedure for choosing fonts consists of iterating over the font
3117 families determined by the font-family property, selecting a font face
3118 with the appropriate style based on other font properties and then
3119 determining whether a glyph exists for a given character. This is done
3120 using the <dfn id=character-map>character map</dfn> of the font, data
3121 which maps characters to the default glyph for that character. Codepoint
3122 sequences consisting of a base character followed by a sequence of
3123 combining characters are treated slightly differently, see the section on
3124 <a href="#cluster-matching">cluster matching</a> below.
3126 <p>For this procedure, the <dfn id=default-face>default face</dfn> for a
3127 given font family is defined to be the face that would be selected if all
3128 font style properties were set to their initial value.
3130 <ol id=fontmatchingalg>
3131 <li>Using the computed font property values for a given element, the user
3132 agent starts with the first family name in the fontlist specified by the
3133 <a href="#propdef-font-family" title="font-family!!property">‘<code
3134 class=property>font-family</code>’</a> property.
3136 <li>If the family name is unquoted and is a generic family name, the user
3137 agent looks up the appropriate font family name to be used. User agents
3138 may choose the generic font family to use based on the language of the
3139 containing element or the Unicode range of the character.
3141 <li>For other family names, the user agent attempts to find the family
3142 name among fonts defined via <a
3143 href="#at-font-face-rule"><code>@font-face</code></a> rules and then
3144 among available system fonts, matching names with a case-insensitive
3145 comparison as outlined <a href="#font-family-casing">in the section
3146 above</a>. On systems containing fonts with multiple localized font
3147 family names, user agents must match any of these names independent of
3148 the underlying system locale or platform API used. If the font resources
3149 defined for a given face in an <a
3150 href="#at-font-face-rule"><code>@font-face</code></a> rule are either not
3151 available or contain invalid font data, then the face should be treated
3152 as not present in the family. If no faces are present for a family
3153 defined via <a href="#at-font-face-rule"><code>@font-face</code></a>
3154 rules, the family should be treated as missing; matching a platform font
3155 with the same name must not occur in this case.
3157 <li>If a font family match occurs, the user agent assembles the set of
3158 font faces in that family and then narrows the set to a single face using
3159 other font properties in the order given below:
3160 <ol id=fontstylematchingalg>
3161 <li><a href="#propdef-font-stretch"
3162 title="font-stretch!!property">‘<code
3163 class=property>font-stretch</code>’</a> is tried first. If the
3164 matching set contains faces with width values matching the <a
3165 href="#propdef-font-stretch" title="font-stretch!!property">‘<code
3166 class=property>font-stretch</code>’</a> value, faces with other width
3167 values are removed from the matching set. If there is no face that
3168 exactly matches the width value the nearest width is used instead. If
3169 the value of <a href="#propdef-font-stretch"
3170 title="font-stretch!!property">‘<code
3171 class=property>font-stretch</code>’</a> is ‘<a href="#normal"><code
3172 class=property>normal</code></a>’ or one of the condensed values,
3173 narrower width values are checked first, then wider values. If the
3174 value of <a href="#propdef-font-stretch"
3175 title="font-stretch!!property">‘<code
3176 class=property>font-stretch</code>’</a> is one of the expanded
3177 values, wider values are checked first, followed by narrower values.
3178 Once the closest matching width has been determined by this process,
3179 faces with other widths are removed from the matching set.
3181 <li><a href="#propdef-font-style" title="font-style!!property">‘<code
3182 class=property>font-style</code>’</a> is tried next. If the value of
3183 <a href="#propdef-font-style" title="font-style!!property">‘<code
3184 class=property>font-style</code>’</a> is ‘<a href="#italic"><code
3185 class=property>italic</code></a>’, italic faces are checked first,
3186 then oblique, then normal faces. If the value is ‘<a
3187 href="#oblique"><code class=property>oblique</code></a>’, oblique
3188 faces are checked first, then italic faces and then normal faces. If
3189 the value is ‘<a href="#normal"><code
3190 class=property>normal</code></a>’, normal faces are checked first,
3191 then oblique faces, then italic faces. Faces with other style values
3192 are excluded from the matching set. User agents are permitted to
3193 distinguish between italic and oblique faces within platform font
3194 families but this is not required, they may treat all italic or oblique
3195 faces as italic faces. However, within font families defined via <a
3196 href="#at-font-face-rule"><code>@font-face</code></a> rules, italic and
3197 oblique faces must be distinguished using the value of the <a
3198 href="#descdef-font-style" title="font-style!!descriptor">‘<code
3199 class=property>font-style</code>’</a> descriptor.
3201 <li><a href="#propdef-font-weight"
3202 title="font-weight!!property">‘<code
3203 class=property>font-weight</code>’</a> is matched next, it will
3204 always reduce the matching set to a single font face. If bolder/lighter
3205 relative weights are used, the effective weight is calculated based on
3206 the inherited weight value, as described in the definition of the <a
3207 href="#propdef-font-weight" title="font-weight!!property">‘<code
3208 class=property>font-weight</code>’</a> property. Given the desired
3209 weight and the weights of faces in the matching set after the steps
3210 above, if the desired weight is available that face matches. Otherwise,
3211 a weight is chosen using the rules below:
3212 <ul>
3213 <li>If the desired weight is less than 400, weights below the desired
3214 weight are checked in descending order followed by weights above the
3215 desired weight in ascending order until a match is found.
3217 <li>If the desired weight is greater than 500, weights above the
3218 desired weight are checked in ascending order followed by weights
3219 below the desired weight in descending order until a match is found.
3221 <li>If the desired weight is 400, 500 is checked first and then the
3222 rule for desired weights less than 400 is used.
3224 <li>If the desired weight is 500, 400 is checked first and then the
3225 rule for desired weights less than 400 is used.
3226 </ul>
3228 <li><span class=property>‘<a href="#propdef-font-size"><code
3229 class=property>font-size</code></a>’</span> must be matched within a
3230 UA-dependent margin of tolerance. (Typically, sizes for scalable fonts
3231 are rounded to the nearest whole pixel, while the tolerance for
3232 bitmapped fonts could be as large as 20%.) Further computations, e.g.,
3233 by ‘<code class=property>em</code>’ values in other properties, are
3234 based on the <span class=property>‘<a href="#propdef-font-size"><code
3235 class=property>font-size</code></a>’</span> value that is used, not
3236 the one that is specified.
3237 </ol>
3239 <li>
3240 <p>If no matching face exists or the matched face does not contain a
3241 glyph for the character to be rendered, the next family name is selected
3242 and the previous two steps repeated. Glyphs from other faces in the
3243 family are not considered. The only exception is that user agents may
3244 optionally substitute a synthetic version of the <a
3245 href="#default-face"><em>default face</em></a> if that face supports a
3246 given glyph (e.g. a synthetic italic version of the regular face may be
3247 used if the italic face doesn't support glyphs for Arabic).</p>
3248 <!-- resolution on the above: http://lists.w3.org/Archives/Public/www-style/2012Nov/0292.html -->
3250 <p>If the matched font is defined via an <a
3251 href="#at-font-face-rule"><code>@font-face</code></a> rule and needs to
3252 be downloaded, the font resource is downloaded. While the download
3253 occurs, the user agent can either wait until the font is downloaded or
3254 render once with substituted font metrics and render again once the font
3255 is downloaded.</p>
3257 <li>If there are no more font families to be evaluated and no matching
3258 face has been found, then the user agent performs a <em>system font
3259 fallback</em> procedure to find the best match for the character to be
3260 rendered. The result of this procedure may vary across user agents.
3262 <li>If a particular character cannot be displayed using any font, the user
3263 agent should indicate by some means that a character is not being
3264 displayed, displaying either a symbolic representation of the missing
3265 glyph (e.g. using a <a
3266 href="http://en.wikipedia.org/wiki/Last_resort_font">Last Resort
3267 Font</a>) or using the missing character glyph from a default font.
3268 </ol>
3270 <h3 id=cluster-matching><span class=secno>5.3 </span>Cluster matching</h3>
3272 <p>When text contains characters such as combining diacritics, ideally the
3273 base character should be rendered using the same font as the diacritic,
3274 this assures proper placement of the diacritic. For this reason, the font
3275 matching algorithm for clusters is more specialized than the general case
3276 of matching a single character by itself. For sequences containing
3277 variation selectors, which indicate the precise glyph to be used for a
3278 given character, user agents always attempt system font fallback to find
3279 the appropriate glyph before using the default glyph of the base
3280 character.
3282 <p>A font is considered to <em>support</em> a given character if (1) the
3283 character is contained in the font's <a
3284 href="#character-map"><em>character map</em></a> and (2) if required by
3285 the containing script, shaping information is available for that
3286 character. Some legacy fonts may include a given character in the <a
3287 href="#character-map"><em>character map</em></a> but lack the shaping
3288 information (e.g. <a
3289 href="http://www.microsoft.com/typography/otspec/ttochap1.htm">OpenType
3290 layout tables</a> or <a
3291 href="http://scripts.sil.org/cms/scripts/page.php?site_id=projects&item_id=graphite_techAbout">Graphite
3292 tables</a>) necessary for correctly rendering text runs containing that
3293 character.
3295 <p>A sequence of codepoints containing combining diacritics or other
3296 modifiers is termed a grapheme cluster (see <a href="#CSS3TEXT"
3297 rel=biblioentry>[CSS3TEXT]<!--{{CSS3TEXT}}--></a> for a more complete
3298 description). For a given cluster containing a base character, <em>b</em>
3299 and a sequence of combining characters <em>c1, c2…</em>, the entire
3300 cluster is matched using these steps:
3302 <ol>
3303 <li>For each family in the font list, a face is chosen using the style
3304 selection rules defined in the previous section.
3305 <ol>
3306 <li>If all characters in the sequence <em>b + c1 + c2 …</em> are
3307 completely supported by the font, select this font for the sequence.
3309 <li>If a sequence of multiple codepoints is canonically equivalent to a
3310 single character and the font supports that character, select this font
3311 for the sequence.
3312 </ol>
3314 <li>If no font was found in the font list in step 1:
3315 <ol>
3316 <li>If <em>c1</em> is a variation selector, system fallback must be used
3317 to find a font that supports the full sequence of <em>b + c1</em>. If
3318 no font on the system supports the full sequence, match the single
3319 character <em>b</em> using the normal procedure for matching single
3320 characters and ignore the variation selector. Note: a sequence with
3321 more than one variation selector is treated as an encoding error and
3322 the trailing selectors are ignored.
3324 <li>Otherwise, the user agent may optionally use system font fallback to
3325 match a font that supports the entire cluster.
3326 </ol>
3328 <li>If no font is found in step 2, use the matching sequence from step 1
3329 to determine the longest sequence that is completely matched by a font in
3330 the font list and attempt to match the remaining combining characters
3331 separately using the rules for single characters.
3332 </ol>
3334 <h3 id=char-handling-issues><span class=secno>5.4 </span>Character handling
3335 issues</h3>
3337 <p>The procedure above is always performed on text runs containing Unicode
3338 characters, documents using legacy encodings are assumed to have been
3339 transcoded before matching fonts. For fonts containing <a
3340 href="#character-map"><em title="character map">character maps</em></a>
3341 for both legacy encodings and Unicode, the contents of the legacy encoding
3342 <a href="#character-map"><em>character map</em></a> must have no effect on
3343 the results of the font matching process.
3345 <p>The font matching process does not assume that text runs are in either
3346 normalized or denormalized form (see <a href="#CHARMOD-NORM"
3347 rel=biblioentry>[CHARMOD-NORM]<!--{{CHARMOD-NORM}}--></a> for more
3348 details). Layout engines often convert base character plus combining
3349 character sequences into precomposed characters if they exist. The font
3350 matching algorithm outlined here supports both ways and fonts can
3351 generally support either but variations can occur. Authors should always
3352 tailor their choice of fonts to their content, including whether that
3353 content contains normalized or denormalized character streams.
3355 <p>If a given character is a Private-Use Area Unicode codepoint and none of
3356 the fonts in the fontlist contain a glyph for that codepoint, user agents
3357 must display some form of missing glyph symbol for that character rather
3358 than attempting system font fallback for that codepoint. When matching the
3359 replacement character U+FFFD, user agents may skip the font matching
3360 process and immediately display some form of missing glyph symbol, they
3361 are not required to display the glyph from the font that would be selected
3362 by the font matching process.
3364 <p>In general, the fonts for a given family will all have the same or
3365 similar <a href="#character-map"><em title="character map">character
3366 maps</em></a>. The process outlined here is designed to handle even font
3367 families containing faces with widely variant <a href="#character-map"><em
3368 title="character map">character maps</em></a>. However, authors are
3369 cautioned that the use of such families can lead to unexpected results.
3371 <p>Optimizations of this process are allowed provided that an
3372 implementation behaves as if the algorithm had been followed exactly.
3373 Matching occurs in a well-defined order to insure that the results are as
3374 consistent as possible across user agents, given an identical set of
3375 available fonts and rendering technology.
3377 <h3 id=font-matching-changes><span class=secno>5.5 </span>Font matching
3378 changes since CSS 2.1</h3>
3380 <p>The algorithm above is different from CSS 2.1 in a number of key places.
3381 These changes were made to better reflect actual font matching behavior
3382 across user agent implementations.
3384 <p>Differences compared to the font matching algorithm in CSS 2.1:
3386 <ul>
3387 <li>The algorithm includes font-stretch matching.
3389 <li>All possible font-style matching scenarios are delineated.
3391 <li>Small-caps fonts are not matched as part of the font matching process,
3392 they are now handled via font features.
3394 <li>Unicode variation selector matching is required.
3396 <li>Cluster sequences are matched as a unit.
3397 </ul>
3399 <h3 id=font-matching-examples><span class=secno>5.6 </span>Font matching
3400 examples</h3>
3402 <div class=example>
3403 <p>It's useful to note that the CSS selector syntax may be used to create
3404 language-sensitive typography. For example, some Chinese and Japanese
3405 characters are unified to have the same Unicode code point, although the
3406 abstract glyphs are not the same in the two languages.
3408 <pre>*:lang(ja-jp) { font: 900 14pt/16pt "Heisei Mincho W9", serif; }
3409 *:lang(zh-tw) { font: 800 14pt/16.5pt "Li Sung", serif; }
3410 </pre>
3412 <p>This selects any element that has the given language - Japanese or
3413 Traditional Chinese - and uses the appropriate font.
3414 </div>
3416 <h2 id=font-rend-props><span class=secno>6 </span>Font Feature Properties</h2>
3418 <p>Modern font technologies support a variety of advanced typographic and
3419 language-specific font features. Using these features, a single font can
3420 provide glyphs for a wide range of ligatures, contextual and stylistic
3421 alternates, tabular and old-style figures, small capitals, automatic
3422 fractions, swashes, and alternates specific to a given language. To allow
3423 authors control over these font capabilities, the font-variant property
3424 has been expanded for CSS3, it now functions as a shorthand for a set of
3425 properties that provide control over stylistic font features.
3427 <h3 id=glyph-selection-positioning><span class=secno>6.1 </span>Glyph
3428 selection and positioning</h3>
3430 <p>Simple fonts used for displaying Latin text use a very basic processing
3431 model, fonts contain a <a href="#character-map"><em>character map</em></a>
3432 which maps a given character to a glyph for that character. Glyphs for
3433 subsequent characters are simply placed next in line along a run of text.
3434 Font formats such as OpenType and AAT (Apple Advanced Typography) use a
3435 richer processing model, the glyph for a given character can be chosen and
3436 positioned not just based on a single character, but also based on
3437 surrounding characters along with the language, script, and features
3438 enabled for the text. Font features may be required for specific scripts,
3439 or recommended as enabled by default or they may be stylistic features
3440 meant to be used under author control.
3442 <p>For a good visual overview of these features, see the <a
3443 href="#OPENTYPE-FONT-GUIDE"
3444 rel=biblioentry>[OPENTYPE-FONT-GUIDE]<!--{{OPENTYPE-FONT-GUIDE}}--></a>.
3445 For a detailed description of glyph processing for OpenType fonts, see <a
3446 href="#WINDOWS-GLYPH-PROC"
3447 rel=biblioentry>[WINDOWS-GLYPH-PROC]<!--{{WINDOWS-GLYPH-PROC}}--></a>.
3449 <p>Stylistic font features can be classified into two broad categories,
3450 ones that affect the harmonization of glyph shapes with the surrounding
3451 context, such as kerning and ligature features, and those such as the
3452 small-caps, subscript/superscript and alternate features that affect shape
3453 selection.
3455 <p>The subproperties of font-variant listed below are used to control these
3456 stylistic font features; they do not control features that are required
3457 for displaying certain scripts, such as the OpenType features used when
3458 displaying Arabic or Indic language text. They affect glyph selection and
3459 positioning, they do not affect font selection as described in the font
3460 matching section (except in cases required for compatibility with CSS
3461 2.1).
3463 <p>To assure consistent behavior across user agents, the equivalent
3464 OpenType property settings are listed for individual properties and must
3465 be considered normative. When using other font formats these should be
3466 used as a guideline to map CSS font feature property values to specific
3467 font features.
3469 <h3 id=language-specific-support><span class=secno>6.2
3470 </span>Language-specific display</h3>
3472 <p>OpenType also supports language-specific glyph selection and
3473 positioning, so that text can be displayed correctly in cases where the
3474 language dictates a specific display behavior. Languages often share a
3475 common script but the shape of certain letters may vary across those
3476 languages, such as the variations in certain Cyrillic letters used in
3477 Russian and Bulgarian text. In Latin text, it's common to render "fi" with
3478 an explicit fi-ligature that lacks a dot on the "i". However, in languages
3479 such as Turkish which uses both a dotted-i and a dotless-i, it's important
3480 to not use this ligature or use a specialized version that contains a dot
3481 over the "i". The example below shows language-specific variations based
3482 on stylistic traditions found in Spanish, Italian and French orthography:
3484 <div class=featex><img alt="language specific forms, spanish"
3485 src=locl-1.png></div>
3487 <div class=featex><img alt="language specific forms, italian"
3488 src=locl-2.png></div>
3490 <div class=featex><img alt="language specific forms, french"
3491 src=locl-3.png></div>
3493 <p>If the content language of the element is known, according to the rules
3494 of the <a
3495 href="http://www.w3.org/TR/CSS21/conform.html#doclanguage">document
3496 language</a>, user agents are required to infer the OpenType language
3497 system from the content language and use that when selecting and
3498 positioning glyphs using an OpenType font.
3500 <p>For OpenType fonts, in some cases it may be necessary to explicitly
3501 declare the OpenType language to be used, for example when displaying text
3502 in a given language that uses the typographic conventions of another
3503 language or when the font does not explicitly support a given language but
3504 supports a language that shares common typographic conventions. The ‘<a
3505 href="#propdef-font-language-override"><code
3506 class=property>font-language-override</code></a>’ property is used for
3507 this purpose.</p>
3508 <!-- prop: font-kerning -->
3510 <h3 id=font-kerning-prop><span class=secno>6.3 </span>Kerning: the <a
3511 href="#propdef-font-kerning">font-kerning</a> property</h3>
3513 <table class=propdef id=namefont-kerningvalueauto-normal-noneini>
3514 <tbody>
3515 <tr>
3516 <td>Name:
3518 <td><dfn id=propdef-font-kerning>font-kerning</dfn>
3520 <tr>
3521 <td>Value:
3523 <td><a href="#font-kerning-auto-value"
3524 title="auto!!font-kerning">auto</a> | <a
3525 href="#font-kerning-normal-value"
3526 title="normal!!font-kerning">normal</a> | <a
3527 href="#font-kerning-none-value" title="none!!font-kerning">none</a>
3529 <tr>
3530 <td>Initial:
3532 <td>auto
3534 <tr>
3535 <td>Applies to:
3537 <td>all elements
3539 <tr>
3540 <td>Inherited:
3542 <td>yes
3544 <tr>
3545 <td>Percentages:
3547 <td>N/A
3549 <tr>
3550 <td>Media:
3552 <td>visual
3554 <tr>
3555 <td>Computed value:
3557 <td>as specified
3559 <tr>
3560 <td>Animatable:
3562 <td>no
3563 </table>
3565 <p>Kerning is the contextual adjustment of inter-glyph spacing. This
3566 property controls metric kerning, kerning that utilizes adjustment data
3567 contained in the font.
3569 <dl>
3570 <dt><dfn id=font-kerning-auto-value title="auto!!font-kerning">auto</dfn>
3572 <dd>Specifies that kerning is applied at the discretion of the user agent
3574 <dt><dfn id=font-kerning-normal-value
3575 title="normal!!font-kerning">normal</dfn>
3577 <dd>Specifies that kerning is applied
3579 <dt><dfn id=font-kerning-none-value title="none!!font-kerning">none</dfn>
3581 <dd>Specifies that kerning is not applied
3582 </dl>
3584 <p>For fonts that do not include kerning data this property will have no
3585 visible effect. When rendering with OpenType fonts, the <a
3586 href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>
3587 specification suggests that kerning be enabled by default. When kerning is
3588 enabled, the OpenType <span class=tag>kern</span> feature is enabled (for
3589 vertical text runs the <span class=tag>vkrn</span> feature is enabled
3590 instead). User agents must also support fonts that only support kerning
3591 via data contained in a <span class=tag>kern</span> font table, as
3592 detailed in the OpenType specification. If the ‘<code
3593 class=property>letter-spacing</code>’ property is defined, kerning
3594 adjustments are considered part of the default spacing and letter spacing
3595 adjustments are made after kerning has been applied.
3597 <p>When set to ‘<code class=property>auto</code>’, user agents can
3598 determine whether to apply kerning or not based on a number of factors:
3599 text size, script, or other factors that influence text processing speed.
3600 Authors who want proper kerning should use ‘<a href="#normal"><code
3601 class=property>normal</code></a>’ to explicitly enable kerning.
3602 Likewise, some authors may prefer to disable kerning in situations where
3603 performance is more important than precise appearance. However, in
3604 well-designed modern implementations the use of kerning generally does not
3605 have a large impact on text rendering speed.</p>
3606 <!-- prop: font-variant-ligatures -->
3608 <h3 id=font-variant-ligatures-prop><span class=secno>6.4 </span>Ligatures:
3609 the <a href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
3610 property</h3>
3612 <table class=propdef id=namefont-variant-ligaturesvaluenormal-no>
3613 <tbody>
3614 <tr>
3615 <td>Name:
3617 <td><dfn id=propdef-font-variant-ligatures>font-variant-ligatures</dfn>
3619 <tr>
3620 <td>Value:
3622 <td><a href="#font-variant-ligatures-normal-value"
3623 title="normal!!font-variant-ligatures">normal</a> | <a
3624 href="#font-variant-ligatures-none-value"
3625 title="none!!font-variant-ligatures">none</a> | [ <a
3626 href="#common-lig-values"><var><common-lig-values></var></a> ||
3627 <a
3628 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
3629 || <a
3630 href="#historical-lig-values"><var><historical-lig-values></var></a>
3631 || <a
3632 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
3633 ]
3635 <tr>
3636 <td>Initial:
3638 <td>normal
3640 <tr>
3641 <td>Applies to:
3643 <td>all elements
3645 <tr>
3646 <td>Inherited:
3648 <td>yes
3650 <tr>
3651 <td>Percentages:
3653 <td>N/A
3655 <tr>
3656 <td>Media:
3658 <td>visual
3660 <tr>
3661 <td>Computed value:
3663 <td>as specified
3665 <tr>
3666 <td>Animatable:
3668 <td>no
3669 </table>
3671 <p>Ligatures and contextual forms are ways of combining glyphs to produce
3672 more harmonized forms.
3674 <pre
3675 class=prod><dfn id=common-lig-values><var><common-lig-values></var></dfn> = [ <a href="#common-ligatures">common-ligatures</a> | <a href="#no-common-ligatures">no-common-ligatures</a> ]</pre>
3677 <pre
3678 class=prod><dfn id=discretionary-lig-values><var><discretionary-lig-values></var></dfn> = [ <a href="#discretionary-ligatures">discretionary-ligatures</a> | <a href="#no-discretionary-ligatures">no-discretionary-ligatures</a> ]</pre>
3680 <pre
3681 class=prod><dfn id=historical-lig-values><var><historical-lig-values></var></dfn> = [ <a href="#historical-ligatures">historical-ligatures</a> | <a href="#no-historical-ligatures">no-historical-ligatures</a> ]</pre>
3683 <pre
3684 class=prod><dfn id=contextual-alt-values><var><contextual-alt-values></var></dfn> = [ <a href="#contextual">contextual</a> | <a href="#no-contextual">no-contextual</a> ]</pre>
3686 <p>Individual values have the following meanings:
3688 <dl>
3689 <dt><dfn id=font-variant-ligatures-normal-value
3690 title="normal!!font-variant-ligatures">normal</dfn>
3692 <dd>A value of ‘<a href="#normal"><code
3693 class=property>normal</code></a>’ specifies that common default
3694 features are enabled, <a href="#font-feature-resolution">as described in
3695 detail in the next section</a>. For OpenType fonts, common ligatures and
3696 contextual forms are on by default, discretionary and historical
3697 ligatures are not.
3699 <dt><dfn id=font-variant-ligatures-none-value
3700 title="none!!font-variant-ligatures">none</dfn>
3702 <dd>Specifies that all types of ligatures and contextual forms covered by
3703 this property are explicitly disabled. In situations where ligatures are
3704 not considered necessary, this may improve the speed of text rendering.
3706 <dt><dfn id=common-ligatures>common-ligatures</dfn>
3708 <dd>Enables display of common ligatures (OpenType features: <span
3709 class=tag>liga, clig</span>). For OpenType fonts, common ligatures are
3710 enabled by default.
3711 </dl>
3713 <div class=featex><img alt="common ligature example" src=liga.png></div>
3715 <dl>
3716 <dt><dfn id=no-common-ligatures>no-common-ligatures</dfn>
3718 <dd>Disables display of common ligatures (OpenType features: <span
3719 class=tag>liga, clig</span>).
3721 <dt><dfn id=discretionary-ligatures>discretionary-ligatures</dfn>
3723 <dd>Enables display of discretionary ligatures (OpenType feature: <span
3724 class=tag>dlig</span>). Which ligatures are discretionary or optional is
3725 decided by the type designer, so authors will need to refer to the
3726 documentation of a given font to understand which ligatures are
3727 considered discretionary.
3728 </dl>
3730 <div class=featex><img alt="discretionary ligature example" src=dlig.png></div>
3732 <dl>
3733 <dt><dfn id=no-discretionary-ligatures>no-discretionary-ligatures</dfn>
3735 <dd>Disables display of discretionary ligatures (OpenType feature: <span
3736 class=tag>dlig</span>).
3738 <dt><dfn id=historical-ligatures>historical-ligatures</dfn>
3740 <dd>Enables display of historical ligatures (OpenType feature: <span
3741 class=tag>hlig</span>).
3742 </dl>
3744 <div class=featex><img alt="historical ligature example" src=hlig.png></div>
3746 <dl>
3747 <dt><dfn id=no-historical-ligatures>no-historical-ligatures</dfn>
3749 <dd>Disables display of historical ligatures (OpenType feature: <span
3750 class=tag>hlig</span>).
3752 <dt><dfn id=contextual>contextual</dfn>
3754 <dd>Enables display of contextual alternates (OpenType feature: <span
3755 class=tag>calt</span>). Although not strictly a ligature feature, like
3756 ligatures this feature is commonly used to harmonize the shapes of glyphs
3757 with the surrounding context. For OpenType fonts, this feature is on by
3758 default.
3759 </dl>
3761 <div class=featex><img alt="contextual alternate example" src=calt.png></div>
3763 <dl>
3764 <dt><dfn id=no-contextual>no-contextual</dfn>
3766 <dd>Disables display of contextual alternates (OpenType feature: <span
3767 class=tag>calt</span>).
3768 </dl>
3770 <p>Required ligatures, needed for correctly rendering complex scripts, are
3771 not affected by the settings above, including ‘<code
3772 class=property>none</code>’ (OpenType feature: <span
3773 class=tag>rlig</span>).</p>
3774 <!-- prop: font-variant-position -->
3776 <h3 id=font-variant-position-prop><span class=secno>6.5 </span>Subscript
3777 and superscript forms: the <a
3778 href="#propdef-font-variant-position">font-variant-position</a> property</h3>
3780 <table class=propdef id=namefont-variant-positionvaluenormal-sub>
3781 <tbody>
3782 <tr>
3783 <td>Name:
3785 <td><dfn id=propdef-font-variant-position>font-variant-position</dfn>
3787 <tr>
3788 <td>Value:
3790 <td><span title="normal!!font-variant-position">normal</span> | <a
3791 href="#sub">sub</a> | <a href="#super">super</a>
3793 <tr>
3794 <td>Initial:
3796 <td>normal
3798 <tr>
3799 <td>Applies to:
3801 <td>all elements
3803 <tr>
3804 <td>Inherited:
3806 <td>yes
3808 <tr>
3809 <td>Percentages:
3811 <td>N/A
3813 <tr>
3814 <td>Media:
3816 <td>visual
3818 <tr>
3819 <td>Computed value:
3821 <td>as specified
3823 <tr>
3824 <td>Animatable:
3826 <td>no
3827 </table>
3829 <p>This property is used to enable typographic subscript and superscript
3830 glyphs. These are alternate glyphs designed within the same em-box as
3831 default glyphs and are intended to be laid out on the same baseline as the
3832 default glyphs, with no resizing or repositioning of the baseline. They
3833 are explicitly designed to match the surrounding text and to be more
3834 readable without affecting the line height.
3836 <div class=figure><img alt="comparison between real subscript glyphs and
3837 synthesized ones" src=realsubscripts.png>
3838 <p class=caption>Subscript glyphs (top) vs. typical synthesized subscripts
3839 (bottom)
3840 </div>
3842 <p>Individual values have the following meanings:
3844 <dl>
3845 <dt><dfn id=normal>normal</dfn>
3847 <dd>None of the features listed below are enabled.
3849 <dt><dfn id=sub>sub</dfn>
3851 <dd>Enables display of subscript variants (OpenType feature: <span
3852 class=tag>subs</span>).
3854 <dt><dfn id=super>super</dfn>
3856 <dd>Enables display of superscript variants (OpenType feature: <span
3857 class=tag>sups</span>).
3858 </dl>
3860 <p>Because of the semantic nature of subscripts and superscripts, when the
3861 value is either ‘<a href="#sub"><code class=property>sub</code></a>’
3862 or ‘<a href="#super"><code class=property>super</code></a>’ for a
3863 given contiguous run of text, if a variant glyph is not available for all
3864 the characters in the run, simulated glyphs must be synthesized for all
3865 characters using reduced forms of the glyphs that would be used without
3866 this feature applied. This is done per run to avoid a mixture of variant
3867 glyphs and synthesized ones that would not align correctly. In the case of
3868 OpenType fonts that lack subscript or superscript glyphs for a given
3869 character, user agents must use the appropriate subscript and superscript
3870 metrics specified in the selected font's <a
3871 href="http://www.microsoft.com/typography/otspec/os2.htm#subxs">OS/2
3872 table</a> <a href="#OPENTYPE"
3873 rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> to calculate the size
3874 and offset of the synthesized substitutes.
3876 <div class=figure><img alt="alternate superscripts vs. glyphs synthesized
3877 using superscript metrics" src=superscript-alt-synth.png>
3878 <p class=caption>Superscript alternate glyph (left), synthesized
3879 superscript glyphs (middle), and incorrect mixture of the two (right)
3880 </div>
3882 <p>In the past, user agents have used font-size and vertical-align to
3883 simulate subscripts and superscripts for the <a class=tag
3884 href="#sub">sub</a> and <span class=tag>sup</span> elements. To allow a
3885 backwards compatible way of defining subscripts and superscripts, it is
3886 recommended that authors use conditional rules <a href="#CSS3-CONDITIONAL"
3887 rel=biblioentry>[CSS3-CONDITIONAL]<!--{{CSS3-CONDITIONAL}}--></a> so that
3888 older user agents will still render subscripts and superscripts via the
3889 older mechanism.
3891 <p>Authors should note that fonts typically only provide subscript and
3892 superscript glyphs for a subset of all characters supported by the font.
3893 For example, while subscript and superscript glyphs are often available
3894 for Latin numbers, glyphs for punctuation and letter characters are less
3895 frequently provided. The synthetic fallback rules defined for this
3896 property assure that subscripts and superscripts will always appear but
3897 the appearance may not match author expectations if the font used does not
3898 provide the appropriate alternate glyph for all characters contained in a
3899 subscript or superscript.
3901 <p>This property is not cumulative. Applying it to elements within a
3902 subscript or superscript won't nest the placement of a subscript or
3903 superscript glyph. Images contained within text runs where the value of
3904 this property is ‘<a href="#sub"><code class=property>sub</code></a>’
3905 or ‘<a href="#super"><code class=property>super</code></a>’ will be
3906 drawn just as they would if the value was ‘<a href="#normal"><code
3907 class=property>normal</code></a>’. Likewise, text decorations such as
3908 underlines or emphasis marks will render in the same position as they
3909 would for the default glyphs, since this property does not affect the
3910 baseline position.
3912 <p class=issue>Some have suggested that text decorations should apply to
3913 the visual baseline of the variant glyphs, rather than the baseline
3914 defined by the font.
3916 <p>Because of these limitations, ‘<a
3917 href="#propdef-font-variant-position"><code
3918 class=property>font-variant-position</code></a>’ is not recommended for
3919 use in user agent stylesheets. Authors should use it in cases where
3920 subscripts or superscripts will only contain the narrow range of
3921 characters supported by the fonts specified.
3923 <div class=example>
3924 <p>A typical user agent default style for the <a class=tag
3925 href="#sub">sub</a> element:</p>
3927 <pre>sub {
3928 vertical-align: sub;
3929 font-size: smaller;
3930 line-height: normal;
3931 }
3932 </pre>
3934 <p>Using font-variant-position to specify typographic subscripts in a way
3935 that will still show subscripts in older user agents:</p>
3937 <pre>@supports ( font-variant-position: sub ) {
3939 sub {
3940 vertical-align: baseline;
3941 font-size: 100%;
3942 line-height: inherit;
3943 font-variant-position: sub;
3944 }
3946 }
3947 </pre>
3949 <p>User agents that support the ‘<a
3950 href="#propdef-font-variant-position"><code
3951 class=property>font-variant-position</code></a>’ property will select a
3952 subscript variant glyph and render this without adjusting the baseline or
3953 font-size. Older user agents will ignore the ‘<a
3954 href="#propdef-font-variant-position"><code
3955 class=property>font-variant-position</code></a>’ property definition
3956 and use the standard defaults for subscripts.</p>
3957 </div>
3958 <!-- prop: font-variant-caps -->
3960 <h3 id=font-variant-caps-prop><span class=secno>6.6 </span>Capitalization:
3961 the <a href="#propdef-font-variant-caps">font-variant-caps</a> property</h3>
3963 <table class=propdef id=namefont-variant-capsvaluenormal-small-c>
3964 <tbody>
3965 <tr>
3966 <td>Name:
3968 <td><dfn id=propdef-font-variant-caps>font-variant-caps</dfn>
3970 <tr>
3971 <td>Value:
3973 <td><a href="#font-variant-caps-normal-value"
3974 title="normal!!font-variant-caps">normal</a> | <a
3975 href="#small-caps">small-caps</a> | <a
3976 href="#all-small-caps">all-small-caps</a> | <a
3977 href="#petite-caps">petite-caps</a> | <a
3978 href="#all-petite-caps">all-petite-caps</a> | <a
3979 href="#unicase">unicase</a> | <a href="#titling-caps">titling-caps</a>
3981 <tr>
3982 <td>Initial:
3984 <td>normal
3986 <tr>
3987 <td>Applies to:
3989 <td>all elements
3991 <tr>
3992 <td>Inherited:
3994 <td>yes
3996 <tr>
3997 <td>Percentages:
3999 <td>N/A
4001 <tr>
4002 <td>Media:
4004 <td>visual
4006 <tr>
4007 <td>Computed value:
4009 <td>as specified
4011 <tr>
4012 <td>Animatable:
4014 <td>no
4015 </table>
4017 <p>This property allows the selection of alternate glyphs used for small or
4018 petite capitals or for titling. These glyphs are specifically designed to
4019 blend well with the surrounding normal glyphs, to maintain the weight and
4020 readability which suffers when text is simply resized to fit this purpose.
4022 <p>Individual values have the following meanings:
4024 <dl>
4025 <dt><dfn id=font-variant-caps-normal-value
4026 title="normal!!font-variant-caps">normal</dfn>
4028 <dd>None of the features listed below are enabled.
4030 <dt><dfn id=small-caps>small-caps</dfn>
4032 <dd>Enables display of small capitals (OpenType feature: <span
4033 class=tag>smcp</span>). Small-caps glyphs typically use the form of
4034 uppercase letters but are reduced to the size of lowercase letters.
4035 </dl>
4037 <div class=featex><img alt="small-caps example" src=smcp.png></div>
4039 <dl>
4040 <dt><dfn id=all-small-caps>all-small-caps</dfn>
4042 <dd>Enables display of small capitals for both upper and lowercase letters
4043 (OpenType features: <span class=tag>c2sc, smcp</span>).
4045 <dt><dfn id=petite-caps>petite-caps</dfn>
4047 <dd>Enables display of petite capitals (OpenType feature: <span
4048 class=tag>pcap</span>).
4050 <dt><dfn id=all-petite-caps>all-petite-caps</dfn>
4052 <dd>Enables display of petite capitals for both upper and lowercase
4053 letters (OpenType features: <span class=tag>c2pc, pcap</span>).
4055 <dt><dfn id=unicase>unicase</dfn>
4057 <dd>Enables display of mixture of small capitals for uppercase letters
4058 with normal lowercase letters (OpenType feature: <span
4059 class=tag>unic</span>).
4061 <dt><dfn id=titling-caps>titling-caps</dfn>
4063 <dd>Enables display of titling capitals (OpenType feature: <span
4064 class=tag>titl</span>). Uppercase letter glyphs are often designed for
4065 use with lowercase letters. When used in all uppercase titling sequences
4066 they can appear too strong. Titling capitals are designed specifically
4067 for this situation.
4068 </dl>
4070 <p>The availability of these glyphs is based on whether a given feature is
4071 defined or not in the feature list of the font. User agents can optionally
4072 decide this on a per-script basis but should explicitly not decide this on
4073 a per-character basis.
4075 <p>Some fonts may only support a subset or none of the features described
4076 for this property. For backwards compatibility with CSS 2.1, if ‘<a
4077 href="#small-caps"><code class=property>small-caps</code></a>’ or ‘<a
4078 href="#all-small-caps"><code class=property>all-small-caps</code></a>’
4079 is specified but small-caps glyphs are not available for a given font,
4080 user agents should simulate a small-caps font, for example by taking a
4081 normal font and replacing the glyphs for lowercase letters with scaled
4082 versions of the glyphs for uppercase characters (replacing the glyphs for
4083 both upper and lowercase letters in the case of ‘<a
4084 href="#all-small-caps"><code class=property>all-small-caps</code></a>’).
4086 <div class=figure style="padding: 0; margin: auto;"><img alt="synthetic vs.
4087 real small-caps" class=hires src=synthetic-vs-real-small-caps.png
4088 width=512px>
4089 <p class=caption>Synthetic vs. real small-caps
4090 </div>
4092 <p>To match the surrounding text, a font may provide alternate glyphs for
4093 caseless characters when these features are enabled but when a user agent
4094 simulates small capitals, it must not attempt to simulate alternates for
4095 codepoints which are considered caseless.
4097 <div class=figure style="padding: 0; margin: auto;"><img alt="caseless
4098 characters with small-caps, all-small-caps enabled" class=hires
4099 src=small-capitals-variations.png width=418px>
4100 <p class=caption>Caseless characters with small-caps, all-small-caps
4101 enabled
4102 </div>
4104 <p>If either ‘<a href="#petite-caps"><code
4105 class=property>petite-caps</code></a>’ or ‘<a
4106 href="#all-petite-caps"><code class=property>all-petite-caps</code></a>’
4107 is specified for a font that doesn't support these features, the property
4108 behaves as if ‘<a href="#small-caps"><code
4109 class=property>small-caps</code></a>’ or ‘<a
4110 href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
4111 respectively, had been specified. If ‘<a href="#unicase"><code
4112 class=property>unicase</code></a>’ is specified for a font that doesn't
4113 support that feature, the property behaves as if ‘<a
4114 href="#small-caps"><code class=property>small-caps</code></a>’ was
4115 applied only to lowercased uppercase letters. If ‘<a
4116 href="#titling-caps"><code class=property>titling-caps</code></a>’ is
4117 specified with a font that does not support this feature, this property
4118 has no visible effect. When simulated small capital glyphs are used, for
4119 scripts that lack uppercase and lowercase letters, ‘<a
4120 href="#small-caps"><code class=property>small-caps</code></a>’, ‘<a
4121 href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
4122 ‘<a href="#petite-caps"><code class=property>petite-caps</code></a>’,
4123 ‘<a href="#all-petite-caps"><code
4124 class=property>all-petite-caps</code></a>’ and ‘<a
4125 href="#unicase"><code class=property>unicase</code></a>’ have no visible
4126 effect.
4128 <p>When casing transforms are used to simulate small capitals, the casing
4129 transformations must match those used for the <span
4130 class=property>‘<code class=property>text-transform</code>’</span>
4131 property.
4133 <p>As a last resort, unscaled uppercase letter glyphs in a normal font may
4134 replace glyphs in a small-caps font so that the text appears in all
4135 uppercase letters.
4137 <div class=figure style="padding: 0; margin: auto;"><img alt="using
4138 all-small-caps in acronym-laden text" class=hires
4139 src=acronym-laden-text.png width=596px>
4140 <p class=caption>Using small capitals to improve readability in
4141 acronym-laden text
4142 </div>
4144 <div class=example>
4145 <p>Quotes rendered italicised, with small-caps on the first line:</p>
4147 <pre>blockquote { font-style: italic; }
4148 blockquote:first-line { font-variant: small-caps; }
4150 <blockquote><a href="http://lists.w3.org/Archives/Public/www-style/2009Dec/0036.html" style="text-decoration: none">I'll be honor-bound to slap them like a haddock.</a></blockquote>
4151 </pre>
4152 </div>
4153 <!-- prop: font-variant-numeric -->
4155 <h3 id=font-variant-numeric-prop><span class=secno>6.7 </span>Numerical
4156 formatting: the <a
4157 href="#propdef-font-variant-numeric">font-variant-numeric</a> property</h3>
4159 <table class=propdef id=namefont-variant-numericvaluenormal-ltnu>
4160 <tbody>
4161 <tr>
4162 <td>Name:
4164 <td><dfn id=propdef-font-variant-numeric>font-variant-numeric</dfn>
4166 <tr>
4167 <td>Value:
4169 <td><a href="#font-variant-numeric-normal-value"
4170 title="normal!!font-variant-numeric">normal</a> | [ <a
4171 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
4172 || <a
4173 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
4174 || <a
4175 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
4176 || <a href="#ordinal">ordinal</a> || <a
4177 href="#slashed-zero">slashed-zero</a> ]
4179 <tr>
4180 <td>Initial:
4182 <td>normal
4184 <tr>
4185 <td>Applies to:
4187 <td>all elements
4189 <tr>
4190 <td>Inherited:
4192 <td>yes
4194 <tr>
4195 <td>Percentages:
4197 <td>N/A
4199 <tr>
4200 <td>Media:
4202 <td>visual
4204 <tr>
4205 <td>Computed value:
4207 <td>as specified
4209 <tr>
4210 <td>Animatable:
4212 <td>no
4213 </table>
4215 <p>Specifies control over numerical forms. The example below shows how some
4216 of these values can be combined to influence the rendering of tabular data
4217 with fonts that support these features. Within normal paragraph text,
4218 proportional numbers are used while tabular numbers are used so that
4219 columns of numbers line up properly:
4221 <div class=figure style="padding: 0; margin: auto;"><img alt="combining
4222 number styles" src=numberstyles.png>
4223 <p class=caption>Using number styles
4224 </div>
4226 <p>Possible combinations:
4228 <pre
4229 class=prod><dfn id=numeric-figure-values><var><numeric-figure-values></var></dfn> = [ <a href="#lining-nums">lining-nums</a> | <a href="#oldstyle-nums">oldstyle-nums</a> ]</pre>
4231 <pre
4232 class=prod><dfn id=numeric-spacing-values><var><numeric-spacing-values></var></dfn> = [ <a href="#proportional-nums">proportional-nums</a> | <a href="#tabular-nums">tabular-nums</a> ]</pre>
4234 <pre
4235 class=prod><dfn id=numeric-fraction-values><var><numeric-fraction-values></var></dfn> = [ <a href="#diagonal-fractions">diagonal-fractions</a> | <a href="#stacked-fractions">stacked-fractions</a> ]</pre>
4237 <p>Individual values have the following meanings:
4239 <dl>
4240 <dt><dfn id=font-variant-numeric-normal-value
4241 title="normal!!font-variant-numeric">normal</dfn>
4243 <dd>None of the features listed below are enabled.
4245 <dt><dfn id=lining-nums>lining-nums</dfn>
4247 <dd>Enables display of lining numerals (OpenType feature: <span
4248 class=tag>lnum</span>).
4250 <dt><dfn id=oldstyle-nums>oldstyle-nums</dfn>
4252 <dd>Enables display of old-style numerals (OpenType feature: <span
4253 class=tag>onum</span>).
4255 <dt><dfn id=proportional-nums>proportional-nums</dfn>
4257 <dd>Enables display of proportional numerals (OpenType feature: <span
4258 class=tag>pnum</span>).
4260 <dt><dfn id=tabular-nums>tabular-nums</dfn>
4262 <dd>Enables display of tabular numerals (OpenType feature: <span
4263 class=tag>tnum</span>).
4265 <dt><dfn id=diagonal-fractions>diagonal-fractions</dfn>
4267 <dd>Enables display of lining diagonal fractions (OpenType feature: <span
4268 class=tag>frac</span>).
4269 </dl>
4271 <div class=featex><img alt="diagonal fraction example" src=frac.png></div>
4273 <dl>
4274 <dt><dfn id=stacked-fractions>stacked-fractions</dfn>
4276 <dd>Enables display of lining stacked fractions (OpenType feature: <span
4277 class=tag>afrc</span>).
4278 </dl>
4280 <div class=featex><img alt="stacked fraction example" src=afrc.png></div>
4282 <dl>
4283 <dt><dfn id=ordinal>ordinal</dfn>
4285 <dd>Enables display of forms used with ordinal numbers (OpenType feature:
4286 <span class=tag>ordn</span>).
4288 <dt><dfn id=slashed-zero>slashed-zero</dfn>
4290 <dd>Enables display of slashed zeros (OpenType feature: <span
4291 class=tag>zero</span>).
4292 </dl>
4294 <div class=featex><img alt="slashed zero example" src=zero.png></div>
4296 <div class=example id=steak-marinade>
4297 <p>A simple flank steak marinade recipe, rendered with automatic fractions
4298 and old-style numerals:</p>
4300 <pre>.amount { font-variant-numeric: oldstyle-nums diagonal-fractions; }
4302 <h4>Steak marinade:</h4>
4303 <ul>
4304 <li><span class="amount">2</span> tbsp olive oil</li>
4305 <li><span class="amount">1</span> tbsp lemon juice</li>
4306 <li><span class="amount">1</span> tbsp soy sauce</li>
4307 <li><span class="amount">1 1/2</span> tbsp dry minced onion</li>
4308 <li><span class="amount">2 1/2</span> tsp italian seasoning</li>
4309 <li>Salt &amp; pepper</li>
4310 </ul>
4312 <p>Mix the meat with the marinade and let it sit covered in the refrigerator
4313 for a few hours or overnight.</p>
4314 </pre>
4316 <p>Note that the fraction feature is only applied to values not the entire
4317 paragraph. Fonts often implement this feature using contextual rules
4318 based on the use of the slash (‘<code class=css>/</code>’) character.
4319 As such, it's not suitable for use as a paragraph-level style.</p>
4320 </div>
4321 <!-- prop: font-variant-alternates -->
4323 <h3 id=font-variant-alternates-prop><span class=secno>6.8 </span>Alternates
4324 and swashes: the <a
4325 href="#propdef-font-variant-alternates">font-variant-alternates</a>
4326 property</h3>
4328 <table class=propdef id=namefont-variant-alternatesvaluenormal-s>
4329 <tbody>
4330 <tr>
4331 <td>Name:
4333 <td><dfn
4334 id=propdef-font-variant-alternates>font-variant-alternates</dfn>
4336 <tr>
4337 <td>Value:
4339 <td>normal | [ <a href="#stylistic"
4340 title=stylistic>stylistic(<feature-value-name>)</a> || <a
4341 href="#historical-forms">historical-forms</a> || <a href="#styleset"
4342 title=styleset>styleset(<feature-value-name> #)</a> || <a
4343 href="#character-variant"
4344 title=character-variant>character-variant(<feature-value-name>
4345 #)</a> || <a href="#swash"
4346 title=swash>swash(<feature-value-name>)</a> || <a
4347 href="#ornaments"
4348 title=ornaments>ornaments(<feature-value-name>)</a> || <a
4349 href="#annotation"
4350 title=annotation>annotation(<feature-value-name>)</a> ]
4352 <tr>
4353 <td>Initial:
4355 <td>normal
4357 <tr>
4358 <td>Applies to:
4360 <td>all elements
4362 <tr>
4363 <td>Inherited:
4365 <td>yes
4367 <tr>
4368 <td>Percentages:
4370 <td>N/A
4372 <tr>
4373 <td>Media:
4375 <td>visual
4377 <tr>
4378 <td>Computed value:
4380 <td>as specified
4382 <tr>
4383 <td>Animatable:
4385 <td>no
4386 </table>
4388 <p>For any given character, fonts can provide a variety of alternate glyphs
4389 in addition to the default glyph for that character. This property
4390 provides control over the selection of these alternate glyphs.
4392 <p>For many of the property values listed below, several different
4393 alternate glyphs are available. How many alternates are available and what
4394 they represent is font-specific, so these are each marked <em>font
4395 specific</em> in the value definitions below. Because the nature of these
4396 alternates is font-specific, the <a
4397 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
4398 rule is used to define values for a specific font family or set of
4399 families that associate a font-specific numeric
4400 <code><feature-index></code> with a custom
4401 <code><feature-value-name></code>, which is then used in this
4402 property to select specific alternates:
4404 <pre>@font-feature-values Noble Script { @swash { swishy: 1; flowing: 2; } }
4406 p {
4407 font-family: Noble Script;
4408 font-variant-alternates: swash(flowing); /* use swash alternate #2 */
4409 }</pre>
4411 <p>When a particular <code><feature-value-name></code> has not been
4412 defined for a given family or for a particular feature type, the computed
4413 value must be the same as if it had been defined. However, property values
4414 that contain these undefined <code><feature-value-name></code>
4415 identifiers must be ignored when choosing glyphs.
4417 <pre>/* these two style rules are effectively the same */
4418 p { font-variant-alternates: swash(unknown-value); } /* not a defined value, ignored */
4419 p { font-variant-alternates: normal; }
4420 </pre>
4422 <p>This allows values to be defined and used for a given set of font
4423 families but ignored if fallback occurs, since the font family name would
4424 be different. If a given value is outside the range supported by a given
4425 font, the value is ignored. These values never apply to generic font
4426 families.
4428 <p>Individual values have the following meanings:
4430 <dl>
4431 <dt><dfn id=font-variant-alternates-normal-value
4432 title="normal!!font-variant-alternates">normal</dfn>
4434 <dd>None of the features listed below are enabled.
4436 <dt><dfn id=historical-forms>historical-forms</dfn>
4438 <dd>Enables display of historical forms (OpenType feature: <span
4439 class=tag>hist</span>).
4440 </dl>
4442 <div class=featex><img alt="historical form example" src=hist.png></div>
4444 <dl>
4445 <dt><dfn id=stylistic
4446 title=stylistic>stylistic(<feature-value-name>)</dfn>
4448 <dd>Enables display of stylistic alternates (<em>font specific</em>,
4449 OpenType feature: <span class=tag>salt <feature-index></span>).
4450 </dl>
4452 <div class=featex><img alt="stylistic alternate example" src=salt.png></div>
4454 <dl>
4455 <dt><dfn id=styleset title=styleset>styleset(<feature-value-name>
4456 #)</dfn>
4458 <dd>Enables display with stylistic sets (<em>font specific</em>, OpenType
4459 feature: <span class=tag>ss<feature-index></span> OpenType
4460 currently defines <span class=tag>ss01</span> through <span
4461 class=tag>ss20</span>).
4462 </dl>
4464 <div class=featex><img alt="styleset example" src=ssnn.png></div>
4466 <dl>
4467 <dt><dfn id=character-variant
4468 title=character-variant>character-variant(<feature-value-name>
4469 #)</dfn>
4471 <dd>Enables display of specific character variants (<em>font
4472 specific</em>, OpenType feature: <span
4473 class=tag>cv<feature-index></span> OpenType currently defines <span
4474 class=tag>cv01</span> through <span class=tag>cv99</span>).
4476 <dt><dfn id=swash title=swash>swash(<feature-value-name>)</dfn>
4478 <dd>Enables display of swash glyphs (<em>font specific</em>, OpenType
4479 feature: <span class=tag>swsh <feature-index>, cswh
4480 <feature-index></span>).
4481 </dl>
4483 <div class=featex><img alt="swash example" src=swsh.png></div>
4485 <dl>
4486 <dt><dfn id=ornaments
4487 title=ornaments>ornaments(<feature-value-name>)</dfn>
4489 <dd>Enables replacement of default glyphs with ornaments, if provided in
4490 the font (<em>font specific</em>, OpenType feature: <span class=tag>ornm
4491 <feature-index></span>). Some fonts may offer ornament glyphs as
4492 alternates for a wide collection of characters; however, displaying
4493 arbitrary characters (e.g., alphanumerics) as ornaments is poor practice
4494 as it distorts the semantics of the data. Font designers are encouraged
4495 to encode all ornaments (except those explicitly encoded in the Unicode
4496 Dingbats blocks, etc.) as alternates for the bullet character (U+2022) to
4497 allow authors to select the desired glyph using ‘<a
4498 href="#ornaments"><code class=property>ornaments</code></a>’.
4499 </dl>
4501 <div class=featex><img alt="ornaments example" src=ornm.png></div>
4503 <dl>
4504 <dt><dfn id=annotation
4505 title=annotation>annotation(<feature-value-name>)</dfn>
4507 <dd>Enables display of alternate annotation forms (<em>font specific</em>,
4508 OpenType feature: <span class=tag>nalt <feature-index></span>).
4509 </dl>
4511 <div class=featex><img alt="alternate annotation form example"
4512 src=nalt.png></div>
4514 <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
4515 specific alternates: the <dfn id=at-font-feature-values-rule
4516 style="font-weight: inherit; font-style:
4517 inherit"><code>@font-feature-values</code></dfn> rule</h3>
4519 <p>Several of the possible values of ‘<a
4520 href="#propdef-font-variant-alternates"><code
4521 class=property>font-variant-alternates</code></a>’ listed above are
4522 labeled as "font specific". For these features fonts may define not just a
4523 single glyph but a set of alternate glyphs with an index to select a given
4524 alternate. Since these are font family specific, the <a
4525 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
4526 rule is used to define named-values for these indices for a given family.
4528 <p>In the case of the swash Q in the example shown above, the swash could
4529 be specified using these style rules:
4531 <pre>
4533 @font-feature-values Jupiter Sans {
4534 @swash {
4535 delicate: 1;
4536 flowing: 2;
4537 }
4538 }
4540 h2 { font-family: Jupiter Sans, sans-serif; }
4542 /* show the second swash variant in h2 headings */
4543 h2:first-letter { font-variant-alternates: swash(flowing); }
4545 <h2>Quick</h2></pre>
4547 <p>When Jupiter Sans is present, the second alternate swash alternate will
4548 be displayed. When not present, no swash character will be shown, since
4549 the specific named-value "flowing" is only defined for the Jupiter Sans
4550 family. The @-mark indicates the name of the property value for which a
4551 named-value can be used. The name "flowing" is chosen by the author, the
4552 values specified within a given font's data.
4554 <p>In terms of the grammar, this specification defines the following
4555 productions:
4557 <pre><dfn id=fontfeaturevaluesrule>font_feature_values_rule</dfn>
4558 : <a href="#fontfeaturevaluessym"><i>FONT_FEATURE_VALUES_SYM</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#fontfamilynamelist"><i>font_family_name_list</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
4559 '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevalueblock"><i>feature_value_block</i></a>? [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevalueblock"><i>feature_value_block</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
4560 ;
4562 <dfn id=fontfamilynamelist>font_family_name_list</dfn>
4563 : <a href="#fontfamilyname"><i>font_family_name</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ',' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#fontfamilyname"><i>font_family_name</i></a> ]*
4564 ;
4566 <dfn id=fontfamilyname>font_family_name</dfn>
4567 : <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>STRING</i></a> | [ <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> ]* ]
4568 ;
4570 <dfn id=featurevalueblock>feature_value_block</dfn>
4571 : <a href="#featuretype"><i>feature_type</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
4572 '{' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevaluedefinition"><i>feature_value_definition</i></a>? [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ';' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="#featurevaluedefinition"><i>feature_value_definition</i></a>? ]* '}' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
4573 ;
4575 <dfn id=featuretype>feature_type</dfn>:
4576 <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>ATKEYWORD</i></a>
4577 ;
4579 <dfn id=featurevaluedefinition>feature_value_definition</dfn>
4580 : <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>IDENT</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ':' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>NUMBER</i></a> [ <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>NUMBER</i></a> ]*
4581 ;
4582 </pre>
4584 <p>The following new token is introduced:
4586 <pre>@{F}{O}{N}{T}{-}{F}{E}{A}{T}{U}{R}{E}{-}{V}{A}{L}{U}{E}{S} {return <dfn id=fontfeaturevaluessym>FONT_FEATURE_VALUES_SYM</dfn>;}
4587 </pre>
4589 <p>Feature value blocks are treated <a
4590 href="http://www.w3.org/TR/CSS2/syndata.html#at-rules">similar to
4591 at-rules</a>, they consist of everything up to the next block or
4592 semi-colon, whichever comes first.
4594 <p>Font feature values rules define a set of values for a specific font
4595 feature as used for a given set of families. Effectively, they define a
4596 mapping of ⟨family, feature, ident⟩ → ⟨values⟩ where
4597 ⟨values⟩ are the indices used for specific features defined for a
4598 given font.
4600 <p>The font family list uses the same syntax as that used for the <a
4601 href="#propdef-font-family" title="font-family!!property">‘<code
4602 class=property>font-family</code>’</a> property. Within feature value
4603 blocks, the feature type is ‘<code class=css>@</code>’ followed by the
4604 name of the font-specific property value (e.g. <a
4605 href="#swash"><code>@swash</code></a>). The feature type must match, using
4606 an ASCII case-insensitive comparison, one of the <em>font specific</em>
4607 values of the ‘<a href="#propdef-font-variant-alternates"><code
4608 class=property>font-variant-alternates</code></a>’ property. The values
4609 associated with a given idenitifier are limited to integer values 0 or
4610 greater.
4612 <p>If syntax errors occur within the font family list, the entire rule must
4613 be ignored. When syntax errors occur within a feature value definition,
4614 such as invalid identifiers or values, the entire feature value definition
4615 must be omitted, similar to the way syntax errors in style declarations
4616 are handled. When the <code><feature-type></code> is invalid, the
4617 entire associated feature value block must be ignored.
4619 <pre>@font-feature-values Bongo {
4620 @swash { ornate: 1; }
4621 annotation { boxed: 4; } /* should be @annotation! */
4622 @swash { double-loops: 1; flowing: -1; } /* negative value */
4623 @ornaments ; /* incomplete definition */
4624 @styleset { double-W: 14; sharp-terminals: 16 1 } /* missing ; */
4625 <a href="http://www.angryalien.com/0504/shiningbunnies.html" style="text-decoration: none;">redrum</a> /* random editing mistake */
4626 }</pre>
4628 <p>The example above is equivalent to:
4630 <pre>@font-feature-values Bongo {
4631 @swash { ornate: 1; }
4632 @swash { double-loops: 1; }
4633 @styleset { double-W: 14; sharp-terminals: 16 1; }
4634 }</pre>
4636 <p>If multiple <a
4637 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
4638 rules are defined for a given family, the resulting values defined are the
4639 union of these rules. This allows a set of named-values to be defined for
4640 a given font family globally for a site and specific additions made
4641 per-page. If the same <feature-value-name> is defined mulitple times
4642 for a given font-variant value, the last defined value is used.
4644 <pre>
4645 site.css:
4647 @font-feature-values Mercury Serif {
4648 @styleset {
4649 stacked-g: 3; /* "two-storey" versions of g, a */
4650 stacked-a: 4;
4651 }
4652 }
4654 page.css:
4656 @font-feature-values Mercury Serif {
4657 @styleset {
4658 geometric-m: 7; /* alternate version of m */
4659 }
4660 }
4662 body {
4663 font-family: Mercury Serif, serif;
4665 /* enable both the use of stacked g and alternate m */
4666 font-variant-alternates: styleset(stacked-g, geometric-m);
4667 }</pre>
4669 <p>Only named font families are allowed for <font-family>, rules that
4670 include generic or system fonts in the list of font families are
4671 considered syntax errors and the contents of the rules are ignored.
4672 However, if a user agent defines a generic font to be a specific named
4673 font (e.g. Helvetica), the settings associated with that family name will
4674 be used.
4676 <p>For <font-variant-property-value>, only font specific property value
4677 names supported by the <a href="#propdef-font-variant"
4678 title="font-variant!!property">‘<code
4679 class=property>font-variant</code>’</a> property are recognized,
4680 definitions for other value names cause a syntax error and are ignored.
4681 Each property value that is font specific is clearly marked as such.
4682 Feature value names follow the rules of CSS user identifiers and are
4683 case-sensitive. They are unique only for a given set of font families and
4684 font-variant property value; the same identifier used with a different
4685 font-variant property value is treated as a separate and distinct value.
4687 <p>Using a commonly named value allows authors to use a single style rule
4688 to cover a set of fonts for which the underlying selector is different for
4689 each font. If either font in the example below is found, a circled number
4690 glyph will be used:
4692 <pre>@font-feature-values Taisho Gothic {
4693 @annotation { boxed: 1; circled: 4; }
4694 }
4696 @font-feature-values Otaru Kisa {
4697 @annotation { circled: 1; black-boxed: 3; }
4698 }
4700 h3.title {
4701 /* circled form defined for both fonts */
4702 font-family: Taisho Gothic, Otaru Kisa;
4703 font-variant: annotation(circled);
4704 }</pre>
4706 <p>Most font specific font-variant property values take a single value
4707 (e.g. swash). The character-variant property value allows two values and
4708 styleset allows an unlimited number. If a larger number of values are
4709 assigned to a given name, a syntax error occurs and the entire
4710 <font-feature-values-declaration> is ignored.
4712 <p>For the styleset property value, multiple values indicate the style sets
4713 to be enabled. Values between 1 and 99 enable OpenType features <span
4714 class=tag>ss01</span> through <span class=tag>ss99</span>. However, the
4715 OpenType standard only officially defines <span class=tag>ss01</span>
4716 through <span class=tag>ss20</span>. Values greater than 99 or equal to 0
4717 are ignored but do not generate a syntax error when parsed.
4719 <pre>@font-feature-values Mars Serif {
4720 @styleset {
4721 alt-g: 1; /* implies ss01 = 1 */
4722 curly-quotes: 3; /* implies ss03 = 1 */
4723 code: 4 5; /* implies ss04 = 1, ss05 = 1 */
4724 }
4726 @styleset {
4727 dumb: 125; /* >99, ignored */
4728 }
4730 @swash {
4731 swishy: 3 5; /* more than 1 value for swash, syntax error */
4732 }
4733 }
4735 p.codeblock {
4736 /* implies ss03 = 1, ss04 = 1, ss05 = 1 */
4737 font-variant-alternates: styleset(curly-quotes, code);
4738 }</pre>
4740 <p>For character-variant, a single value between 1 and 99 indicates the
4741 enabling of OpenType feature <span class=tag>cv01</span> through <span
4742 class=tag>cv99</span>. For OpenType fonts, values greater than 99 or equal
4743 to 0 are ignored but do not generate a syntax error when parsed. When two
4744 values are listed, the first value indicates the feature used and the
4745 second the value passed for that feature. When two value names imply
4746 different settings for the same underlying feature the last setting is
4747 used.
4749 <pre>@font-feature-values MM Greek {
4750 @character-variant { alpha-2: 1 2; } /* implies cv01 = 2 */
4751 @character-variant { beta-3: 2 3; } /* implies cv02 = 3 */
4752 @character-variant { epsilon: 5 3 6; } /* more than 2 values, syntax error, ignored */
4753 @character-variant { gamma: 12; } /* implies cv12 = 1 */
4754 @character-variant { zeta: 20 3; } /* implies cv20 = 3 */
4755 @character-variant { zeta-2: 20 2; } /* implies cv20 = 2 */
4756 @character-variant { silly: 105; } /* >99, ignored */
4757 @character-variant { dumb: 323 3; } /* >99, ignored */
4758 }
4760 #title {
4761 /* use the third alternate beta, first alternate gamma */
4762 font-variant-alternates: character-variant(beta-3, gamma);
4763 }
4765 p {
4766 /* zeta-2 follows zeta, implies cv20 = 2 */
4767 font-variant-alternates: character-variant(zeta, zeta-2);
4768 }
4770 .special {
4771 /* zeta follows zeta-2, implies cv20 = 3 */
4772 font-variant-alternates: character-variant(zeta-2, zeta);
4773 }</pre>
4775 <p>See the <a href="#om-fontfeaturevalues">object model reference
4776 section</a> for a description of the interfaces used to modify these rules
4777 via the CSS Object Model.
4779 <div class=figure><img alt="Matching text on Byzantine seals using
4780 character variants" src=byzantineseal.png>
4781 <p class=caption>Byzantine seal text displayed with character variants
4782 </div>
4784 <div class=example>
4785 <p>In the figure above, the text in red is rendered using a font
4786 containing character variants that mimic the character forms found on a
4787 Byzantine seal from the 8th century A.D. Two lines below is the same text
4788 displayed in a font without variants. Note the two variants for U and N
4789 used on the seal.</p>
4791 <pre>@font-feature-values Athena Ruby {
4792 @character-variant {
4793 leo-B: 2 1;
4794 leo-M: 13 3;
4795 leo-alt-N: 14 1;
4796 leo-N: 14 2;
4797 leo-T: 20 1;
4798 leo-U: 21 2;
4799 leo-alt-U: 21 4;
4800 }
4801 }
4803 p {
4804 font-variant: discretionary-ligatures,
4805 character-variant(leo-B, leo-M, leo-N, leo-T, leo-U);
4806 }
4808 span.alt-N {
4809 font-variant-alternates: character-variant(leo-alt-N);
4810 }
4812 span.alt-U {
4813 font-variant-alternates: character-variant(leo-alt-U);
4814 }
4816 <p>ENO....UP͞RSTU<span class="alt-U">U</span>͞<span class="alt-U">U</span>ΚΑΙTỤẠG̣IUPNS</p>
4818 <p>LEON|ΚΑΙCONSTA|NTI<span class="alt-N">N</span>OS..|STOIBAṢ.|LIṢROM|AIO<span class="alt-N">N</span></p>
4819 </pre>
4820 </div>
4822 <h3 id=font-variant-east-asian-prop><span class=secno>6.10 </span>East
4823 Asian text rendering: the <a
4824 href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
4825 property</h3>
4827 <table class=propdef id=namefont-variant-east-asianvaluenormal-l>
4828 <tbody>
4829 <tr>
4830 <td>Name:
4832 <td><dfn
4833 id=propdef-font-variant-east-asian>font-variant-east-asian</dfn>
4835 <tr>
4836 <td>Value:
4838 <td><a href="#font-variant-east-asian-normal-value"
4839 title="normal!!font-variant-east-asian">normal</a> | [ <a
4840 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
4841 || <a
4842 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
4843 || <a href="#ruby">ruby</a> ]
4845 <tr>
4846 <td>Initial:
4848 <td>normal
4850 <tr>
4851 <td>Applies to:
4853 <td>all elements
4855 <tr>
4856 <td>Inherited:
4858 <td>yes
4860 <tr>
4861 <td>Percentages:
4863 <td>N/A
4865 <tr>
4866 <td>Media:
4868 <td>visual
4870 <tr>
4871 <td>Computed value:
4873 <td>as specified
4875 <tr>
4876 <td>Animatable:
4878 <td>no
4879 </table>
4881 <p>Allows control of glyph substitution and sizing in East Asian text.
4883 <pre
4884 class=prod><dfn id=east-asian-variant-values><var><east-asian-variant-values></var></dfn> = [ <a href="#jis78">jis78</a> | <a href="#jis83">jis83</a> | <a href="#jis90">jis90</a> | <a href="#jis04">jis04</a> | <a href="#simplified">simplified</a> | <a href="#traditional">traditional</a> ]</pre>
4886 <pre
4887 class=prod><dfn id=east-asian-width-values><var><east-asian-width-values></var></dfn> = [ <a href="#full-width">full-width</a> | <a href="#proportional-width">proportional-width</a> ]</pre>
4889 <p>Individual values have the following meanings:
4891 <dl>
4892 <dt><dfn id=font-variant-east-asian-normal-value
4893 title="normal!!font-variant-east-asian">normal</dfn>
4895 <dd>None of the features listed below are enabled.
4897 <dt><dfn id=jis78>jis78</dfn>
4899 <dd>Enables rendering of JIS78 forms (OpenType feature: <span
4900 class=tag>jp78</span>).
4901 </dl>
4903 <div class=featex><img alt="JIS78 form example" src=jp78.png></div>
4905 <dl>
4906 <dt><dfn id=jis83>jis83</dfn>
4908 <dd>Enables rendering of JIS83 forms (OpenType feature: <span
4909 class=tag>jp83</span>).
4911 <dt><dfn id=jis90>jis90</dfn>
4913 <dd>Enables rendering of JIS90 forms (OpenType feature: <span
4914 class=tag>jp90</span>).
4916 <dt><dfn id=jis04>jis04</dfn>
4918 <dd>Enables rendering of JIS2004 forms (OpenType feature: <span
4919 class=tag>jp04</span>).
4920 <p>The various JIS variants reflect the glyph forms defined in different
4921 Japanese national standards. Fonts generally include glyphs defined by
4922 the most recent national standard but it's sometimes necessary to use
4923 older variants, to match signage for example.</p>
4925 <dt><dfn id=simplified>simplified</dfn>
4927 <dd>Enables rendering of simplified forms (OpenType feature: <span
4928 class=tag>smpl</span>).
4930 <dt><dfn id=traditional>traditional</dfn>
4932 <dd>Enables rendering of traditional forms (OpenType feature: <span
4933 class=tag>trad</span>).
4934 </dl>
4936 <p>The ‘<a href="#simplified"><code
4937 class=property>simplified</code></a>’ and ‘<a
4938 href="#traditional"><code class=property>traditional</code></a>’ values
4939 allow control over the glyph forms for characters which have been
4940 simplified over time but for which the older, traditional form is still
4941 used in some contexts. The exact set of characters and glyph forms will
4942 vary to some degree by context for which a given font was designed.
4944 <div class=featex><img alt="tradtional form example" src=trad.png></div>
4946 <dl>
4947 <dt><dfn id=full-width>full-width</dfn>
4949 <dd>Enables rendering of full-width variants (OpenType feature: <span
4950 class=tag>fwid</span>).
4952 <dt><dfn id=proportional-width>proportional-width</dfn>
4954 <dd>Enables rendering of proportionally-spaced variants (OpenType feature:
4955 <span class=tag>pwid</span>).
4956 </dl>
4958 <div class=featex><img alt="proportionally spaced Japanese example"
4959 src=pwid.png></div>
4961 <dl>
4962 <dt><dfn id=ruby>ruby</dfn>
4964 <dd>Enables display of ruby variant glyphs (OpenType feature: <span
4965 class=tag>ruby</span>). Since ruby text is generally smaller than the
4966 associated body text, font designers can design special glyphs for use
4967 with ruby that are more readable than scaled down versions of the default
4968 glyphs. Only glyph selection is affected, there is no associated font
4969 scaling or other change that affects line layout. The red ruby text below
4970 is shown with default glyphs (top) and with ruby variant glyphs (bottom).
4971 Note the slight difference in stroke thickness.
4972 </dl>
4974 <div class=featex><img alt="ruby variant example" src=rubyshinkansen.png></div>
4976 <h3 id=font-variant-prop><span class=secno>6.11 </span>Overall shorthand
4977 for font rendering: the <a href="#propdef-font-variant">font-variant</a>
4978 property</h3>
4980 <table class=propdef id=namefont-variantvaluenormal-none-ltcommo>
4981 <tbody>
4982 <tr>
4983 <td>Name:
4985 <td><dfn id=propdef-font-variant
4986 title="font-variant!!property">font-variant</dfn>
4988 <tr>
4989 <td>Value:
4991 <td><a href="#font-variant-normal-value"
4992 title="normal!!font-variant">normal</a> | <a
4993 href="#font-variant-none-value" title="none!!font-variant">none</a> | [
4994 <a href="#common-lig-values"><var><common-lig-values></var></a>
4995 || <a
4996 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
4997 || <a
4998 href="#historical-lig-values"><var><historical-lig-values></var></a>
4999 || <a
5000 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
5001 || <a href="#stylistic"><var
5002 title=stylistic>stylistic(<feature-value-name>)</var></a> || <a
5003 href="#historical-forms"><var>historical-forms</var></a> || <a
5004 href="#styleset"><var
5005 title=styleset>styleset(<feature-value-name> #)</var></a> || <a
5006 href="#character-variant"><var
5007 title=character-variant>character-variant(<feature-value-name>
5008 #)</var></a> || <a href="#swash"><var
5009 title=swash>swash(<feature-value-name>)</var></a> || <a
5010 href="#ornaments"><var
5011 title=ornaments>ornaments(<feature-value-name>)</var></a> || <a
5012 href="#annotation"><var
5013 title=annotation>annotation(<feature-value-name>)</var></a> || [
5014 <a href="#small-caps"><i>small-caps</i></a> | <a
5015 href="#all-small-caps"><i>all-small-caps</i></a> | <a
5016 href="#petite-caps"><i>petite-caps</i></a> | <a
5017 href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
5018 href="#unicase"><i>unicase</i></a> | <a
5019 href="#titling-caps"><i>titling-caps</i></a> ] || <a
5020 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
5021 || <a
5022 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
5023 || <a
5024 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
5025 || <a href="#ordinal"><i>ordinal</i></a> || <a
5026 href="#slashed-zero"><i>slashed-zero</i></a> || <a
5027 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
5028 || <a
5029 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
5030 || <a href="#ruby"><i>ruby</i></a> ]
5032 <tr>
5033 <td>Initial:
5035 <td>normal
5037 <tr>
5038 <td>Applies to:
5040 <td>all elements
5042 <tr>
5043 <td>Inherited:
5045 <td>yes
5047 <tr>
5048 <td>Percentages:
5050 <td>see individual properties
5052 <tr>
5053 <td>Media:
5055 <td>visual
5057 <tr>
5058 <td>Computed value:
5060 <td>see individual properties
5062 <tr>
5063 <td>Animatable:
5065 <td>see individual properties
5066 </table>
5068 <p>The ‘<code class=property>font-variant</code>’ property is a
5069 shorthand for all font-variant subproperties. The value <dfn
5070 id=font-variant-normal-value title="normal!!font-variant">‘<code
5071 class=property>normal</code>’</dfn> resets all subproperties of
5072 font-variant to their inital value. The <dfn id=font-variant-none-value
5073 title="none!!font-variant">‘<code class=property>none</code>’</dfn>
5074 value sets ‘<a href="#propdef-font-variant-ligatures"><code
5075 class=property>font-variant-ligatures</code></a>’ to ‘<code
5076 class=property>none</code>’ and resets all other font feature properties
5077 to their initial value. Like other shorthands, using <a
5078 href="#propdef-font-variant" title="font-variant!!property">‘<code
5079 class=property>font-variant</code>’</a> resets unspecified font-variant
5080 subproperties to their initial values. It does not reset the values of
5081 either ‘<a href="#propdef-font-language-override"><code
5082 class=property>font-language-override</code></a>’ or <a
5083 href="#propdef-font-feature-settings"
5084 title="font-feature-settings!!property">‘<code
5085 class=property>font-feature-settings</code>’</a>.
5087 <h3 id=font-feature-settings-prop><span class=secno>6.12 </span>Low-level
5088 font feature settings control: the <a
5089 href="#propdef-font-feature-settings">font-feature-settings</a> property</h3>
5091 <table class=propdef id=namefont-feature-settingsvaluenormal-ltf>
5092 <tbody>
5093 <tr>
5094 <td>Name:
5096 <td><dfn id=propdef-font-feature-settings
5097 title="font-feature-settings!!property">font-feature-settings</dfn>
5099 <tr>
5100 <td>Value:
5102 <td><a href="#font-feature-settings-normal-value"
5103 title="normal!!font-feature-settings">normal</a> | <a
5104 href="#feature-tag-value"><var><feature-tag-value></var></a> #
5106 <tr>
5107 <td>Initial:
5109 <td>normal
5111 <tr>
5112 <td>Applies to:
5114 <td>all elements
5116 <tr>
5117 <td>Inherited:
5119 <td>yes
5121 <tr>
5122 <td>Percentages:
5124 <td>N/A
5126 <tr>
5127 <td>Media:
5129 <td>visual
5131 <tr>
5132 <td>Computed value:
5134 <td>as specified
5136 <tr>
5137 <td>Animatable:
5139 <td>no
5140 </table>
5142 <p>This property provides low-level control over OpenType font features. It
5143 is intended as a way of providing access to font features that are not
5144 widely used but are needed for a particular use case.
5146 <p>Authors should generally use <a href="#propdef-font-variant"
5147 title="font-variant!!property">‘<code
5148 class=property>font-variant</code>’</a> and its related subproperties
5149 whenever possible and only use this property for special cases where its
5150 use is the only way of accessing a particular infrequently used font
5151 feature.
5153 <pre>/* enable small caps and use second swash alternate */
5154 font-feature-settings: "smcp", "swsh" 2;</pre>
5156 <p>A value of <dfn id=font-feature-settings-normal-value
5157 title="normal!!font-feature-settings">‘<code
5158 class=property>normal</code>’</dfn> means that no change in glyph
5159 selection or positioning occurs due to this property.
5161 <p>Feature tag values have the following syntax:
5163 <pre
5164 class=prod><dfn id=feature-tag-value><var><feature-tag-value></var></dfn> = <string> [ <integer> | on | off ]?</pre>
5166 <p>The <string> is a case-sensitive OpenType feature tag. As
5167 specified in the OpenType specification, feature tags contain four ASCII
5168 characters. Tag strings longer or shorter than four characters, or
5169 containing characters outside the U+20–7E codepoint range are invalid.
5170 Feature tags need only match a feature tag defined in the font, so they
5171 are not limited to explicitly registered OpenType features. Fonts defining
5172 custom feature tags should follow the <a
5173 href="http://www.microsoft.com/typography/otspec/featuretags.htm">tag name
5174 rules</a> defined in the OpenType specification <a
5175 href="#OPENTYPE-FEATURES"
5176 rel=biblioentry>[OPENTYPE-FEATURES]<!--{{!OPENTYPE-FEATURES}}--></a>.
5177 Feature tags not present in the font are ignored; a user agent must not
5178 attempt to synthesize fallback behavior based on these feature tags.
5180 <p>This means that explicitly disabling the <span class=tag>kern</span>
5181 feature will not affect the application of kerning data found in the
5182 ‘<code class=property>kern</code>’ table (as opposed to kerning data
5183 associated with the <span class=tag>kern</span> feature in the ‘<code
5184 class=property>GPOS</code>’ table). Authors should use the ‘<a
5185 href="#propdef-font-kerning"><code
5186 class=property>font-kerning</code></a>’ property to explictly enable or
5187 disable kerning since this property affects both types of kerning.
5189 <p>If present, a value indicates an index used for glyph selection. An
5190 <integer> value must be 0 or greater. A value of 0 indicates that
5191 the feature is disabled. For boolean features, a value of 1 enables the
5192 feature. For non-boolean features, a value of 1 or greater enables the
5193 feature and indicates the feature selection index. A value of ‘<code
5194 class=property>on</code>’ is synonymous with 1 and ‘<code
5195 class=property>off</code>’ is synonymous with 0. If the value is
5196 omitted, a value of 1 is assumed.
5198 <pre>
5199 font-feature-settings: "dlig" 1; /* dlig=1 enable discretionary ligatures */
5200 font-feature-settings: "smcp" on; /* smcp=1 enable small caps */
5201 font-feature-settings: 'c2sc'; /* c2sc=1 enable caps to small caps */
5202 font-feature-settings: "liga" off; /* liga=0 no common ligatures */
5203 font-feature-settings: "tnum", 'hist'; /* tnum=1, hist=1 enable tabular numbers and historical forms */
5204 font-feature-settings: "tnum" "hist"; /* invalid, need a comma-delimited list */
5205 font-feature-settings: "palin" off; /* good idea but invalid tagname */
5206 font-feature-settings: "PKRN"; /* PKRN=1 enable custom feature */
5207 font-feature-settings: dlig; /* invalid, tag must be a string */
5208 </pre>
5210 <p>When values greater than the range supported by the font are specified,
5211 the behavior is explicitly undefined. For boolean features, in general
5212 these will enable the feature. For non-boolean features, out of range
5213 values will in general be equivalent to a 0 value. However, in both cases
5214 the exact behavior will depend upon the way the font is designed
5215 (specifically, which type of lookup is used to define the feature).
5217 <p>Although specifically defined for OpenType feature tags, feature tags
5218 for other modern font formats that support font features may be added in
5219 the future. Where possible, features defined for other font formats should
5220 attempt to follow the pattern of registered OpenType tags.
5222 <div class=example>
5223 <p>The Japanese text below will be rendered with half-width kana
5224 characters:</p>
5226 <pre lang=ja>
5227 body { font-feature-settings: "hwid"; /* Half-width OpenType feature */ }
5229 <p>毎日<a href="http://images.google.com/images?q=%E3%82%AB%E3%83%AC%E3%83%BC" style="text-decoration: none;">カレー</a>食べてるのに、飽きない</p>
5230 </pre>
5231 </div>
5233 <h3 id=font-language-override-prop><span class=secno>6.13 </span>Font
5234 language override: the <a
5235 href="#propdef-font-language-override">font-language-override</a> property</h3>
5237 <table class=propdef id=namefont-language-overridevaluenormal-lt>
5238 <tbody>
5239 <tr>
5240 <td>Name:
5242 <td><dfn id=propdef-font-language-override>font-language-override</dfn>
5244 <tr>
5245 <td>Value:
5247 <td><a href="#font-language-override-normal-value"
5248 title="normal!!font-language-override">normal</a> | <a
5249 href="#font-language-override-string-value"><var><string></var></a>
5251 <tr>
5252 <td>Initial:
5254 <td><a href="#font-language-override-normal-value"
5255 title="normal!!font-language-override">normal</a>
5257 <tr>
5258 <td>Applies to:
5260 <td>all elements
5262 <tr>
5263 <td>Inherited:
5265 <td>yes
5267 <tr>
5268 <td>Percentages:
5270 <td>N/A
5272 <tr>
5273 <td>Media:
5275 <td>visual
5277 <tr>
5278 <td>Computed value:
5280 <td>as specified
5282 <tr>
5283 <td>Animatable:
5285 <td>no
5286 </table>
5288 <p>Normally, authors can control the use of language-specific glyph
5289 substitutions and positioning by setting the content language of an
5290 element, as <a href="#language-specific-support">described above</a>:
5292 <pre><!-- Display text using S'gaw Karen specific features -->
5293 <p lang="ksw">...</p></pre>
5295 <p>In some cases, authors may need to specify a language system that
5296 differs from the content language, for example due to the need to mimic
5297 another language's typographic traditions. The ‘<a
5298 href="#propdef-font-language-override"><code
5299 class=property>font-language-override</code></a>’ property allows
5300 authors to explicitly specify the language system of the font, overriding
5301 the language system implied by the content language.
5303 <p>Values have the following meanings:
5305 <dl>
5306 <dt><dfn id=font-language-override-normal-value
5307 title="normal!!font-language-override">normal</dfn>
5309 <dd>specifies that when rendering with OpenType fonts, the content
5310 language of the element is used to infer the OpenType language system
5312 <dt><dfn
5313 id=font-language-override-string-value><var><string></var></dfn>
5315 <dd>single three-letter OpenType <a
5316 href="http://www.microsoft.com/typography/otspec/languagetags.htm">language
5317 system tag</a>, specifies the OpenType language system to be used instead
5318 of the language system implied by the language of the element
5319 </dl>
5321 <p>Use of invalid OpenType language system tags must not generate a parse
5322 error but must be ignored when doing glyph selection and placement.
5324 <div class=example>
5325 <p>The <a href="http://www.un.org/en/documents/udhr/index.shtml">Universal
5326 Declaration of Human Rights</a> has been translated into a wide variety
5327 of languages. In Turkish, Article 9 of this document might be marked up
5328 as below:</p>
5330 <pre lang=tr><body lang="tr">
5332 <h4>Madde 9</h4>
5333 <p>Hiç kimse keyfi olarak tutuklanamaz, alıkonulanamaz veya sürülemez.</p>
5334 </pre>
5336 <p>Here the user agent uses the value of the ‘<code
5337 class=property>lang</code>’ attribute when rendering text and
5338 appropriately renders this text without ‘<code
5339 class=property>fi</code>’ ligatures. There is no need to use the ‘<a
5340 href="#propdef-font-language-override"><code
5341 class=property>font-language-override</code></a>’ property.</p>
5343 <p>However, a given font may lack support for a specific language. In this
5344 situation authors may need to use the typographic conventions of a
5345 related language that are supported by that font:</p>
5347 <pre lang=mk><body lang="mk"> <!-- Macedonian lang code -->
5349 body { font-language-override: "SRB"; /* Serbian OpenType language tag */ }
5351 <h4>Члeн 9</h4>
5352 <p>Никoj чoвeк нeмa дa бидe пoдлoжeн нa прoизвoлнo aпсeњe, притвoр или прoгoнувaњe.</p>
5354 </pre>
5356 <p>The Macedonian text here will be rendered using Serbian typographic
5357 conventions, with the assumption that the font specified supports
5358 Serbian.</p>
5359 </div>
5361 <p><a id=rendering-considerations></a>
5363 <h2 id=font-feature-resolution><span class=secno>7 </span>Font Feature
5364 Resolution</h2>
5366 <p>As described in the previous section, font features can be enabled in a
5367 variety of ways, either via the use of <a href="#propdef-font-variant"
5368 title="font-variant!!property">‘<code
5369 class=property>font-variant</code>’</a> or <a
5370 href="#propdef-font-feature-settings"
5371 title="font-feature-settings!!property">‘<code
5372 class=property>font-feature-settings</code>’</a> in a style rule or
5373 within an <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
5374 The resolution order for the union of these settings is defined below.
5375 Features defined via CSS properties are applied on top of layout engine
5376 default features.
5378 <h3 id=default-features><span class=secno>7.1 </span>Default features</h3>
5380 <p>For OpenType fonts, user agents must enable the default features defined
5381 in the OpenType documentation for a given script and writing mode.
5382 Required ligatures, common ligatures and contextual forms must be enabled
5383 by default (OpenType features: <span class=tag>rlig, liga, clig,
5384 calt</span>), along with localized forms (OpenType feature: <span
5385 class=tag>locl</span>), and features required for proper display of
5386 composed characters and marks (OpenType features: <span class=tag>ccmp,
5387 mark, mkmk</span>). These features must always be enabled, even when the
5388 value of the <a href="#propdef-font-variant"
5389 title="font-variant!!property">‘<code
5390 class=property>font-variant</code>’</a> and <a
5391 href="#propdef-font-feature-settings"
5392 title="font-feature-settings!!property">‘<code
5393 class=property>font-feature-settings</code>’</a> properties is ‘<a
5394 href="#normal"><code class=property>normal</code></a>’. Individual
5395 features are only disabled when explicitly overridden by the author, as
5396 when ‘<a href="#propdef-font-variant-ligatures"><code
5397 class=property>font-variant-ligatures</code></a>’ is set to ‘<a
5398 href="#no-common-ligatures"><code
5399 class=property>no-common-ligatures</code></a>’. For handling complex
5400 scripts such as <a
5401 href="http://www.microsoft.com/typography/otfntdev/arabicot/features.aspx">Arabic</a>,
5402 <a
5403 href="http://www.microsoft.com/typography/otfntdev/mongolot/features.htm">Mongolian</a>
5404 or <a
5405 href="http://www.microsoft.com/typography/otfntdev/devanot/features.aspx">Devanagari</a>
5406 additional features are required. For upright text within vertical text
5407 runs, vertical alternates (OpenType feature: <span class=tag>vert</span>)
5408 must be enabled.
5410 <h3 id=feature-precedence><span class=secno>7.2 </span>Feature precedence</h3>
5412 <p>General and font specific font feature property settings are resolved in
5413 the order below, in ascending precedence order. This ordering is used to
5414 construct a combined list of font features that affect a given text run.
5416 <ol>
5417 <li>Font features enabled by default, including features required for a
5418 given script.
5420 <li>If the font is defined via an <a
5421 href="#at-font-face-rule"><code>@font-face</code></a> rule, the font
5422 features implied by the font-variant descriptor in the <a
5423 href="#at-font-face-rule"><code>@font-face</code></a> rule.
5425 <li>If the font is defined via an <a
5426 href="#at-font-face-rule"><code>@font-face</code></a> rule, the font
5427 features implied by the font-feature-settings descriptor in the <a
5428 href="#at-font-face-rule"><code>@font-face</code></a> rule.
5430 <li>Feature settings determined by properties other than <a
5431 href="#propdef-font-variant" title="font-variant!!property">‘<code
5432 class=property>font-variant</code>’</a> or <a
5433 href="#propdef-font-feature-settings"
5434 title="font-feature-settings!!property">‘<code
5435 class=property>font-feature-settings</code>’</a>. For example, setting
5436 a non-default value for the ‘<code
5437 class=property>letter-spacing</code>’ property disables ligatures.
5439 <li>Font features implied by the value of the <a
5440 href="#propdef-font-variant" title="font-variant!!property">‘<code
5441 class=property>font-variant</code>’</a> property, the related
5442 font-variant subproperties and any other CSS property that may use
5443 OpenType features (e.g. the ‘<a href="#propdef-font-kerning"><code
5444 class=property>font-kerning</code></a>’ property).
5446 <li>Font features implied by the value of <a
5447 href="#propdef-font-feature-settings"
5448 title="font-feature-settings!!property">‘<code
5449 class=property>font-feature-settings</code>’</a> property.
5450 </ol>
5452 <p>This ordering allows authors to set up a general set of defaults for
5453 fonts within their <a
5454 href="#at-font-face-rule"><code>@font-face</code></a> rules, then override
5455 them with property settings for specific elements. General property
5456 settings override the settings in <a
5457 href="#at-font-face-rule"><code>@font-face</code></a> rules and low-level
5458 font feature settings override <a href="#propdef-font-variant"
5459 title="font-variant!!property">‘<code
5460 class=property>font-variant</code>’</a> property settings.
5462 <p>For situations where the combined list of font feature settings contains
5463 more than one value for the same feature, the last value is used. When a
5464 font lacks support for a given underlying font feature, text is simply
5465 rendered as if that font feature was not enabled; font fallback does not
5466 occur and no attempt is made to synthesize the feature except where
5467 explicitly noted for specific properties.
5469 <h3 id=feature-precedence-examples><span class=secno>7.3 </span>Feature
5470 precedence examples</h3>
5472 <div class=example>
5473 <p>With the styles below, numbers are rendered proportionally when used
5474 within a paragraph but are shown in tabular form within tables of prices:</p>
5476 <pre>body {
5477 font-variant-numeric: proportional-nums;
5478 }
5480 table.prices td {
5481 font-variant-numeric: tabular-nums;
5482 }
5483 </pre>
5484 </div>
5486 <div class=example>
5487 <p>When the font-variant descriptor is used within an <a
5488 href="#at-font-face-rule"><code>@font-face</code></a> rule, it only
5489 applies to the font defined by that rule.</p>
5491 <pre>@font-face {
5492 font-family: MainText;
5493 src: url(http://example.com/font.ttf);
5494 font-variant: oldstyle-nums proportional-nums styleset(1,3);
5495 }
5497 body {
5498 font-family: MainText, Helvetica;
5499 }
5501 table.prices td {
5502 font-variant-numeric: tabular-nums;
5503 }
5504 </pre>
5506 <p>In this case, old-style numerals will be used throughout but only where
5507 the font "MainText" is used. Just as in the previous example, tabular
5508 values will be used in price tables since ‘<a
5509 href="#tabular-nums"><code class=property>tabular-nums</code></a>’
5510 appears in a general style rule and its use is mutually exclusive with
5511 ‘<a href="#proportional-nums"><code
5512 class=property>proportional-nums</code></a>’. Stylistic alternate sets
5513 will only be used where MainText is used.</p>
5514 </div>
5516 <div class=example>
5517 <p>The <a href="#at-font-face-rule"><code>@font-face</code></a> rule can
5518 also be used to access font features in locally available fonts via the
5519 use of <code>local()</code> in the ‘<a href="#descdef-src"><code
5520 class=property>src</code></a>’ descriptor of the <a
5521 href="#at-font-face-rule"><code>@font-face</code></a> definition:</p>
5523 <pre>@font-face {
5524 font-family: BodyText;
5525 src: local("HiraMaruPro-W4");
5526 font-variant: proportional-width;
5527 font-feature-settings: "ital"; /* Latin italics within CJK text feature */
5528 }
5530 body { font-family: BodyText, serif; }
5531 </pre>
5533 <p>If available, a Japanese font "Hiragino Maru Gothic" will be used. When
5534 text rendering occurs, Japanese kana will be proportionally spaced and
5535 Latin text will be italicised. Text rendered with the fallback serif font
5536 will use default rendering properties.</p>
5537 </div>
5539 <div class=example>
5540 <p>In the example below, discretionary ligatures are enabled only for a
5541 downloadable font but are disabled within spans of class "special":</p>
5543 <pre>@font-face {
5544 font-family: main;
5545 src: url(fonts/ffmeta.woff) format("woff");
5546 font-variant: discretionary-ligatures;
5547 }
5549 body { font-family: main, Helvetica; }
5550 span.special { font-variant-ligatures: no-discretionary-ligatures; }
5551 </pre>
5553 <p>Adding an discretionary style rule with the <a
5554 href="#at-font-face-rule"><code>@font-face</code></a> above:</p>
5556 <pre>body { font-family: main, Helvetica; }
5557 span { font-feature-settings: "dlig"; }
5558 span.special { font-variant-ligatures: no-discretionary-ligatures; }
5559 </pre>
5561 <p>Within spans of class "special", discretionary ligatures <em>will</em>
5562 be rendered. This is because both the <a
5563 href="#propdef-font-feature-settings"
5564 title="font-feature-settings!!property">‘<code
5565 class=property>font-feature-settings</code>’</a> and ‘<a
5566 href="#propdef-font-variant-ligatures"><code
5567 class=property>font-variant-ligatures</code></a>’ properties apply to
5568 these spans. Although the ‘<code class=css>no-discretionary
5569 ligatures</code>’ setting of ‘<a
5570 href="#propdef-font-variant-ligatures"><code
5571 class=property>font-variant-ligatures</code></a>’ effectively disables
5572 the OpenType <span class=tag>dlig</span> feature, because the <a
5573 href="#propdef-font-feature-settings"
5574 title="font-feature-settings!!property">‘<code
5575 class=property>font-feature-settings</code>’</a> is resolved after
5576 that, the ‘<code class=property>dlig</code>’ value reenables
5577 discretionary ligatures.</p>
5578 </div>
5580 <h2 id=object-model><span class=secno>8 </span>Object Model</h2>
5582 <p>The contents of <a href="#at-font-face-rule"><code>@font-face</code></a>
5583 and <a
5584 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
5585 rules can be accessed via the following extensions to the CSS Object
5586 Model.
5588 <h3 id=om-fontface><span class=secno>8.1 </span>The <a
5589 href="#cssfontfacerule"><code>CSSFontFaceRule</code></a> interface</h3>
5591 <p>The <dfn id=cssfontfacerule>CSSFontFaceRule</dfn> interface represents a
5592 <a href="#at-font-face-rule"><code>@font-face</code></a> rule.
5594 <pre class=idl>
5595 interface CSSFontFaceRule : CSSRule {
5596 attribute DOMString family;
5597 attribute DOMString src;
5598 attribute DOMString style;
5599 attribute DOMString weight;
5600 attribute DOMString stretch;
5601 attribute DOMString unicodeRange;
5602 attribute DOMString variant;
5603 attribute DOMString featureSettings;
5604 }</pre>
5606 <p>The DOM Level 2 Style specification <a href="#DOM-LEVEL-2-STYLE"
5607 rel=biblioentry>[DOM-LEVEL-2-STYLE]<!--{{DOM-LEVEL-2-STYLE}}--></a>
5608 defined a different variant of this rule. This definition supercedes that
5609 one.
5611 <h3 id=om-fontfeaturevalues><span class=secno>8.2 </span>The <a
5612 href="#cssfontfeaturevaluesrule"><code>CSSFontFeatureValuesRule</code></a>
5613 interface</h3>
5615 <p>The <code>CSSRule</code> interface is extended as follows:
5617 <pre class=idl>partial interface CSSRule {
5618 const unsigned short FONT_FEATURE_VALUES_RULE = 14;
5619 }</pre>
5621 <p>The <dfn id=cssfontfeaturevaluesrule>CSSFontFeatureValuesRule</dfn>
5622 interface represents a <a
5623 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
5624 rule.
5626 <pre class=idl>interface CSSFontFeatureValuesRule : CSSRule {
5627 readonly attribute DOMString familyList;
5628 readonly attribute DOMString valueText;
5629 };</pre>
5631 <dl class=idl-attributes>
5632 <dt><var>familyList</var> of type <code>DOMString</code>, readonly
5634 <dd>The list of one or more font families for which a given set of feature
5635 values is defined.
5637 <dt><var>valueText</var> of type <code>DOMString</code>, readonly
5639 <dd>Serialized set of feature values.
5640 </dl>
5642 <p class=issue>Should this be extended to make <a
5643 href="#cssfontfeaturevaluesrule"><code>CSSFontFeatureValuesRule</code></a>
5644 be a subclass of <code>CSSGroupingRule</code> with other CSSRule
5645 subclasses for each value definition block?
5647 <h2 class=no-num id=platform-props-to-css>Appendix A: Mapping platform font
5648 properties to CSS properties</h2>
5650 <p><em>This appendix is included as background for some of the problems and
5651 situations that are described in other sections. It should be viewed as
5652 informative only.</em>
5654 <p>Font properties in CSS are designed to be independent of the underlying
5655 font formats used; they can be used to specify bitmap fonts, Type1 fonts,
5656 SVG fonts in addition to the common TrueType and OpenType fonts. But there
5657 are facets of the TrueType and OpenType formats that often cause confusion
5658 for authors and present challenges to implementers on different platforms.
5660 <p>Originally developed at Apple, TrueType was designed as an outline font
5661 format for both screen and print. Microsoft joined Apple in developing the
5662 TrueType format and both platforms have supported TrueType fonts since
5663 then. Font data in the TrueType format consists of a set of tables
5664 distinguished with common four-letter tag names, each containing a
5665 specific type of data. For example, naming information, including
5666 copyright and license information, is stored in the ‘<code
5667 class=property>name</code>’ table. The <a
5668 href="#character-map"><em>character map</em></a> (‘<code
5669 class=property>cmap</code>’) table contains a mapping of character
5670 encodings to glyphs. Apple later added additional tables for supporting
5671 enhanced typographic functionality; these are now called Apple Advanced
5672 Typography, or AAT, fonts. Microsoft and Adobe developed a separate set of
5673 tables for advanced typography and called their format OpenType <a
5674 href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>.
5676 <p>In many cases the font data used under Microsoft Windows or Linux is
5677 slightly different from the data used under Apple's Mac OS X because the
5678 TrueType format allowed for explicit variation across platforms. This
5679 includes font metrics, names and <a href="#character-map"><em>character
5680 map</em></a> data.
5682 <p>Specifically, font family name data is handled differently across
5683 platforms. For TrueType and OpenType fonts these names are contained in
5684 the ‘<code class=property>name</code>’ table, in name records with
5685 name ID 1. Mulitple names can be stored for different locales, but
5686 Microsoft recommends fonts always include at least a US English version of
5687 the name. On Windows, Microsoft made the decision for backwards
5688 compatibility to limit this family name to a maximum of four faces; for
5689 larger groupings the "preferred family" (name ID 16) or "WWS family" (name
5690 ID 21) can be used. Other platforms such as OSX don't have this
5691 limitation, so the family name is used to define all possible groupings.
5693 <p>Other name table data provides names used to uniquely identify a
5694 specific face within a family. The full font name (name ID 4) and the
5695 Postscript name (name ID 6) describe a single face uniquely. For example,
5696 the bold face of the Gill Sans family has a fullname of "Gill Sans Bold"
5697 and a Postscript name of "GillSans-Bold". There can be multiple localized
5698 versions of the fullname for a given face, but the Postscript name is
5699 always a unique name made from a limited set of ASCII characters.
5701 <p>On various platforms, different names are used to search for a font. For
5702 example, with the Windows GDI CreateIndirectFont API, either a family or
5703 fullname can be used to lookup a face, while on Mac OS X the
5704 CTFontCreateWithName API call is used to lookup a given face using the
5705 fullname and Postscript name. Under Linux, the fontconfig API allows fonts
5706 to be searched using any of these names. In situations where platform
5707 API's automatically substitute other font choices, it may be necessary to
5708 verify a returned font matches a given name.
5710 <p>The weight of a given face can be determined via the usWeightClass field
5711 of the OS/2 table or inferred from the style name (name ID 2). Likewise,
5712 the width can be determined via the usWidthClass of the OS/2 table or
5713 inferred from the style name. For historical reasons related to synthetic
5714 bolding at weights 200 or lower with the Windows GDI API, font designers
5715 have sometimes skewed values in the OS/2 table to avoid these weights.
5717 <p>Rendering complex scripts that use contextual shaping such as Thai,
5718 Arabic and Devanagari requires features present only in OpenType or AAT
5719 fonts. Currently, complex script rendering is supported on Windows and
5720 Linux using OpenType font features while both OpenType and AAT font
5721 features are used under Mac OS X.
5723 <h2 class=no-num id=ch-ch-ch-changes>Changes</h2>
5725 <h3 class=no-num id=recent-changes> Changes from the <a
5726 href="http://www.w3.org/TR/2013/WD-css3-fonts-20130212/">February 2013
5727 CSS3 Fonts Working Draft</a></h3>
5729 <p>Major changes include:
5731 <ul>
5732 <li>Moved font load events into a separate <a
5733 href="http://dev.w3.org/csswg/css3-font-load-events/">spec</a>
5735 <li>Tightened error handling rules for <a
5736 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
5737 rules
5739 <li>Added grammar productions for <a
5740 href="#at-font-face-rule"><code>@font-face</code></a> and <a
5741 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
5742 rules
5744 <li>Tightened definition of synthetic oblique
5746 <li>Revised definition of ‘<a href="#descdef-unicode-range"><code
5747 class=property>unicode-range</code></a>’ descriptor
5748 </ul>
5750 <h2 class=no-num id=acknowledgments>Acknowledgments</h2>
5752 <p>I'd like to thank Tal Leming, Jonathan Kew and Christopher Slye for all
5753 their help and feedback. John Hudson was kind enough to take the time to
5754 explain the subtleties of OpenType language tags and provided the example
5755 of character variant usage for displaying text on Byzantine seals. Ken
5756 Lunde and Eric Muller provided valuable feedback on CJK OpenType features
5757 and Unicode variation selectors. The idea for supporting font features by
5758 using font-variant subproperties originated with Håkon Wium Lie, Adam
5759 Twardoch and Tal Leming. Elika Etemad supplied some of the initial design
5760 ideas for the <a
5761 href="#at-font-feature-values-rule"><code>@font-feature-values</code></a>
5762 rule. Thanks also to House Industries for allowing the use of Ed Interlock
5763 in the discretionary ligatures example.
5765 <p>A special thanks to Robert Bringhurst for the sublime mind expansion
5766 that is <em>The Elements of Typographic Style</em>.
5768 <h2 class=no-num id=conformance> Conformance</h2>
5770 <h3 class=no-num id=conventions> Document Conventions</h3>
5772 <p>Conformance requirements are expressed with a combination of descriptive
5773 assertions and RFC 2119 terminology. The key words “MUST”, “MUST
5774 NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”,
5775 “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the
5776 normative parts of this document are to be interpreted as described in RFC
5777 2119. However, for readability, these words do not appear in all uppercase
5778 letters in this specification.
5780 <p>All of the text of this specification is normative except sections
5781 explicitly marked as non-normative, examples, and notes. <a
5782 href="#RFC2119" rel=biblioentry>[RFC2119]<!--{{!RFC2119}}--></a>
5784 <p>Examples in this specification are introduced with the words “for
5785 example” or are set apart from the normative text with
5786 <code>class="example"</code>, like this:
5788 <div class=example>
5789 <p>This is an example of an informative example.
5790 </div>
5792 <p>Informative notes begin with the word “Note” and are set apart from
5793 the normative text with <code>class="note"</code>, like this:
5795 <p class=note>Note, this is an informative note.
5797 <h3 class=no-num id=conformance-classes> Conformance Classes</h3>
5799 <p>Conformance to CSS Fonts Level 3 Module is defined for three conformance
5800 classes:
5802 <dl>
5803 <dt><dfn id=style-sheet title="style sheet!!as conformance class">style
5804 sheet</dfn>
5806 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
5807 style sheet</a>.
5809 <dt><dfn id=renderer>renderer</dfn>
5811 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
5812 that interprets the semantics of a style sheet and renders documents that
5813 use them.
5815 <dt><dfn id=authoring-tool>authoring tool</dfn>
5817 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
5818 that writes a style sheet.
5819 </dl>
5821 <p>A style sheet is conformant to CSS Fonts Level 3 Module if all of its
5822 declarations that use properties defined in this module have values that
5823 are valid according to the generic CSS grammar and the individual grammars
5824 of each property as given in this module.
5826 <p>A renderer is conformant to CSS Fonts Level 3 Module if, in addition to
5827 interpreting the style sheet as defined by the appropriate specifications,
5828 it supports all the features defined by CSS Fonts Level 3 Module by
5829 parsing them correctly and rendering the document accordingly. However,
5830 the inability of a UA to correctly render a document due to limitations of
5831 the device does not make the UA non-conformant. (For example, a UA is not
5832 required to render color on a monochrome monitor.)
5834 <p>An authoring tool is conformant to CSS Fonts Level 3 Module if it writes
5835 style sheets that are syntactically correct according to the generic CSS
5836 grammar and the individual grammars of each feature in this module, and
5837 meet all other conformance requirements of style sheets as described in
5838 this module.
5840 <h3 class=no-num id=partial> Partial Implementations</h3>
5842 <p>So that authors can exploit the forward-compatible parsing rules to
5843 assign fallback values, CSS renderers <strong>must</strong> treat as
5844 invalid (and <a
5845 href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore as
5846 appropriate</a>) any at-rules, properties, property values, keywords, and
5847 other syntactic constructs for which they have no usable level of support.
5848 In particular, user agents <strong>must not</strong> selectively ignore
5849 unsupported component values and honor supported values in a single
5850 multi-value property declaration: if any value is considered invalid (as
5851 unsupported values must be), CSS requires that the entire declaration be
5852 ignored.
5854 <h3 class=no-num id=experimental> Experimental Implementations</h3>
5856 <p>To avoid clashes with future CSS features, the CSS2.1 specification
5857 reserves a <a
5858 href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
5859 syntax</a> for proprietary and experimental extensions to CSS.
5861 <p>Prior to a specification reaching the Candidate Recommendation stage in
5862 the W3C process, all implementations of a CSS feature are considered
5863 experimental. The CSS Working Group recommends that implementations use a
5864 vendor-prefixed syntax for such features, including those in W3C Working
5865 Drafts. This avoids incompatibilities with future changes in the draft.
5867 <h3 class=no-num id=testing> Non-Experimental Implementations</h3>
5869 <p>Once a specification reaches the Candidate Recommendation stage,
5870 non-experimental implementations are possible, and implementors should
5871 release an unprefixed implementation of any CR-level feature they can
5872 demonstrate to be correctly implemented according to spec.
5874 <p>To establish and maintain the interoperability of CSS across
5875 implementations, the CSS Working Group requests that non-experimental CSS
5876 renderers submit an implementation report (and, if necessary, the
5877 testcases used for that implementation report) to the W3C before releasing
5878 an unprefixed implementation of any CSS features. Testcases submitted to
5879 W3C are subject to review and correction by the CSS Working Group.
5881 <p>Further information on submitting testcases and implementation reports
5882 can be found from on the CSS Working Group's website at <a
5883 href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
5884 Questions should be directed to the <a
5885 href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
5886 mailing list.
5888 <h2 class=no-num id=references>References</h2>
5890 <h3 class=no-num id=normative-references>Normative References</h3>
5891 <!--begin-normative-->
5892 <!-- Sorted by label -->
5894 <dl class=bibliography>
5895 <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
5896 <!---->
5898 <dt id=CHARMOD>[CHARMOD]
5900 <dd>Martin J. Dürst; et al. <a
5901 href="http://www.w3.org/TR/2005/REC-charmod-20050215/"><cite>Character
5902 Model for the World Wide Web 1.0: Fundamentals.</cite></a> 15 February
5903 2005. W3C Recommendation. URL: <a
5904 href="http://www.w3.org/TR/2005/REC-charmod-20050215/">http://www.w3.org/TR/2005/REC-charmod-20050215/</a>
5905 </dd>
5906 <!---->
5908 <dt id=CORS>[CORS]
5910 <dd>Anne van Kesteren. <a
5911 href="http://www.w3.org/TR/2013/CR-cors-20130129/"><cite>Cross-Origin
5912 Resource Sharing.</cite></a> 29 January 2013. W3C Candidate
5913 Recommendation. (Work in progress.) URL: <a
5914 href="http://www.w3.org/TR/2013/CR-cors-20130129/">http://www.w3.org/TR/2013/CR-cors-20130129/</a>
5915 </dd>
5916 <!---->
5918 <dt id=CSS21>[CSS21]
5920 <dd>Bert Bos; et al. <a
5921 href="http://www.w3.org/TR/2011/REC-CSS2-20110607"><cite>Cascading Style
5922 Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 7 June
5923 2011. W3C Recommendation. URL: <a
5924 href="http://www.w3.org/TR/2011/REC-CSS2-20110607">http://www.w3.org/TR/2011/REC-CSS2-20110607</a>
5925 </dd>
5926 <!---->
5928 <dt id=CSS3VAL>[CSS3VAL]
5930 <dd>Håkon Wium Lie; Tab Atkins; Elika J. Etemad. <a
5931 href="http://www.w3.org/TR/2012/CR-css3-values-20120828/"><cite>CSS
5932 Values and Units Module Level 3.</cite></a> 28 August 2012. W3C Candidate
5933 Recommendation. (Work in progress.) URL: <a
5934 href="http://www.w3.org/TR/2012/CR-css3-values-20120828/">http://www.w3.org/TR/2012/CR-css3-values-20120828/</a>
5935 </dd>
5936 <!---->
5938 <dt id=HTML5>[HTML5]
5940 <dd>Ian Hickson. <a
5941 href="http://www.w3.org/TR/2012/CR-html5-20121217/"><cite>HTML5.</cite></a>
5942 17 December 2012. W3C Candidate Recommendation. (Work in progress.) URL:
5943 <a
5944 href="http://www.w3.org/TR/2012/CR-html5-20121217/">http://www.w3.org/TR/2012/CR-html5-20121217/</a>
5945 </dd>
5946 <!---->
5948 <dt id=OPEN-FONT-FORMAT>[OPEN-FONT-FORMAT]
5950 <dd><a
5951 href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip"><cite>Information
5952 technology — Coding of audio-visual objects — Part 22: Open Font
5953 Format.</cite></a> International Organization for Standardization.
5954 ISO/IEC 14496-22:2009. URL: <a
5955 href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip">http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip</a>
5956 </dd>
5957 <!---->
5959 <dt id=OPENTYPE>[OPENTYPE]
5961 <dd><a
5962 href="http://www.microsoft.com/typography/otspec/default.htm"><cite>OpenType
5963 specification.</cite></a> Microsoft. URL: <a
5964 href="http://www.microsoft.com/typography/otspec/default.htm">http://www.microsoft.com/typography/otspec/default.htm</a>
5965 </dd>
5966 <!---->
5968 <dt id=OPENTYPE-FEATURES>[OPENTYPE-FEATURES]
5970 <dd><a
5971 href="http://www.microsoft.com/typography/otspec/featurelist.htm"><cite>OpenType
5972 feature registry.</cite></a> Microsoft. URL: <a
5973 href="http://www.microsoft.com/typography/otspec/featurelist.htm">http://www.microsoft.com/typography/otspec/featurelist.htm</a>
5974 </dd>
5975 <!---->
5977 <dt id=RFC2119>[RFC2119]
5979 <dd>S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key
5980 words for use in RFCs to Indicate Requirement Levels.</cite></a> Internet
5981 RFC 2119. URL: <a
5982 href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
5983 </dd>
5984 <!---->
5986 <dt id=UAX15>[UAX15]
5988 <dd>Mark Davis; Ken Whistler. <a
5989 href="http://www.unicode.org/reports/tr15/"><cite>Unicode Normalization
5990 Forms.</cite></a> 31 August 2012. Unicode Standard Annex #15. URL: <a
5991 href="http://www.unicode.org/reports/tr15/">http://www.unicode.org/reports/tr15/</a>
5992 </dd>
5993 <!---->
5995 <dt id=UAX29>[UAX29]
5997 <dd>Mark Davis. <a
5998 href="http://www.unicode.org/reports/tr29/"><cite>Unicode Text
5999 Segmentation.</cite></a> 12 September 2012. Unicode Standard Annex #29.
6000 URL: <a
6001 href="http://www.unicode.org/reports/tr29/">http://www.unicode.org/reports/tr29/</a>
6002 </dd>
6003 <!---->
6005 <dt id=UNICODE6>[UNICODE6]
6007 <dd>The Unicode Consortium. <a
6008 href="http://www.unicode.org/versions/Unicode6.2.0/"><cite>The Unicode
6009 Standard, Version 6.2.0.</cite></a> Defined by: The Unicode Standard,
6010 Version 6.2.0 URL: <a
6011 href="http://www.unicode.org/versions/Unicode6.2.0/">http://www.unicode.org/versions/Unicode6.2.0/</a>
6012 </dd>
6013 <!---->
6014 </dl>
6015 <!--end-normative-->
6016 <!--{{!CSS21}}-->
6017 <!--{{!CSS3VAL}}-->
6018 <!--{{!OPENTYPE}}-->
6019 <!--{{!OPENTYPE-FEATURES}}-->
6020 <!--{{!OPEN-FONT-FORMAT}}-->
6021 <!--{{!UNICODE6}}-->
6022 <!--{{!UAX15}}-->
6023 <!--{{!UAX29}}-->
6024 <!--{{!CORS}}-->
6025 <!--{{!HTML5}}-->
6026 <!--{{!CHARMOD}}-->
6028 <h3 class=no-num id=other-references>Other References</h3>
6029 <!--begin-informative-->
6030 <!-- Sorted by label -->
6032 <dl class=bibliography>
6033 <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
6034 <!---->
6036 <dt id=AAT-FEATURES>[AAT-FEATURES]
6038 <dd><a href="http://developer.apple.com/fonts/registry/"><cite>Apple
6039 Advanced Typography font feature registry.</cite></a> Apple. URL: <a
6040 href="http://developer.apple.com/fonts/registry/">http://developer.apple.com/fonts/registry/</a>
6041 </dd>
6042 <!---->
6044 <dt id=ARABIC-TYPO>[ARABIC-TYPO]
6046 <dd>Huda Smitshuijzen AbiFares. <cite>Arabic Typography: A Comprehensive
6047 Sourcebook.</cite> Saqi Books. 2001. ISBN 0-86356-347-3.</dd>
6048 <!---->
6050 <dt id=CHARMOD-NORM>[CHARMOD-NORM]
6052 <dd>François Yergeau; et al. <a
6053 href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/"><cite>Character
6054 Model for the World Wide Web 1.0: Normalization.</cite></a> 1 May 2012.
6055 W3C Working Draft. (Work in progress.) URL: <a
6056 href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/">http://www.w3.org/TR/2012/WD-charmod-norm-20120501/</a>
6057 </dd>
6058 <!---->
6060 <dt id=CJKV-INFO-PROCESSING>[CJKV-INFO-PROCESSING]
6062 <dd>Ken Lunde. <cite>CJKV Information Processing, Second Edition.</cite>
6063 O'Reilly Media, Inc. 2009. ISBN 0-596-51447-1.</dd>
6064 <!---->
6066 <dt id=CSS3-CONDITIONAL>[CSS3-CONDITIONAL]
6068 <dd>L. David Baron. <a
6069 href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/"><cite>CSS
6070 Conditional Rules Module Level 3.</cite></a> 13 December 2012. W3C
6071 Working Draft. (Work in progress.) URL: <a
6072 href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/">http://www.w3.org/TR/2012/WD-css3-conditional-20121213/</a>
6073 </dd>
6074 <!---->
6076 <dt id=CSS3TEXT>[CSS3TEXT]
6078 <dd>Elika J. Etemad; Koji Ishii. <a
6079 href="http://www.w3.org/TR/2012/WD-css3-text-20121113/"><cite>CSS Text
6080 Module Level 3.</cite></a> 13 November 2012. W3C Working Draft. (Work in
6081 progress.) URL: <a
6082 href="http://www.w3.org/TR/2012/WD-css3-text-20121113/">http://www.w3.org/TR/2012/WD-css3-text-20121113/</a>
6083 </dd>
6084 <!---->
6086 <dt id=DIGITAL-TYPOGRAPHY>[DIGITAL-TYPOGRAPHY]
6088 <dd>Richard Rubinstein. <cite>Digital Typography, An Introduction to Type
6089 and Composition for Computer System Design.</cite> Addison-Wesley. 1988.
6090 ISBN 0-201-17633-5.</dd>
6091 <!---->
6093 <dt id=DOM-LEVEL-2-STYLE>[DOM-LEVEL-2-STYLE]
6095 <dd>Chris Wilson; Philippe Le Hégaret; Vidur Apparao. <a
6096 href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/"><cite>Document
6097 Object Model (DOM) Level 2 Style Specification.</cite></a> 13 November
6098 2000. W3C Recommendation. URL: <a
6099 href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/">http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/</a>
6100 </dd>
6101 <!---->
6103 <dt id=ELEMTYPO>[ELEMTYPO]
6105 <dd>Robert Bringhurst. <cite>The Elements of Typographic Style, Version
6106 4.</cite> Hartley & Marks. 2013. ISBN 0-88179-212-8.</dd>
6107 <!---->
6109 <dt id=LANGCULTTYPE>[LANGCULTTYPE]
6111 <dd>John D. Berry, Ed. <cite>Language Culture Type.</cite> Graphis. 2001.
6112 ISBN 1-932026-01-0.</dd>
6113 <!---->
6115 <dt id=OPENTYPE-FONT-GUIDE>[OPENTYPE-FONT-GUIDE]
6117 <dd><a
6118 href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf"><cite>OpenType
6119 User Guide.</cite></a> FontShop International. URL: <a
6120 href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf">https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf</a>
6121 </dd>
6122 <!---->
6124 <dt id=RASTER-TRAGEDY>[RASTER-TRAGEDY]
6126 <dd>Beat Stamm. <a href="http://www.rastertragedy.com/"><cite>The Raster
6127 Tragedy at Low-Resolution Revisited.</cite></a> 7 December 2011. URL: <a
6128 href="http://www.rastertragedy.com/">http://www.rastertragedy.com/</a></dd>
6129 <!---->
6131 <dt id=WINDOWS-GLYPH-PROC>[WINDOWS-GLYPH-PROC]
6133 <dd>John Hudson. <a
6134 href="http://www.microsoft.com/typography/developers/opentype/default.htm"><cite>Windows
6135 Glyph Processing.</cite></a> Microsoft Typogrraphy. URL: <a
6136 href="http://www.microsoft.com/typography/developers/opentype/default.htm">http://www.microsoft.com/typography/developers/opentype/default.htm</a>
6137 </dd>
6138 <!---->
6139 </dl>
6140 <!--end-informative-->
6141 <!--{{ARABIC-TYPO}}-->
6142 <!--{{CJKV-INFO-PROCESSING}}-->
6143 <!--{{DIGITAL-TYPOGRAPHY}}-->
6144 <!--{{DOM-LEVEL-2-STYLE}}-->
6145 <!--{{ELEMTYPO}}-->
6146 <!--{{LANGCULTTYPE}}-->
6147 <!--{{OPENTYPE-FONT-GUIDE}}-->
6148 <!--{{RASTER-TRAGEDY}}-->
6149 <!--{{WINDOWS-GLYPH-PROC}}-->
6150 <!--{{CHARMOD-NORM}}-->
6151 <!--{{AAT-FEATURES}}-->
6152 <!--{{CSS3-CONDITIONAL}}-->
6153 <!--{{CSS3TEXT}}-->
6155 <h2 class=no-num id=index>Index</h2>
6156 <!--begin-index-->
6158 <ul class=indexlist>
6159 <li>100...900 weight values, <a href="#font-weight-numeric-values"
6160 title="100...900 weight values"><strong>3.2</strong></a>
6162 <li><var><absolute-size></var>, <a href="#absolute-size-value"
6163 title="<absolute-size>"><strong>3.5</strong></a>
6165 <li><var><common-lig-values></var>, <a href="#common-lig-values"
6166 title="<common-lig-values>"><strong>6.4</strong></a>
6168 <li><var><contextual-alt-values></var>, <a
6169 href="#contextual-alt-values"
6170 title="<contextual-alt-values>"><strong>6.4</strong></a>
6172 <li><var><discretionary-lig-values></var>, <a
6173 href="#discretionary-lig-values"
6174 title="<discretionary-lig-values>"><strong>6.4</strong></a>
6176 <li><var><east-asian-variant-values></var>, <a
6177 href="#east-asian-variant-values"
6178 title="<east-asian-variant-values>"><strong>6.10</strong></a>
6180 <li><var><east-asian-width-values></var>, <a
6181 href="#east-asian-width-values"
6182 title="<east-asian-width-values>"><strong>6.10</strong></a>
6184 <li><var><family-name></var>, <a href="#family-name-value"
6185 title="<family-name>"><strong>3.1</strong></a>
6187 <li><var><feature-tag-value></var>, <a href="#feature-tag-value"
6188 title="<feature-tag-value>"><strong>6.12</strong></a>
6190 <li><var><font-face-name></var>, <a href="#font-face-name-value"
6191 title="<font-face-name>"><strong>4.3</strong></a>
6193 <li><var><font-variant-css21></var>, <a
6194 href="#font-variant-css21-values"
6195 title="<font-variant-css21>"><strong>3.7</strong></a>
6197 <li><var><generic-family></var>, <a href="#generic-family-value"
6198 title="<generic-family>"><strong>3.1</strong></a>
6200 <li><var><historical-lig-values></var>, <a
6201 href="#historical-lig-values"
6202 title="<historical-lig-values>"><strong>6.4</strong></a>
6204 <li><var><length></var>, <a href="#length-size-value"
6205 title="<length>"><strong>3.5</strong></a>
6207 <li><var><number></var>, <a href="#aspect-ratio-value"
6208 title="<number>"><strong>3.6</strong></a>
6210 <li><var><numeric-figure-values></var>, <a
6211 href="#numeric-figure-values"
6212 title="<numeric-figure-values>"><strong>6.7</strong></a>
6214 <li><var><numeric-fraction-values></var>, <a
6215 href="#numeric-fraction-values"
6216 title="<numeric-fraction-values>"><strong>6.7</strong></a>
6218 <li><var><numeric-spacing-values></var>, <a
6219 href="#numeric-spacing-values"
6220 title="<numeric-spacing-values>"><strong>6.7</strong></a>
6222 <li><var><percentage></var>, <a href="#percentage-size-value"
6223 title="<percentage>"><strong>3.5</strong></a>
6225 <li><var><relative-size></var>, <a href="#relative-size-value"
6226 title="<relative-size>"><strong>3.5</strong></a>
6228 <li><var><string></var>, <a
6229 href="#font-language-override-string-value"
6230 title="<string>"><strong>6.13</strong></a>
6232 <li><var><urange></var>, <a href="#urange-value"
6233 title="<urange>"><strong>4.5</strong></a>
6235 <li><code>@font-face</code>, <a href="#at-font-face-rule"
6236 title="@font-face"><strong>4.1</strong></a>
6238 <li><code>@font-feature-values</code>, <a
6239 href="#at-font-feature-values-rule"
6240 title="@font-feature-values"><strong>6.9</strong></a>
6242 <li>all-petite-caps, <a href="#all-petite-caps"
6243 title=all-petite-caps><strong>6.6</strong></a>
6245 <li>all-small-caps, <a href="#all-small-caps"
6246 title=all-small-caps><strong>6.6</strong></a>
6248 <li>annotation, <a href="#annotation"
6249 title=annotation><strong>6.8</strong></a>
6251 <li>aspect value, <a href="#aspect-value0" title="aspect
6252 value"><strong>3.6</strong></a>
6254 <li>authoring tool, <a href="#authoring-tool" title="authoring
6255 tool"><strong>#</strong></a>
6257 <li>auto
6258 <ul>
6259 <li>font-kerning, <a href="#font-kerning-auto-value" title="auto,
6260 font-kerning"><strong>6.3</strong></a>
6262 <li>font-size-adjust, <a href="#font-size-adjust-auto-value"
6263 title="auto, font-size-adjust"><strong>3.6</strong></a>
6264 </ul>
6266 <li>bold, <a href="#bold" title=bold><strong>3.2</strong></a>
6268 <li>bolder, <a href="#bolder" title=bolder><strong>3.2</strong></a>
6270 <li>character map, <a href="#character-map" title="character
6271 map"><strong>5.2</strong></a>
6273 <li>character-variant, <a href="#character-variant"
6274 title=character-variant><strong>6.8</strong></a>
6276 <li>common-ligatures, <a href="#common-ligatures"
6277 title=common-ligatures><strong>6.4</strong></a>
6279 <li>condensed, <a href="#condensed"
6280 title=condensed><strong>3.3</strong></a>
6282 <li>contextual, <a href="#contextual"
6283 title=contextual><strong>6.4</strong></a>
6285 <li>CSSFontFaceRule, <a href="#cssfontfacerule"
6286 title=CSSFontFaceRule><strong>8.1</strong></a>
6288 <li>CSSFontFeatureValuesRule, <a href="#cssfontfeaturevaluesrule"
6289 title=CSSFontFeatureValuesRule><strong>8.2</strong></a>
6291 <li>cursive, definition of, <a href="#cursive0" title="cursive, definition
6292 of"><strong>#</strong></a>
6294 <li>default face, <a href="#default-face" title="default
6295 face"><strong>5.2</strong></a>
6297 <li>descriptor_declaration, <a href="#descriptordeclaration"
6298 title="descriptor_declaration"><strong>4.1</strong></a>
6300 <li>diagonal-fractions, <a href="#diagonal-fractions"
6301 title=diagonal-fractions><strong>6.7</strong></a>
6303 <li>discretionary-ligatures, <a href="#discretionary-ligatures"
6304 title=discretionary-ligatures><strong>6.4</strong></a>
6306 <li>expanded, <a href="#expanded" title=expanded><strong>3.3</strong></a>
6308 <li>extra-condensed, <a href="#extra-condensed"
6309 title=extra-condensed><strong>3.3</strong></a>
6311 <li>extra-expanded, <a href="#extra-expanded"
6312 title=extra-expanded><strong>3.3</strong></a>
6314 <li>fantasy, definition of, <a href="#fantasy0" title="fantasy, definition
6315 of"><strong>#</strong></a>
6317 <li>feature_type, <a href="#featuretype"
6318 title="feature_type"><strong>6.9</strong></a>
6320 <li>feature_value_block, <a href="#featurevalueblock"
6321 title="feature_value_block"><strong>6.9</strong></a>
6323 <li>feature_value_definition, <a href="#featurevaluedefinition"
6324 title="feature_value_definition"><strong>6.9</strong></a>
6326 <li>font, <a href="#propdef-font" title=font><strong>3.7</strong></a>
6328 <li>font-family
6329 <ul>
6330 <li>descriptor, <a href="#descdef-font-family" title="font-family,
6331 descriptor"><strong>4.2</strong></a>
6333 <li>property, <a href="#propdef-font-family" title="font-family,
6334 property"><strong>3.1</strong></a>
6335 </ul>
6337 <li>font-feature-settings
6338 <ul>
6339 <li>descriptor, <a href="#descdef-font-feature-settings"
6340 title="font-feature-settings, descriptor"><strong>4.7</strong></a>
6342 <li>property, <a href="#propdef-font-feature-settings"
6343 title="font-feature-settings, property"><strong>6.12</strong></a>
6344 </ul>
6346 <li>font-kerning, <a href="#propdef-font-kerning"
6347 title=font-kerning><strong>6.3</strong></a>
6349 <li>font-language-override, <a href="#propdef-font-language-override"
6350 title=font-language-override><strong>6.13</strong></a>
6352 <li>font-size, <a href="#propdef-font-size"
6353 title=font-size><strong>3.5</strong></a>
6355 <li>font-size-adjust, <a href="#propdef-font-size-adjust"
6356 title=font-size-adjust><strong>3.6</strong></a>
6358 <li>font-stretch
6359 <ul>
6360 <li>descriptor, <a href="#descdef-font-stretch" title="font-stretch,
6361 descriptor"><strong>4.4</strong></a>
6363 <li>property, <a href="#propdef-font-stretch" title="font-stretch,
6364 property"><strong>3.3</strong></a>
6365 </ul>
6367 <li>font-style
6368 <ul>
6369 <li>descriptor, <a href="#descdef-font-style" title="font-style,
6370 descriptor"><strong>4.4</strong></a>
6372 <li>property, <a href="#propdef-font-style" title="font-style,
6373 property"><strong>3.4</strong></a>
6374 </ul>
6376 <li>font-synthesis, <a href="#propdef-font-synthesis"
6377 title=font-synthesis><strong>3.8</strong></a>
6379 <li>font-variant
6380 <ul>
6381 <li>descriptor, <a href="#descdef-font-variant" title="font-variant,
6382 descriptor"><strong>4.7</strong></a>
6384 <li>property, <a href="#propdef-font-variant" title="font-variant,
6385 property"><strong>6.11</strong></a>
6386 </ul>
6388 <li>font-variant-alternates, <a href="#propdef-font-variant-alternates"
6389 title=font-variant-alternates><strong>6.8</strong></a>
6391 <li>font-variant-caps, <a href="#propdef-font-variant-caps"
6392 title=font-variant-caps><strong>6.6</strong></a>
6394 <li>font-variant-east-asian, <a href="#propdef-font-variant-east-asian"
6395 title=font-variant-east-asian><strong>6.10</strong></a>
6397 <li>font-variant-ligatures, <a href="#propdef-font-variant-ligatures"
6398 title=font-variant-ligatures><strong>6.4</strong></a>
6400 <li>font-variant-numeric, <a href="#propdef-font-variant-numeric"
6401 title=font-variant-numeric><strong>6.7</strong></a>
6403 <li>font-variant-position, <a href="#propdef-font-variant-position"
6404 title=font-variant-position><strong>6.5</strong></a>
6406 <li>font-weight
6407 <ul>
6408 <li>descriptor, <a href="#descdef-font-weight" title="font-weight,
6409 descriptor"><strong>4.4</strong></a>
6411 <li>property, <a href="#propdef-font-weight" title="font-weight,
6412 property"><strong>3.2</strong></a>
6413 </ul>
6415 <li>font_face_rule, <a href="#fontfacerule"
6416 title="font_face_rule"><strong>4.1</strong></a>
6418 <li>FONT_FACE_SYM, <a href="#fontfacesym"
6419 title="FONT_FACE_SYM"><strong>4.1</strong></a>
6421 <li>font_family_name, <a href="#fontfamilyname"
6422 title="font_family_name"><strong>6.9</strong></a>
6424 <li>font_family_name_list, <a href="#fontfamilynamelist"
6425 title="font_family_name_list"><strong>6.9</strong></a>
6427 <li>font_feature_values_rule, <a href="#fontfeaturevaluesrule"
6428 title="font_feature_values_rule"><strong>6.9</strong></a>
6430 <li>FONT_FEATURE_VALUES_SYM, <a href="#fontfeaturevaluessym"
6431 title="FONT_FEATURE_VALUES_SYM"><strong>6.9</strong></a>
6433 <li>full-width, <a href="#full-width"
6434 title=full-width><strong>6.10</strong></a>
6436 <li>historical-forms, <a href="#historical-forms"
6437 title=historical-forms><strong>6.8</strong></a>
6439 <li>historical-ligatures, <a href="#historical-ligatures"
6440 title=historical-ligatures><strong>6.4</strong></a>
6442 <li>italic, <a href="#italic" title=italic><strong>3.4</strong></a>
6444 <li>jis04, <a href="#jis04" title=jis04><strong>6.10</strong></a>
6446 <li>jis78, <a href="#jis78" title=jis78><strong>6.10</strong></a>
6448 <li>jis83, <a href="#jis83" title=jis83><strong>6.10</strong></a>
6450 <li>jis90, <a href="#jis90" title=jis90><strong>6.10</strong></a>
6452 <li>lighter, <a href="#lighter" title=lighter><strong>3.2</strong></a>
6454 <li>lining-nums, <a href="#lining-nums"
6455 title=lining-nums><strong>6.7</strong></a>
6457 <li>monospace, definition of, <a href="#monospace0" title="monospace,
6458 definition of"><strong>#</strong></a>
6460 <li>no-common-ligatures, <a href="#no-common-ligatures"
6461 title=no-common-ligatures><strong>6.4</strong></a>
6463 <li>no-contextual, <a href="#no-contextual"
6464 title=no-contextual><strong>6.4</strong></a>
6466 <li>no-discretionary-ligatures, <a href="#no-discretionary-ligatures"
6467 title=no-discretionary-ligatures><strong>6.4</strong></a>
6469 <li>no-historical-ligatures, <a href="#no-historical-ligatures"
6470 title=no-historical-ligatures><strong>6.4</strong></a>
6472 <li>none
6473 <ul>
6474 <li>font-kerning, <a href="#font-kerning-none-value" title="none,
6475 font-kerning"><strong>6.3</strong></a>
6477 <li>font-size-adjust, <a href="#font-size-adjust-none-value"
6478 title="none, font-size-adjust"><strong>3.6</strong></a>
6480 <li>font-variant, <a href="#font-variant-none-value" title="none,
6481 font-variant"><strong>6.11</strong></a>
6483 <li>font-variant-ligatures, <a href="#font-variant-ligatures-none-value"
6484 title="none, font-variant-ligatures"><strong>6.4</strong></a>
6485 </ul>
6487 <li>normal, <a href="#normal" title=normal><strong>6.5</strong></a>
6488 <ul>
6489 <li>font-feature-settings, <a href="#font-feature-settings-normal-value"
6490 title="normal, font-feature-settings"><strong>6.12</strong></a>
6492 <li>font-kerning, <a href="#font-kerning-normal-value" title="normal,
6493 font-kerning"><strong>6.3</strong></a>
6495 <li>font-language-override, <a
6496 href="#font-language-override-normal-value" title="normal,
6497 font-language-override"><strong>6.13</strong></a>
6499 <li>font-stretch, <a href="#font-stretch-normal-value" title="normal,
6500 font-stretch"><strong>3.3</strong></a>
6502 <li>font-style, <a href="#font-style-normal-value" title="normal,
6503 font-style"><strong>3.4</strong></a>
6505 <li>font-variant, <a href="#font-variant-normal-value" title="normal,
6506 font-variant"><strong>6.11</strong></a>
6508 <li>font-variant-alternates, <a
6509 href="#font-variant-alternates-normal-value" title="normal,
6510 font-variant-alternates"><strong>6.8</strong></a>
6512 <li>font-variant-caps, <a href="#font-variant-caps-normal-value"
6513 title="normal, font-variant-caps"><strong>6.6</strong></a>
6515 <li>font-variant-east-asian, <a
6516 href="#font-variant-east-asian-normal-value" title="normal,
6517 font-variant-east-asian"><strong>6.10</strong></a>
6519 <li>font-variant-ligatures, <a
6520 href="#font-variant-ligatures-normal-value" title="normal,
6521 font-variant-ligatures"><strong>6.4</strong></a>
6523 <li>font-variant-numeric, <a href="#font-variant-numeric-normal-value"
6524 title="normal, font-variant-numeric"><strong>6.7</strong></a>
6526 <li>font-weight, <a href="#font-weight-normal-value" title="normal,
6527 font-weight"><strong>3.2</strong></a>
6528 </ul>
6530 <li>oblique, <a href="#oblique" title=oblique><strong>3.4</strong></a>
6532 <li>oldstyle-nums, <a href="#oldstyle-nums"
6533 title=oldstyle-nums><strong>6.7</strong></a>
6535 <li>ordinal, <a href="#ordinal" title=ordinal><strong>6.7</strong></a>
6537 <li>ornaments, <a href="#ornaments"
6538 title=ornaments><strong>6.8</strong></a>
6540 <li>petite-caps, <a href="#petite-caps"
6541 title=petite-caps><strong>6.6</strong></a>
6543 <li>proportional-nums, <a href="#proportional-nums"
6544 title=proportional-nums><strong>6.7</strong></a>
6546 <li>proportional-width, <a href="#proportional-width"
6547 title=proportional-width><strong>6.10</strong></a>
6549 <li>renderer, <a href="#renderer" title=renderer><strong>#</strong></a>
6551 <li>ruby, <a href="#ruby" title=ruby><strong>6.10</strong></a>
6553 <li>sans-serif, definition of, <a href="#sans-serif0" title="sans-serif,
6554 definition of"><strong>#</strong></a>
6556 <li>semi-condensed, <a href="#semi-condensed-"
6557 title=semi-condensed><strong>3.3</strong></a>
6559 <li>semi-expanded, <a href="#semi-expanded"
6560 title=semi-expanded><strong>3.3</strong></a>
6562 <li>serif, definition of, <a href="#serif0" title="serif, definition
6563 of"><strong>#</strong></a>
6565 <li>simplified, <a href="#simplified"
6566 title=simplified><strong>6.10</strong></a>
6568 <li>slashed-zero, <a href="#slashed-zero"
6569 title=slashed-zero><strong>6.7</strong></a>
6571 <li>small-caps, <a href="#small-caps"
6572 title=small-caps><strong>6.6</strong></a>
6574 <li>src, <a href="#descdef-src" title=src><strong>4.3</strong></a>
6576 <li>stacked-fractions, <a href="#stacked-fractions"
6577 title=stacked-fractions><strong>6.7</strong></a>
6579 <li>style sheet
6580 <ul>
6581 <li>as conformance class, <a href="#style-sheet" title="style sheet, as
6582 conformance class"><strong>#</strong></a>
6583 </ul>
6585 <li>styleset, <a href="#styleset" title=styleset><strong>6.8</strong></a>
6587 <li>stylistic, <a href="#stylistic"
6588 title=stylistic><strong>6.8</strong></a>
6590 <li>sub, <a href="#sub" title=sub><strong>6.5</strong></a>
6592 <li>super, <a href="#super" title=super><strong>6.5</strong></a>
6594 <li>swash, <a href="#swash" title=swash><strong>6.8</strong></a>
6596 <li>tabular-nums, <a href="#tabular-nums"
6597 title=tabular-nums><strong>6.7</strong></a>
6599 <li>titling-caps, <a href="#titling-caps"
6600 title=titling-caps><strong>6.6</strong></a>
6602 <li>traditional, <a href="#traditional"
6603 title=traditional><strong>6.10</strong></a>
6605 <li>ultra-condensed, <a href="#ultra-condensed"
6606 title=ultra-condensed><strong>3.3</strong></a>
6608 <li>ultra-expanded, <a href="#ultra-expanded"
6609 title=ultra-expanded><strong>3.3</strong></a>
6611 <li>unicase, <a href="#unicase" title=unicase><strong>6.6</strong></a>
6613 <li>unicode-range, <a href="#descdef-unicode-range"
6614 title=unicode-range><strong>4.5</strong></a>
6616 <li>weight, <a href="#weight" title=weight><strong>2</strong></a>
6618 <li>width, <a href="#width" title=width><strong>2</strong></a>
6619 </ul>
6620 <!--end-index-->
6622 <h2 class=no-num id=property-index>Property index</h2>
6623 <!--begin-properties-->
6625 <table class=proptable>
6626 <thead>
6627 <tr>
6628 <th>Property
6630 <th>Values
6632 <th>Initial
6634 <th>Applies to
6636 <th>Inh.
6638 <th>Percentages
6640 <th>Media
6642 <tbody>
6643 <tr>
6644 <th><a class=property href="#propdef-font">font</a>
6646 <td>[ [ <‘font-style’> || <font-variant-css21> ||
6647 <‘font-weight’> || <‘font-stretch’ ]?
6648 <‘font-size’> [ / <‘line-height’> ]?
6649 <‘font-family’> ] | caption | icon | menu | message-box |
6650 small-caption | status-bar
6652 <td>see individual properties
6654 <td>all elements
6656 <td>yes
6658 <td>see individual properties
6660 <td>visual
6662 <tr>
6663 <th><span class=property>font-family</span>
6665 <td>[ <family-name> | <generic-family> ] #
6667 <td>depends on user agent
6669 <td>all elements
6671 <td>yes
6673 <td>N/A
6675 <td>visual
6677 <tr>
6678 <th><span class=property>font-feature-settings</span>
6680 <td>normal | <feature-tag-value> #
6682 <td>normal
6684 <td>all elements
6686 <td>yes
6688 <td>N/A
6690 <td>visual
6692 <tr>
6693 <th><a class=property href="#propdef-font-kerning">font-kerning</a>
6695 <td>auto | normal | none
6697 <td>auto
6699 <td>all elements
6701 <td>yes
6703 <td>N/A
6705 <td>visual
6707 <tr>
6708 <th><a class=property
6709 href="#propdef-font-language-override">font-language-override</a>
6711 <td>normal | <string>
6713 <td>normal
6715 <td>all elements
6717 <td>yes
6719 <td>N/A
6721 <td>visual
6723 <tr>
6724 <th><a class=property href="#propdef-font-size">font-size</a>
6726 <td><absolute-size> | <relative-size> | <length> |
6727 <percentage>
6729 <td>medium
6731 <td>all elements
6733 <td>yes
6735 <td>refer to parent element's font size
6737 <td>visual
6739 <tr>
6740 <th><a class=property
6741 href="#propdef-font-size-adjust">font-size-adjust</a>
6743 <td>none | auto | <number>
6745 <td>none
6747 <td>all elements
6749 <td>yes
6751 <td>N/A
6753 <td>visual
6755 <tr>
6756 <th><span class=property>font-stretch</span>
6758 <td>normal | ultra-condensed | extra-condensed | condensed |
6759 semi-condensed | semi-expanded | expanded | extra-expanded |
6760 ultra-expanded
6762 <td>normal
6764 <td>all elements
6766 <td>yes
6768 <td>N/A
6770 <td>visual
6772 <tr>
6773 <th><span class=property>font-style</span>
6775 <td>normal | italic | oblique
6777 <td>normal
6779 <td>all elements
6781 <td>yes
6783 <td>N/A
6785 <td>visual
6787 <tr>
6788 <th><a class=property href="#propdef-font-synthesis">font-synthesis</a>
6790 <td>none | [ weight || style ]
6792 <td>weight style
6794 <td>all elements
6796 <td>yes
6798 <td>N/A
6800 <td>visual
6802 <tr>
6803 <th><span class=property>font-variant</span>
6805 <td>normal | none | [ <common-lig-values> ||
6806 <discretionary-lig-values> || <historical-lig-values> ||
6807 <contextual-alt-values> || stylistic(<feature-value-name>)
6808 || historical-forms || styleset(<feature-value-name> #) ||
6809 character-variant(<feature-value-name> #) ||
6810 swash(<feature-value-name>) ||
6811 ornaments(<feature-value-name>) ||
6812 annotation(<feature-value-name>) || [ small-caps | all-small-caps
6813 | petite-caps | all-petite-caps | unicase | titling-caps ] ||
6814 <numeric-figure-values> || <numeric-spacing-values> ||
6815 <numeric-fraction-values> || ordinal || slashed-zero ||
6816 <east-asian-variant-values> || <east-asian-width-values> ||
6817 ruby ]
6819 <td>normal
6821 <td>all elements
6823 <td>yes
6825 <td>see individual properties
6827 <td>visual
6829 <tr>
6830 <th><a class=property
6831 href="#propdef-font-variant-alternates">font-variant-alternates</a>
6833 <td>normal | [ stylistic(<feature-value-name>) || historical-forms
6834 || styleset(<feature-value-name> #) ||
6835 character-variant(<feature-value-name> #) ||
6836 swash(<feature-value-name>) ||
6837 ornaments(<feature-value-name>) ||
6838 annotation(<feature-value-name>) ]
6840 <td>normal
6842 <td>all elements
6844 <td>yes
6846 <td>N/A
6848 <td>visual
6850 <tr>
6851 <th><a class=property
6852 href="#propdef-font-variant-caps">font-variant-caps</a>
6854 <td>normal | small-caps | all-small-caps | petite-caps | all-petite-caps
6855 | unicase | titling-caps
6857 <td>normal
6859 <td>all elements
6861 <td>yes
6863 <td>N/A
6865 <td>visual
6867 <tr>
6868 <th><a class=property
6869 href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
6871 <td>normal | [ <east-asian-variant-values> ||
6872 <east-asian-width-values> || ruby ]
6874 <td>normal
6876 <td>all elements
6878 <td>yes
6880 <td>N/A
6882 <td>visual
6884 <tr>
6885 <th><a class=property
6886 href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
6888 <td>normal | none | [ <common-lig-values> ||
6889 <discretionary-lig-values> || <historical-lig-values> ||
6890 <contextual-alt-values> ]
6892 <td>normal
6894 <td>all elements
6896 <td>yes
6898 <td>N/A
6900 <td>visual
6902 <tr>
6903 <th><a class=property
6904 href="#propdef-font-variant-numeric">font-variant-numeric</a>
6906 <td>normal | [ <numeric-figure-values> ||
6907 <numeric-spacing-values> || <numeric-fraction-values> ||
6908 ordinal || slashed-zero ]
6910 <td>normal
6912 <td>all elements
6914 <td>yes
6916 <td>N/A
6918 <td>visual
6920 <tr>
6921 <th><a class=property
6922 href="#propdef-font-variant-position">font-variant-position</a>
6924 <td>normal | sub | super
6926 <td>normal
6928 <td>all elements
6930 <td>yes
6932 <td>N/A
6934 <td>visual
6936 <tr>
6937 <th><span class=property>font-weight</span>
6939 <td>normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600
6940 | 700 | 800 | 900
6942 <td>normal
6944 <td>all elements
6946 <td>yes
6948 <td>N/A
6950 <td>visual
6951 </table>
6952 <!--end-properties-->
6953 <!--begin-descriptors-->
6955 <table class=proptable>
6956 <thead>
6957 <tr>
6958 <th>Descriptor
6960 <th>Value
6962 <th>Initial
6964 <th>Percentages
6966 <th>Media
6968 <tbody>
6969 <tr>
6970 <th><span class=property>font-family</span>
6972 <td><family-name>
6974 <td>N/A
6976 <tr>
6977 <th><span class=property>font-feature-settings</span>
6979 <td>normal | <feature-tag-value> #
6981 <td>normal
6983 <tr>
6984 <th><span class=property>font-stretch</span>
6986 <td>normal | ultra-condensed | extra-condensed | condensed |
6987 semi-condensed | semi-expanded | expanded | extra-expanded |
6988 ultra-expanded
6990 <td>normal
6992 <tr>
6993 <th><span class=property>font-style</span>
6995 <td>normal | italic | oblique
6997 <td>normal
6999 <tr>
7000 <th><span class=property>font-variant</span>
7002 <td>normal | none | [ <common-lig-values> ||
7003 <discretionary-lig-values> || <historical-lig-values> ||
7004 <contextual-alt-values> || stylistic(<feature-value-name>)
7005 || historical-forms || styleset(<feature-value-name> #) ||
7006 character-variant(<feature-value-name> #) ||
7007 swash(<feature-value-name>) ||
7008 ornaments(<feature-value-name>) ||
7009 annotation(<feature-value-name>) || [ small-caps | all-small-caps
7010 | petite-caps | all-petite-caps | unicase | titling-caps ] ||
7011 <numeric-figure-values> || <numeric-spacing-values> ||
7012 <numeric-fraction-values> || ordinal || slashed-zero ||
7013 <east-asian-variant-values> || <east-asian-width-values> ||
7014 ruby ]
7016 <td>normal
7018 <tr>
7019 <th><span class=property>font-weight</span>
7021 <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
7023 <td>normal
7025 <tr>
7026 <th><a class=property href="#descdef-src">src</a>
7028 <td>[ <url> [format(<string> #)]? | <font-face-name> ] #
7030 <td>N/A
7032 <tr>
7033 <th><a class=property href="#descdef-unicode-range">unicode-range</a>
7035 <td><urange> #
7037 <td>U+0-10FFFF
7038 </table>
7039 <!--end-descriptors-->
7040 <script type="text/javascript">
7041 window.onload = function () {
7042 if (!("devicePixelRatio" in window && window.devicePixelRatio > 1)) return;
7043 var i, hiresElements = document.getElementsByClassName("hires");
7044 for (i = 0; i < hiresElements.length; i++) {
7045 var h = hiresElements[i];
7046 if (h.tagName != "IMG") continue;
7047 var src = h.getAttribute("src");
7048 var src2x = src.replace(/\.\w+$/, function(m) { return "@2x" + m; });
7049 h.src = src2x;
7050 }
7051 }
7052 </script>
7053 </html>
7054 <!-- Keep this comment at the end of the file
7055 Local variables:
7056 mode: sgml
7057 sgml-declaration:"~/SGML/HTML4.decl"
7058 sgml-default-doctype-name:"html"
7059 sgml-minimize-attributes:t
7060 sgml-nofill-elements:("pre" "style" "br")
7061 sgml-live-element-indicator:t
7062 sgml-omittag:nil
7063 sgml-shorttag:nil
7064 sgml-namecase-general:t
7065 sgml-general-insert-case:lower
7066 sgml-always-quote-attributes:t
7067 sgml-indent-step:nil
7068 sgml-indent-data:t
7069 sgml-parent-document:nil
7070 sgml-exposed-tags:nil
7071 sgml-local-catalogs:nil
7072 sgml-local-ecat-files:nil
7073 End:
7074 -->
7075 <!--
7077 to do:
7079 - wording of OpenType family name handling
7080 - handling combining sequences in the font matching algorithm
7081 - fix-up fi ligature example
7083 -->
