css-fonts/Fonts.html@830aa2109226
css-fonts/Fonts.html
Thu, 30 May 2013 16:25:34 +0900
- author
- John Daggett <jdaggett@mozilla.com>
- date
- Thu, 30 May 2013 16:25:34 +0900
- changeset 8278
- 830aa2109226
- parent 8277
- a09de2f3e565
- child 8279
- a548c37dce4c
- permissions
- -rw-r--r--
[css-fonts] clean up intraspec links
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-30-may-2013>Editor's Draft 30
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-20130530/">http://www.w3.org/TR/2013/ED-css3-fonts-20130530/</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 (‘<code class=property>normal</code>’).
1910 Notice that the font family name "new century schoolbook", which contains
1911 spaces, is enclosed in quotes. The fourth rule sets the <a
1912 href="#propdef-font-weight" title="font-weight!!property">‘<code
1913 class=property>font-weight</code>’</a> to ‘<a href="#bold"><code
1914 class=property>bold</code></a>’, the <a href="#propdef-font-style"
1915 title="font-style!!property">‘<code
1916 class=property>font-style</code>’</a> to ‘<a href="#italic"><code
1917 class=property>italic</code></a>’, and implicitly sets <a
1918 href="#propdef-font-variant" title="font-variant!!property">‘<code
1919 class=property>font-variant</code>’</a> to ‘<code
1920 class=property>normal</code>’.
1922 <p> The fifth rule sets the <a href="#propdef-font-variant"
1923 title="font-variant!!property">‘<code
1924 class=property>font-variant</code>’</a> (‘<a href="#small-caps"><code
1925 class=property>small-caps</code></a>’), the <span class=property>‘<a
1926 href="#propdef-font-size"><code
1927 class=property>font-size</code></a>’</span> (120% of the parent's font
1928 size), the <a class=property
1929 href="http://www.w3.org/TR/CSS2/visudet.html#propdef-line-height">‘<code
1930 class=property>line-height</code>’</a> (120% of the font size) and the
1931 <a href="#propdef-font-family" title="font-family!!property">‘<code
1932 class=property>font-family</code>’</a> (‘<a href="#fantasy"><code
1933 class=property>fantasy</code></a>’). It follows that the keyword
1934 ‘<code class=property>normal</code>’ applies to the two remaining
1935 properties: <a href="#propdef-font-style"
1936 title="font-style!!property">‘<code
1937 class=property>font-style</code>’</a> and <a
1938 href="#propdef-font-weight" title="font-weight!!property">‘<code
1939 class=property>font-weight</code>’</a>.
1941 <p>The sixth rule sets the <a href="#propdef-font-style"
1942 title="font-style!!property">‘<code
1943 class=property>font-style</code>’</a>, <a href="#propdef-font-stretch"
1944 title="font-stretch!!property">‘<code
1945 class=property>font-stretch</code>’</a>, <span class=property>‘<a
1946 href="#propdef-font-size"><code
1947 class=property>font-size</code></a>’</span>, and <a
1948 href="#propdef-font-family" title="font-family!!property">‘<code
1949 class=property>font-family</code>’</a>, the other font properties being
1950 set to their initial values.
1951 </div>
1953 <p>Since the <a href="#propdef-font-stretch"
1954 title="font-stretch!!property">‘<code
1955 class=property>font-stretch</code>’</a> property was not defined in CSS
1956 2.1, when using <a href="#propdef-font-stretch"
1957 title="font-stretch!!property">‘<code
1958 class=property>font-stretch</code>’</a> values within ‘<a
1959 href="#propdef-font"><code class=property>font</code></a>’ rules,
1960 authors should include a extra version compatible with older user agents:
1962 <pre>p {
1963 font: 80% sans-serif; /* for older user agents */
1964 font: condensed 80% sans-serif;
1965 }</pre>
1967 <p>The following values refer to system fonts:
1969 <dl>
1970 <dt><strong>caption</strong>
1972 <dd>The font used for captioned controls (e.g., buttons, drop-downs,
1973 etc.).
1975 <dt><strong>icon</strong>
1977 <dd>The font used to label icons.
1979 <dt><strong>menu</strong>
1981 <dd>The font used in menus (e.g., dropdown menus and menu lists).
1983 <dt><strong>message-box</strong>
1985 <dd>The font used in dialog boxes.
1987 <dt><strong>small-caption</strong>
1989 <dd>The font used for labeling small controls.
1991 <dt><strong>status-bar</strong>
1993 <dd>The font used in window status bars.
1994 </dl>
1996 <p>System fonts may only be set as a whole; that is, the font family, size,
1997 weight, style, etc. are all set at the same time. These values may then be
1998 altered individually if desired. If no font with the indicated
1999 characteristics exists on a given platform, the user agent should either
2000 intelligently substitute (e.g., a smaller version of the ‘<code
2001 class=property>caption</code>’ font might be used for the ‘<code
2002 class=property>small-caption</code>’ font), or substitute a user agent
2003 default font. As for regular fonts, if, for a system font, any of the
2004 individual properties are not part of the operating system's available
2005 user preferences, those properties should be set to their initial values.
2007 <p>That is why this property is "almost" a shorthand property: system fonts
2008 can only be specified with this property, not with <a
2009 href="#propdef-font-family" title="font-family!!property">‘<code
2010 class=property>font-family</code>’</a> itself, so <span
2011 class=property>‘<a href="#propdef-font"><code
2012 class=property>font</code></a>’</span> allows authors to do more than
2013 the sum of its subproperties. However, the individual properties such as
2014 <a href="#propdef-font-weight" title="font-weight!!property">‘<code
2015 class=property>font-weight</code>’</a> are still given values taken from
2016 the system font, which can be independently varied.
2018 <p>Note that the keywords used for the system fonts listed above are only
2019 treated as keywords when they occur in the initial position, in other
2020 positions the same string is treated as part of the font family name:
2022 <pre> font: menu; /* use the font settings for system menus */
2023 font: large menu; /* use a font family named "menu" */</pre>
2025 <div class=example>
2026 <p style="display:none">Example(s):
2028 <p>
2030 <pre>button { font: 300 italic 1.3em/1.7em "FB Armada", sans-serif }
2031 button p { font: menu }
2032 button p em { font-weight: bolder }
2033 </pre>
2035 <p>If the font used for dropdown menus on a particular system happened to
2036 be, for example, 9-point Charcoal, with a weight of 600, then P elements
2037 that were descendants of BUTTON would be displayed as if this rule were
2038 in effect:
2040 <pre>button p { font: 600 9pt Charcoal }
2041 </pre>
2043 <p>Because the <span class=property>‘<a href="#propdef-font"><code
2044 class=property>font</code></a>’</span> shorthand resets to its initial
2045 value any property not explicitly given a value, this has the same effect
2046 as this declaration:
2048 <pre>button p {
2049 font-style: normal;
2050 font-variant: normal;
2051 font-weight: 600;
2052 font-size: 9pt;
2053 line-height: normal;
2054 font-family: Charcoal
2055 }
2056 </pre>
2057 </div>
2058 <!-- prop: font-synthesis -->
2060 <h3 id=font-synthesis-prop><span class=secno>3.8 </span>Controlling
2061 synthetic faces: the <a href="#propdef-font-synthesis">font-synthesis</a>
2062 property</h3>
2064 <table class=propdef id=namefont-synthesisvaluenone-weight-style>
2065 <tbody>
2066 <tr>
2067 <td>Name:
2069 <td><dfn id=propdef-font-synthesis>font-synthesis</dfn>
2071 <tr>
2072 <td>Value:
2074 <td>none | [ weight || style ]
2076 <tr>
2077 <td>Initial:
2079 <td>weight style
2081 <tr>
2082 <td>Applies to:
2084 <td>all elements
2086 <tr>
2087 <td>Inherited:
2089 <td>yes
2091 <tr>
2092 <td>Percentages:
2094 <td>N/A
2096 <tr>
2097 <td>Media:
2099 <td>visual
2101 <tr>
2102 <td>Computed value:
2104 <td>as specified
2106 <tr>
2107 <td>Animatable:
2109 <td>no
2110 </table>
2112 <p>This property controls whether user agents are allowed to synthesize
2113 bold or oblique font faces when a font family lacks bold or italic faces.
2114 If ‘<a href="#weight"><code class=property>weight</code></a>’ is not
2115 specified, user agents must not synthesize bold faces and if ‘<code
2116 class=property>style</code>’ is not specified user agents must not
2117 synthesize italic faces. A value of ‘<code class=property>none</code>’
2118 disallows all synthetic faces.
2120 <div class=example>
2121 <p>The style rule below disables the use of synthetically obliqued Arabic:</p>
2123 <pre>*:lang(ar) { font-synthesis: none; }
2124 </pre>
2125 </div>
2127 <h2 id=font-resources><span class=secno>4 </span>Font Resources</h2>
2129 <h3 id=font-face-rule><span class=secno>4.1 </span>The
2130 <code>@font-face</code> rule</h3>
2132 <p>The <code>@font-face</code> rule allows for linking to fonts that are
2133 automatically fetched and activated when needed. This allows authors to
2134 select a font that closely matches the design goals for a given page
2135 rather than limiting the font choice to a set of fonts available on all
2136 platforms. A set of font descriptors define the location of a font
2137 resource, either locally or externally, along with the style
2138 characteristics of an individual face. Multiple <code>@font-face</code>
2139 rules can be used to construct font families with a variety of faces.
2140 Using CSS font matching rules, a user agent can selectively download only
2141 those faces that are needed for a given piece of text.
2143 <p>The @font-face rule consists of the @font-face at-keyword followed by a
2144 block of descriptor declarations. In terms of the grammar, this
2145 specification defines the following productions:
2147 <pre><dfn id=fontfacerule>font_face_rule</dfn>
2148 : <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>*
2149 ;
2151 <dfn id=descriptordeclaration>descriptor_declaration</dfn>
2152 : <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>
2153 ;</pre>
2155 <p>The following new definitions are introduced:
2157 <pre>- -|\\0{0,4}2d(\r\n|[ \t\r\n\f])?
2158 F f|\\0{0,4}(46|66)(\r\n|[ \t\r\n\f])?</pre>
2160 <p>The following new token is introduced:
2162 <pre>@{F}{O}{N}{T}{-}{F}{A}{C}{E} {return <dfn id=fontfacesym>FONT_FACE_SYM</dfn>;}</pre>
2164 <p>Each <span class=index-inst id=font-face
2165 title="@font-face"><code>@font-face</code></span> rule specifies a value
2166 for every font descriptor, either implicitly or explicitly. Those not
2167 given explicit values in the rule take the initial value listed with each
2168 descriptor in this specification. These descriptors apply solely within
2169 the context of the <code>@font-face</code> rule in which they are defined,
2170 and do not apply to document language elements. There is no notion of
2171 which elements the descriptors apply to or whether the values are
2172 inherited by child elements. When a given descriptor occurs multiple times
2173 in a given <code>@font-face</code> rule, only the last descriptor
2174 declaration is used and all prior declarations for that descriptor are
2175 ignored.
2177 <div class=example>
2178 <p>To use a downloadable font called Gentium:</p>
2180 <pre>
2181 @font-face {
2182 font-family: Gentium;
2183 src: url(http://example.com/fonts/Gentium.ttf);
2184 }
2186 p { font-family: Gentium, serif; }
2187 </pre>
2189 <p>The user agent will download Gentium and use it when rendering text
2190 within paragraph elements. If for some reason the site serving the font
2191 is unavailable, the default serif font will be used.</p>
2192 </div>
2194 <p>A given set of <code>@font-face</code> rules define a set of fonts
2195 available for use within the documents that contain these rules. When font
2196 matching is done, fonts defined using these rules are considered before
2197 other available fonts on a system.
2199 <p>Downloaded fonts are only available to documents that reference them.
2200 The process of activating these fonts must not make them available to
2201 other applications or to documents that don't directly link to the same
2202 font. User agent implementers might consider it convenient to use
2203 downloaded fonts when rendering characters in other documents for which no
2204 other available font exists as part of the system font fallback procedure.
2205 However, this would cause a security leak since the contents of one page
2206 would be able to affect other pages, something an attacker could use as an
2207 attack vector. These restrictions do not affect caching behavior, fonts
2208 are cached the same way other web resources are cached.
2210 <p>This at-rule follows the forward-compatible parsing rules of CSS. Like
2211 properties in a declaration block, declarations of any descriptors that
2212 are not supported by the user agent must be ignored.
2213 <code>@font-face</code> rules require a font-family and src descriptor; if
2214 either of these are missing, the <code>@font-face</code> rule is invalid
2215 and must be ignored entirely.
2217 <p>In cases where user agents have limited platform resources or implement
2218 the ability to disable downloadable font resources,
2219 <code>@font-face</code> rules must simply be ignored; the behavior of
2220 individual descriptors as defined in this specification should not be
2221 altered.
2223 <h3 id=font-family-desc><span class=secno>4.2 </span>Font family: the <a
2224 href="#descdef-font-family">font-family</a> descriptor</h3>
2226 <table class=descdef>
2227 <tbody>
2228 <tr>
2229 <td>Name:
2231 <td><dfn id=descdef-font-family
2232 title="font-family!!descriptor">font-family</dfn>
2234 <tr>
2235 <td>Value:
2237 <td><a href="#family-name-value"><var><family-name></var></a>
2239 <tr>
2240 <td><em>Initial:</em>
2242 <td>N/A
2243 </table>
2245 <p>This descriptor defines the font family name that will be used in all
2246 CSS font family name matching. It is required for the @font-face rule to
2247 be valid. It overrides the font family names contained in the underlying
2248 font data. If the font family name is the same as a font family available
2249 in a given user's environment, it effectively hides the underlying font
2250 for documents that use the stylesheet. This permits a web author to freely
2251 choose font-family names without worrying about conflicts with font family
2252 names present in a given user's environment. Likewise, platform
2253 substitutions for a given font family name must not be used.
2255 <h3 id=src-desc><span class=secno>4.3 </span>Font reference: the <a
2256 href="#descdef-src">src</a> descriptor</h3>
2258 <table class=descdef>
2259 <tbody>
2260 <tr>
2261 <td>Name:
2263 <td><dfn id=descdef-src>src</dfn>
2265 <tr>
2266 <td>Value:
2268 <td>[ <url> [format(<string> #)]? | <a
2269 href="#font-face-name-value"><var><font-face-name></var></a> ] #
2271 <tr>
2272 <td><em>Initial:</em>
2274 <td>N/A
2275 </table>
2277 <p>This descriptor specifies the resource containing font data. It is
2278 required for the <code>@font-face</code> rule to be valid. Its value is a
2279 prioritized, comma-separated list of external references or
2280 locally-installed font face names. When a font is needed the user agent
2281 iterates over the set of references listed, using the first one it can
2282 successfully activate. Fonts containing invalid data or local font faces
2283 that are not found are ignored and the user agent loads the next font in
2284 the list.
2286 <p>As with other URLs in CSS, the URL may be relative, in which case it is
2287 resolved relative to the location of the style sheet containing the <span
2288 class=index-inst id=font-face0
2289 title="@font-face"><code>@font-face</code></span> rule. In the case of SVG
2290 fonts, the URL points to an element within a document containing SVG font
2291 definitions. If the element reference is omitted, a reference to the first
2292 defined font is implied. Similarly, font container formats that can
2293 contain more than one font must load one and only one of the fonts for a
2294 given <code>@font-face</code> rule. Fragment identifiers are used to
2295 indicate which font to load. If a container format lacks a defined
2296 fragment identifier scheme, implementations should use a simple 1-based
2297 indexing scheme (e.g. "font-collection#1" for the first font,
2298 "font-collection#2" for the second font).
2300 <pre>
2301 src: url(fonts/simple.ttf); /* load simple.ttf relative to stylesheet location */
2302 src: url(/fonts/simple.ttf); /* load simple.ttf from absolute location */
2303 src: url(fonts.svg#simple); /* load SVG font with id 'simple' */
2304 </pre>
2306 <p>External references consist of a URL, followed by an optional hint
2307 describing the format of the font resource referenced by that URL. The
2308 format hint contains a comma-separated list of format strings that denote
2309 well-known font formats. Conformant user agents must skip downloading a
2310 font resource if the format hints indicate only unsupported or unknown
2311 font formats. If no format hints are supplied, the user agent should
2312 download the font resource.
2314 <pre>
2315 /* load WOFF font if possible, otherwise use OpenType font */
2316 @font-face {
2317 font-family: bodytext;
2318 src: url(ideal-sans-serif.woff) format("woff"),
2319 url(basic-sans-serif.ttf) format("opentype");
2320 }
2321 </pre>
2323 <p>Format strings defined by this specification:
2325 <table class=data id=fontformats>
2326 <thead>
2327 <tr>
2328 <th>String
2330 <th>Font Format
2332 <th>Common extensions
2334 <tbody>
2335 <tr>
2336 <th>"woff"
2338 <td><a href="http://www.w3.org/TR/WOFF/">WOFF (Web Open Font Format)</a>
2340 <td>.woff
2342 <tr>
2343 <th>"truetype"
2345 <td><a
2346 href="http://www.microsoft.com/typography/otspec/default.htm">TrueType</a>
2348 <td>.ttf
2350 <tr>
2351 <th>"opentype"
2353 <td><a
2354 href="http://www.microsoft.com/typography/otspec/default.htm">OpenType</a>
2356 <td>.ttf, .otf
2358 <tr>
2359 <th>"embedded-opentype"
2361 <td><a
2362 href="http://www.w3.org/Submission/2008/SUBM-EOT-20080305/">Embedded
2363 OpenType</a>
2365 <td>.eot
2367 <tr>
2368 <th>"svg"
2370 <td><a href="http://www.w3.org/TR/SVG/fonts.html">SVG Font</a>
2372 <td>.svg, .svgz
2373 </table>
2375 <p>Given the overlap in common usage between TrueType and OpenType, the
2376 format hints "truetype" and "opentype" must be considered as synonymous; a
2377 format hint of "opentype" does not imply that the font contains Postscript
2378 CFF style glyph data or that it contains OpenType layout information (see
2379 <a href="#platform-props-to-css">Appendix A</a> for more background on
2380 this).
2382 <p>When authors would prefer to use a locally available copy of a given
2383 font and download it if it's not, <code>local()</code> can be used. The
2384 locally-installed <dfn
2385 id=font-face-name-value><var><font-face-name></var></dfn> argument
2386 to <code>local()</code> is a format-specific string that uniquely
2387 identifies a single font face within a larger family. The syntax for a <a
2388 href="#font-face-name-value"><var><font-face-name></var></a> is a
2389 unique font face name enclosed by "local(" and ")". The name can
2390 optionally be enclosed in quotes. If unquoted, the unquoted font family
2391 name processing conventions apply; the name must be a sequence of
2392 identifiers separated by whitespace which is converted to a string by
2393 joining the identifiers together separated by a single space.
2395 <pre>
2396 /* regular face of Gentium */
2397 @font-face {
2398 font-family: MyGentium;
2399 src: local(Gentium), /* use locally available Gentium */
2400 url(Gentium.ttf); /* otherwise, download it */
2401 }
2402 </pre>
2404 <p>For OpenType and TrueType fonts, this string is used to match only the
2405 Postscript name or the full font name in the name table of locally
2406 available fonts. Which type of name is used varies by platform and font,
2407 so authors should include both of these names to assure proper matching
2408 across platforms. Platform substitutions for a given font name must not be
2409 used.
2411 <pre>
2412 /* bold face of Gentium */
2413 @font-face {
2414 font-family: MyGentium;
2415 src: local(Gentium Bold), /* full font name */
2416 local(Gentium-Bold), /* Postscript name */
2417 url(GentiumBold.ttf); /* otherwise, download it */
2418 font-weight: bold;
2419 }
2420 </pre>
2422 <p>Just as a <code>@font-face</code> rule specifies the characteristics of
2423 a single font within a family, the unique name used with
2424 <code>local()</code> specifies a single font, not an entire font family.
2425 Defined in terms of OpenType font data, the Postscript name is found in
2426 the font's <a
2427 href="http://www.microsoft.com/typography/otspec/name.htm">name table</a>,
2428 in the name record with nameID = 6 (see <a href="#OPENTYPE"
2429 rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> for more details). The
2430 Postscript name is the commonly used key for all fonts on OSX and for
2431 Postscript CFF fonts under Windows. The full font name (nameID = 4) is
2432 used as a unique key for fonts with TrueType glyphs on Windows.
2434 <p>For OpenType fonts with multiple localizations of the full font name,
2435 the US English version is used (language ID = 0x409 for Windows and
2436 language ID = 0 for Macintosh) or the first localization when a US English
2437 full font name is not available (the OpenType specification recommends
2438 that <a href="http://www.microsoft.com/typography/otspec/recom.htm">all
2439 fonts minimally include US English names</a>). User agents that also match
2440 other full font names, e.g. matching the Dutch name when the current
2441 system locale is set to Dutch, are considered non-conformant. This is done
2442 not to prefer English but to avoid matching inconsistencies across font
2443 versions and OS localizations, since font style names (e.g. "Bold") are
2444 frequently localized into many languages and the set of localizations
2445 available varies widely across platform and font version. User agents that
2446 match a concatenation of family name (nameID = 1) with style name (nameID
2447 = 2) are considered non-conformant.
2449 <p>This also allows for referencing faces that belong to larger families
2450 that cannot otherwise be referenced.
2452 <div class=example>
2453 <p>Use a local font or reference an SVG font in another document:</p>
2455 <pre>
2456 @font-face {
2457 font-family: Headline;
2458 src: local(Futura-Medium),
2459 url(fonts.svg#MyGeometricModern) format("svg");
2460 }
2461 </pre>
2463 <p>Create an alias for local Japanese fonts on different platforms:</p>
2465 <pre>
2466 @font-face {
2467 font-family: jpgothic;
2468 src: local(HiraKakuPro-W3), local(Meiryo), local(IPAPGothic);
2469 }
2470 </pre>
2472 <p>Reference a font face that cannot be matched within a larger family:</p>
2474 <pre>
2475 @font-face {
2476 font-family: Hoefler Text Ornaments;
2477 /* has the same font properties as Hoefler Text Regular */
2478 src: local(HoeflerText-Ornaments);
2479 }
2480 </pre>
2482 <p>Since localized fullnames never match, a document with the header style
2483 rules below would always render using the default serif font, regardless
2484 whether a particular system locale parameter is set to Finnish or not:</p>
2486 <pre>
2487 @font-face {
2488 font-family: SectionHeader;
2489 src: local("Arial Lihavoitu"); /* Finnish fullname for Arial Bold, should fail */
2490 font-weight: bold;
2491 }
2493 h2 { font-family: SectionHeader, serif; }
2494 </pre>
2496 <p>A conformant user agent would never load the font ‘<code
2497 class=css>gentium.eot</code>’ in the example below, since it is
2498 included in the first definition of the ‘<a href="#descdef-src"><code
2499 class=property>src</code></a>’ descriptor which is overridden by the
2500 second definition in the same <code>@font-face</code> rule:</p>
2502 <pre>
2503 @font-face {
2504 font-family: MainText;
2505 src: url(gentium.eot); /* for use with older non-conformant user agents */
2506 src: local("Gentium"), url(gentium.ttf); /* Overrides src definition */
2507 }
2508 </pre>
2509 </div>
2511 <h3 id=font-prop-desc><span class=secno>4.4 </span>Font property
2512 descriptors: the <a href="#descdef-font-style">font-style</a>, <a
2513 href="#descdef-font-weight">font-weight</a>, <a
2514 href="#descdef-font-stretch">font-stretch</a> descriptors</h3>
2516 <table class=descdef>
2517 <tbody>
2518 <tr>
2519 <td>Name:
2521 <td><dfn id=descdef-font-style
2522 title="font-style!!descriptor">font-style</dfn>
2524 <tr>
2525 <td>Value:
2527 <td>normal | italic | oblique
2529 <tr>
2530 <td><em>Initial:</em>
2532 <td>normal
2533 </table>
2535 <table class=descdef>
2536 <tbody>
2537 <tr>
2538 <td>Name:
2540 <td><dfn id=descdef-font-weight
2541 title="font-weight!!descriptor">font-weight</dfn>
2543 <tr>
2544 <td>Value:
2546 <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
2548 <tr>
2549 <td><em>Initial:</em>
2551 <td>normal
2552 </table>
2554 <table class=descdef>
2555 <tbody>
2556 <tr>
2557 <td>Name:
2559 <td><dfn id=descdef-font-stretch
2560 title="font-stretch!!descriptor">font-stretch</dfn>
2562 <tr>
2563 <td>Value:
2565 <td>normal | ultra-condensed | extra-condensed | condensed |
2566 semi-condensed | semi-expanded | expanded | extra-expanded |
2567 ultra-expanded
2569 <tr>
2570 <td><em>Initial:</em>
2572 <td>normal
2573 </table>
2575 <p>These descriptors define the characteristics of a font face and are used
2576 in the process of matching styles to specific faces. For a font family
2577 defined with several <code>@font-face</code> rules, user agents can either
2578 download all faces in the family or use these descriptors to selectively
2579 download font faces that match actual styles used in document. The values
2580 for these descriptors are the same as those for the corresponding font
2581 properties except that relative keywords are not allowed, ‘<a
2582 href="#bolder"><code class=property>bolder</code></a>’ and ‘<a
2583 href="#lighter"><code class=property>lighter</code></a>’. If these
2584 descriptors are omitted, initial values are assumed.
2586 <p>The value for these font face style attributes is used in place of the
2587 style implied by the underlying font data. This allows authors to combine
2588 faces in flexible combinations, even in situations where the original font
2589 data was arranged differently. User agents that implement synthetic
2590 bolding and obliquing must only apply synthetic styling in cases where the
2591 font descriptors imply this is needed, rather than based on the style
2592 attributes implied by the font data.
2594 <h3 id=unicode-range-desc><span class=secno>4.5 </span>Character range: the
2595 <a href="#descdef-unicode-range">unicode-range</a> descriptor</h3>
2597 <table class=descdef>
2598 <tbody>
2599 <tr>
2600 <td>Name:
2602 <td><dfn id=descdef-unicode-range>unicode-range</dfn>
2604 <tr>
2605 <td>Value:
2607 <td><a href="#urange-value"><var><urange></var></a> #
2609 <tr>
2610 <td><em>Initial:</em>
2612 <td>U+0-10FFFF
2613 </table>
2615 <p>This descriptor defines the set of Unicode codepoints that may be
2616 supported by the font face for which it is declared. The descriptor value
2617 is a comma-delimited list of Unicode range (<a
2618 href="#urange-value"><var><urange></var></a>) values. The union of
2619 these ranges defines the set of codepoints that serves as a hint for user
2620 agents when deciding whether or not to download a font resource for a
2621 given text run.
2623 <p>Each <dfn id=urange-value><var><urange></var></dfn> value is a <a
2624 href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
2625 title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token made up of a
2626 "U+" or "u+" prefix followed by a codepoint range in one of the three
2627 forms listed below. Ranges that do not fit one of the these forms are
2628 invalid and cause the declaration to be ignored.
2630 <dl>
2631 <dt>single codepoint (e.g. U+416)
2633 <dd>a valid Unicode codepoint, represented as one to six hexadecimal
2634 digits
2636 <dt>interval range (e.g. U+400-4ff)
2638 <dd>represented as two hyphen-separated valid Unicode codepoints
2639 indicating the inclusive start and end codepoints of a range
2641 <dt>wildcard range (e.g. U+4??)
2643 <dd>defined by the set of codepoints implied when trailing ‘<code
2644 class=css>?</code>’ characters signify any hexadeximal digit
2645 </dl>
2647 <p>Individual codepoints are written using hexadecimal values that
2648 correspond to <a href="http://www.unicode.org/charts/">Unicode character
2649 codepoints</a>. Valid Unicode codepoint values vary between 0 and 10FFFF
2650 inclusive. Digit values of codepoints are ASCII case-insensitive. For
2651 interval ranges, the start and end codepoints must be valid Unicode values
2652 and the end codepoint must be greater than or equal to the start
2653 codepoint.
2655 <p>Wildcard ranges specified with ‘?’ that lack an initial digit (e.g.
2656 "U+???") are valid and equivalent to a wildcard range with an initial zero
2657 digit (e.g. "U+0???" = "U+0000-0FFF"). Wildcard ranges that extend beyond
2658 the range of valid Unicode codepoints are invalid. Because of this, the
2659 maximum number of trailing ‘<code class=css>?</code>’ wildcard
2660 characters is five, even though the <a
2661 href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><code
2662 title="UNICODE-RANGE token">UNICODE-RANGE</code></a> token accepts six.
2664 <p>Within the comma-delimited list of Unicode ranges in a ‘<a
2665 href="#descdef-unicode-range"><code
2666 class=property>unicode-range</code></a>’ descriptor declaration, ranges
2667 may overlap. The union of these ranges defines the set of codepoints for
2668 which the corresponding font may be used. User agents must not download or
2669 use the font for codepoints outside this set. User agents may normalize
2670 the list of ranges into a list that is different but represents the same
2671 set of codepoints.
2673 <p>The associated font might not contain glyphs for the entire set of
2674 codepoints defined by the ‘<a href="#descdef-unicode-range"><code
2675 class=property>unicode-range</code></a>’ descriptor. When the font is
2676 used the effective <a href="#character-map"><em>character map</em></a> is
2677 the intersection of the codepoints defined by ‘<a
2678 href="#descdef-unicode-range"><code
2679 class=property>unicode-range</code></a>’ with the font's <a
2680 href="#character-map"><em>character map</em></a>. This allows authors to
2681 define supported ranges in terms of broad ranges without worrying about
2682 the precise codepoint ranges supported by the underlying font.
2684 <h3 id=composite-fonts><span class=secno>4.6 </span>Using character ranges
2685 to define composite fonts</h3>
2687 <p>Multiple <code>@font-face</code> rules with different unicode ranges for
2688 the same family and style descriptor values can be used to create
2689 composite fonts that mix the glyphs from different fonts for different
2690 scripts. This can be used to combine fonts that only contain glyphs for a
2691 single script (e.g. Latin, Greek, Cyrillic) or it can be used by authors
2692 as a way of segmenting a font into fonts for commonly used characters and
2693 less frequently used characters. Since the user agent will only pull down
2694 the fonts it needs this helps reduce page bandwidth.
2696 <p>If the unicode ranges overlap for a set of <code>@font-face</code> rules
2697 with the same family and style descriptor values, the rules are ordered in
2698 the reverse order they were defined; the last rule defined is the first to
2699 be checked for a given character.
2701 <p>Example ranges for specific languages or characters:
2703 <dl>
2704 <dt>unicode-range: U+A5;
2706 <dd>a single code point, the yen/yuan symbol
2708 <dt>unicode-range: U+0-7F;
2710 <dd>code range for basic ASCII characters
2712 <dt>unicode-range: U+590-5ff;
2714 <dd>code range for Hebrew characters
2716 <dt>unicode-range: U+A5, U+4E00-9FFF, U+30??, U+FF00-FF9F;
2718 <dd>code range for Japanese kanji, hiragana and katakana characters plus
2719 yen/yuan symbol
2720 </dl>
2722 <div class=example>
2723 <p>The BBC provides news services in a wide variety of languages, many
2724 that are not well supported across all platforms. Using an
2725 <code>@font-face</code> rule, the BBC could provide a font for any of
2726 these languages, as it already does via a manual font download.</p>
2728 <pre>
2729 @font-face {
2730 font-family: BBCBengali;
2731 src: url(fonts/BBCBengali.ttf) format("opentype");
2732 unicode-range: U+00-FF, U+980-9FF;
2733 }
2734 </pre>
2735 </div>
2737 <div class=example>
2738 <p>Technical documents often require a wide range of symbols. The STIX
2739 Fonts project is one project aimed at providing fonts to support a wide
2740 range of technical typesetting in a standardized way. The example below
2741 shows the use of a font that provides glyphs for many of the mathematical
2742 and technical symbol ranges within Unicode:</p>
2744 <pre>
2745 @font-face {
2746 font-family: STIXGeneral;
2747 src: local(STIXGeneral), url(/stixfonts/STIXGeneral.otf);
2748 unicode-range: U+000-49F, U+2000-27FF, U+2900-2BFF, U+1D400-1D7FF;
2749 }
2750 </pre>
2751 </div>
2753 <div class=example>
2754 <p>This example shows how an author can override the glyphs used for Latin
2755 characters in a Japanese font with glyphs from a different font. The
2756 first rule specifies no range so it defaults to the entire range. The
2757 range specified in the second rule overlaps but takes precedence because
2758 it is defined later.</p>
2760 <pre>
2761 @font-face {
2762 font-family: JapaneseWithGentium;
2763 src: local(MSMincho);
2764 /* no range specified, defaults to entire range */
2765 }
2767 @font-face {
2768 font-family: JapaneseWithGentium;
2769 src: url(../fonts/Gentium.ttf);
2770 unicode-range: U+0-2FF;
2771 }
2772 </pre>
2773 </div>
2775 <div class=example>
2776 <p>Consider a family constructed to optimize bandwidth by separating out
2777 Latin, Japanese and other characters into different font files:</p>
2779 <pre>
2780 /* fallback font - size: 4.5MB */
2781 @font-face {
2782 font-family: DroidSans;
2783 src: url(DroidSansFallback.ttf);
2784 /* no range specified, defaults to entire range */
2785 }
2787 /* Japanese glyphs - size: 1.2MB */
2788 @font-face {
2789 font-family: DroidSans;
2790 src: url(DroidSansJapanese.ttf);
2791 unicode-range: U+3000-9FFF, U+ff??;
2792 }
2794 /* Latin, Greek, Cyrillic along with some
2795 punctuation and symbols - size: 190KB */
2796 @font-face {
2797 font-family: DroidSans;
2798 src: url(DroidSans.ttf);
2799 unicode-range: U+000-5FF, U+1e00-1fff, U+2000-2300;
2800 }
2801 </pre>
2803 <p>For simple Latin text, only the font for Latin characters is
2804 downloaded:</p>
2806 <pre>
2807 body { font-family: DroidSans; }
2809 <p>This is that</p>
2810 </pre>
2812 <p>In this case the user agent first checks the unicode-range for the font
2813 containing Latin characters (DroidSans.ttf). Since all the characters
2814 above are in the range U+0-5FF, the user agent downloads the font and
2815 renders the text with that font.</p>
2817 <p>Next, consider text that makes use of an arrow character (⇨):</p>
2819 <pre>
2820 <p>This &#x21e8; that<p>
2821 </pre>
2823 <p>The user agent again first checks the unicode-range of the font
2824 containing Latin characters. Since U+2000-2300 includes the arrow code
2825 point (U+21E8), the user agent downloads the font. For this character
2826 however the Latin font does not have a matching glyph, so the effective
2827 unicode-range used for font matching excludes this code point. Next, the
2828 user agent evaluates the Japanese font. The unicode-range for the
2829 Japanese font, U+3000-9FFF and U+ff??, does not include U+21E8, so the
2830 user agent does not download the Japanese font. Next the fallback font is
2831 considered. The <code>@font-face</code> rule for the fallback font does
2832 not define unicode-range so its value defaults to the range of all
2833 Unicode code points. The fallback font is downloaded and used to render
2834 the arrow character.</p>
2835 </div>
2837 <h3 id=font-rend-desc><span class=secno>4.7 </span>Font features: the <a
2838 href="#descdef-font-variant">font-variant</a> and <a
2839 href="#descdef-font-feature-settings">font-feature-settings</a>
2840 descriptors</h3>
2842 <table class=descdef>
2843 <tbody>
2844 <tr>
2845 <td>Name:
2847 <td><dfn id=descdef-font-variant
2848 title="font-variant!!descriptor">font-variant</dfn>
2850 <tr>
2851 <td>Value:
2853 <td><a href="#font-variant-normal-value"
2854 title="normal!!font-variant">normal</a> | <a
2855 href="#font-variant-none-value" title="none!!font-variant">none</a> | [
2856 <a href="#common-lig-values"><var><common-lig-values></var></a>
2857 || <a
2858 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
2859 || <a
2860 href="#historical-lig-values"><var><historical-lig-values></var></a>
2861 || <a
2862 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
2863 || <a href="#stylistic"><var
2864 title=stylistic>stylistic(<feature-value-name>)</var></a> || <a
2865 href="#historical-forms"><var>historical-forms</var></a> || <a
2866 href="#styleset"><var
2867 title=styleset>styleset(<feature-value-name> #)</var></a> || <a
2868 href="#character-variant"><var
2869 title=character-variant>character-variant(<feature-value-name>
2870 #)</var></a> || <a href="#swash"><var
2871 title=swash>swash(<feature-value-name>)</var></a> || <a
2872 href="#ornaments"><var
2873 title=ornaments>ornaments(<feature-value-name>)</var></a> || <a
2874 href="#annotation"><var
2875 title=annotation>annotation(<feature-value-name>)</var></a> || [
2876 <a href="#small-caps"><i>small-caps</i></a> | <a
2877 href="#all-small-caps"><i>all-small-caps</i></a> | <a
2878 href="#petite-caps"><i>petite-caps</i></a> | <a
2879 href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
2880 href="#unicase"><i>unicase</i></a> | <a
2881 href="#titling-caps"><i>titling-caps</i></a> ] || <a
2882 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
2883 || <a
2884 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
2885 || <a
2886 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
2887 || <a href="#ordinal"><i>ordinal</i></a> || <a
2888 href="#slashed-zero"><i>slashed-zero</i></a> || <a
2889 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
2890 || <a
2891 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
2892 || <a href="#ruby"><i>ruby</i></a> ]
2894 <tr>
2895 <td><em>Initial:</em>
2897 <td>normal
2898 </table>
2900 <table class=descdef>
2901 <tbody>
2902 <tr>
2903 <td>Name:
2905 <td><dfn id=descdef-font-feature-settings
2906 title="font-feature-settings!!descriptor">font-feature-settings</dfn>
2908 <tr>
2909 <td>Value:
2911 <td><a href="#font-feature-settings-normal-value"
2912 title="normal!!font-feature-settings">normal</a> | <a
2913 href="#feature-tag-value"><var><feature-tag-value></var></a> #
2915 <tr>
2916 <td><em>Initial:</em>
2918 <td>normal
2919 </table>
2921 <p>These descriptors define initial settings that apply when the font
2922 defined by an <code>@font-face</code> rule is rendered. They do not affect
2923 font selection. Values are identical to those defined for the
2924 corresponding <a href="#propdef-font-variant"
2925 title="font-variant!!property">‘<code
2926 class=property>font-variant</code>’</a> and <span
2927 title="font-feature-settings!!property">‘<a
2928 href="#propdef-font-feature-settings"><code
2929 class=property>font-feature-settings</code></a>’</span> properties
2930 defined below except that the value ‘<code
2931 class=property>inherit</code>’ is omitted. When multiple font feature
2932 descriptors or properties are used, the cumulative effect on text
2933 rendering is detailed in the section <a
2934 href="#font-feature-resolution">Font Feature Resolution</a> below. In
2935 cases where specific values define synthesized fallback for certain <a
2936 href="#propdef-font-variant" title="font-variant!!property">‘<code
2937 class=property>font-variant</code>’</a> subproperties, the same
2938 synthesized fallback applies when used within those values are used with
2939 the <a href="#descdef-font-style" title="font-style!!descriptor">‘<code
2940 class=property>font-variant</code>’</a> descriptor.
2942 <h3 id=font-face-loading><span class=secno>4.8 </span>Font loading
2943 guidelines</h3>
2945 <p>The <code>@font-face</code> rule is designed to allow lazy loading of
2946 font resources that are only downloaded when used within a document. A
2947 stylesheet can include <code>@font-face</code> rules for a library of
2948 fonts of which only a select set are used; user agents must only download
2949 those fonts that are referred to within the style rules applicable to a
2950 given page. User agents that download all fonts defined in
2951 <code>@font-face</code> rules without considering whether those fonts are
2952 in fact used within a page are considered non-conformant. In cases where a
2953 font might be downloaded in character fallback cases, user agents may
2954 download a font if it's listed in a font list but is not actually used for
2955 a given text run.
2957 <pre>
2958 @font-face {
2959 font-family: GeometricModern;
2960 src: url(font.ttf);
2961 }
2963 p {
2964 /* font will be downloaded for pages with p elements */
2965 font-family: GeometricModern, sans-serif;
2966 }
2968 h2 {
2969 /* font may be downloaded for pages with h2 elements, even if Futura is available locally */
2970 font-family: Futura, GeometricModern, sans-serif;
2971 }
2972 </pre>
2974 <p>In cases where textual content is loaded before downloadable fonts are
2975 available, user agents may render text as it would be rendered if
2976 downloadable font resources are not available or they may render text
2977 transparently with fallback fonts to avoid a flash of text using a
2978 fallback font. In cases where the font download fails user agents must
2979 display text, simply leaving transparent text is considered non-conformant
2980 behavior. Authors are advised to use fallback fonts in their font lists
2981 that closely match the vertical metrics of the downloadable fonts to avoid
2982 large page reflows where possible.
2984 <h3 id=same-origin-restriction><span class=secno>4.9 </span>Same-origin
2985 restriction for fonts</h3>
2987 <h4 id=default-same-origin-restriction><span class=secno>4.9.1
2988 </span>Default same-origin restriction</h4>
2989 <!-- TPAC 2011 Resolution to require same-origin restriction for loading fonts:
2990 http://lists.w3.org/Archives/Public/www-style/2011Nov/0711.html
2991 http://www.w3.org/2011/10/31-webapps-minutes.html#item02
2992 -->
2994 <p>User agents must implement a same-origin restriction when loading fonts
2995 via the <code>@font-face</code> mechanism. This restriction limits the
2996 loading of fonts for a given document to fonts loaded from the same
2997 origin. Fonts can only be loaded via the same host, port, and method
2998 combination as the containing document, using the <a
2999 href="http://www.w3.org/TR/html5/browsers.html#origin">origin matching
3000 algorithm</a> described in the <a href="#HTML5"
3001 rel=biblioentry>[HTML5]<!--{{!HTML5}}--></a> specification. The origin of
3002 the stylesheet containing <code>@font-face</code> rules is not used when
3003 deciding whether a font is same origin or not, only the origin of the
3004 containing document is used. The restriction applies to all font types.
3006 <p>Given a document located at http://example.com/page.html, fonts defined
3007 with ‘<a href="#descdef-src"><code class=property>src</code></a>’
3008 definitions considered cross origin must not be loaded:
3010 <pre>
3011 /* same origin (i.e. domain, protocol, port match document) */
3012 src: url(fonts/simple.ttf);
3013 src: url(//fonts/simple.ttf);
3015 /* cross origin, different protocol */
3016 src: url(https://example.com/fonts/simple.ttf);
3018 /* cross origin, different domain */
3019 src: url(http://another.example.com/fonts/simple.ttf);
3020 </pre>
3022 <h4 id=allowing-cross-origin-font-loading><span class=secno>4.9.2
3023 </span>Allowing cross-origin font loading</h4>
3025 <p>User agents must also implement the ability to relax this restriction
3026 using cross-site origin controls <a href="#CORS"
3027 rel=biblioentry>[CORS]<!--{{!CORS}}--></a> for fonts loaded via HTTP.
3028 Sites can explicitly allow cross-site downloading of font data using the
3029 <code>Access-Control-Allow-Origin</code> HTTP header. For other protocols,
3030 no explicit relaxation mechanism is defined or required.
3032 <p>For font loads over HTTP, cross-origin requests must be made with the
3033 following parameter settings which are used in conjunction with the <a
3034 href="http://www.w3.org/TR/cors/#cross-origin-request-0"> <em>cross-origin
3035 request algorithm</em></a> <a href="#CORS"
3036 rel=biblioentry>[CORS]<!--{{!CORS}}--></a>:
3038 <ul>
3039 <li><em>request URL</em> — the URL of the font resource in the <a
3040 href="#descdef-src"><code>src</code></a> descriptor
3042 <li><em>request method</em> — GET
3044 <li><em>author request headers</em> — none
3046 <li><em>request entity body</em> — empty
3048 <li><em>source origin</em> — the origin of the page which linked to the
3049 stylesheet
3051 <li><em>manual redirect flag</em> — false
3053 <li><em>omit credentials flag</em> — true
3055 <li><em>force preflight flag</em> — false
3056 </ul>
3058 <h2 id=font-matching-algorithm><span class=secno>5 </span>Font Matching
3059 Algorithm</h2>
3061 <p>The algorithm below describes how fonts are associated with individual
3062 runs of text. For each character in the run a font family is chosen and a
3063 particular font face is selected containing a glyph for that character.
3065 <h3 id=font-family-casing><span class=secno>5.1 </span>Case sensitivity of
3066 font family names</h3>
3068 <p>As part of the font matching algorithm outlined below, user agents must
3069 match font family names used in style rules with actual font family names
3070 contained in fonts available in a given environment or defined via
3071 <code>@font-face</code> rules. User agents must match these names case
3072 insensitively, using the "Default Caseless Matching" algorithm outlined in
3073 the Unicode specification <a href="#UNICODE6"
3074 rel=biblioentry>[UNICODE6]<!--{{!UNICODE6}}--></a>. This algorithm is
3075 detailed in section 3.13 entitled "Default Case Algorithms". Specifically,
3076 the algorithm must be applied without normalizing the strings involved and
3077 without applying any language-specific tailorings. The case folding method
3078 specified by this algorithm uses the case mappings with status field
3079 ‘<code class=property>C</code>’ or ‘<code class=property>F</code>’
3080 in the CaseFolding.txt file of the Unicode Character Database.
3082 <p class=note> Implementors should take care to verify that a given
3083 caseless string comparison implementation uses this precise algorithm and
3084 not assume that a given platform string matching routine follows it, as
3085 many of these have locale-specific behavior or use some level of string
3086 normalization.
3088 <p class=note> For authors this means that font family names are matched
3089 case insensitively, whether those names exist in a platform font or in the
3090 <code>@font-face</code> rules contained in a stylesheet. Authors should
3091 take care to ensure that names use a character sequence consistent with
3092 the actual font family name, particularly when using combining characters
3093 such as diacritical marks. For example, a family name that contains an
3094 uppercase A (U+0041) followed by a combining ring (U+030A) will
3095 <strong>not</strong> match a name that looks identical but which uses the
3096 precomposed lowercase a-ring character (U+00E5) instead of the combining
3097 sequence.
3099 <h3 id=font-style-matching><span class=secno>5.2 </span>Matching font
3100 styles</h3>
3102 <p>The procedure for choosing fonts consists of iterating over the font
3103 families determined by the font-family property, selecting a font face
3104 with the appropriate style based on other font properties and then
3105 determining whether a glyph exists for a given character. This is done
3106 using the <dfn id=character-map>character map</dfn> of the font, data
3107 which maps characters to the default glyph for that character. Codepoint
3108 sequences consisting of a base character followed by a sequence of
3109 combining characters are treated slightly differently, see the section on
3110 <a href="#cluster-matching">cluster matching</a> below.
3112 <p>For this procedure, the <dfn id=default-face>default face</dfn> for a
3113 given font family is defined to be the face that would be selected if all
3114 font style properties were set to their initial value.
3116 <ol id=fontmatchingalg>
3117 <li>Using the computed font property values for a given element, the user
3118 agent starts with the first family name in the fontlist specified by the
3119 <a href="#propdef-font-family" title="font-family!!property">‘<code
3120 class=property>font-family</code>’</a> property.
3122 <li>If the family name is unquoted and is a generic family name, the user
3123 agent looks up the appropriate font family name to be used. User agents
3124 may choose the generic font family to use based on the language of the
3125 containing element or the Unicode range of the character.
3127 <li>For other family names, the user agent attempts to find the family
3128 name among fonts defined via <code>@font-face</code> rules and then among
3129 available system fonts, matching names with a case-insensitive comparison
3130 as outlined <a href="#font-family-casing">in the section above</a>. On
3131 systems containing fonts with multiple localized font family names, user
3132 agents must match any of these names independent of the underlying system
3133 locale or platform API used. If the font resources defined for a given
3134 face in an @font-face rule are either not available or contain invalid
3135 font data, then the face should be treated as not present in the family.
3136 If no faces are present for a family defined via @font-face rules, the
3137 family should be treated as missing; matching a platform font with the
3138 same name must not occur in this case.
3140 <li>If a font family match occurs, the user agent assembles the set of
3141 font faces in that family and then narrows the set to a single face using
3142 other font properties in the order given below:
3143 <ol id=fontstylematchingalg>
3144 <li><a href="#propdef-font-stretch"
3145 title="font-stretch!!property">‘<code
3146 class=property>font-stretch</code>’</a> is tried first. If the
3147 matching set contains faces with width values matching the <a
3148 href="#propdef-font-stretch" title="font-stretch!!property">‘<code
3149 class=property>font-stretch</code>’</a> value, faces with other width
3150 values are removed from the matching set. If there is no face that
3151 exactly matches the width value the nearest width is used instead. If
3152 the value of <a href="#propdef-font-stretch"
3153 title="font-stretch!!property">‘<code
3154 class=property>font-stretch</code>’</a> is ‘<code
3155 class=property>normal</code>’ or one of the condensed values,
3156 narrower width values are checked first, then wider values. If the
3157 value of <a href="#propdef-font-stretch"
3158 title="font-stretch!!property">‘<code
3159 class=property>font-stretch</code>’</a> is one of the expanded
3160 values, wider values are checked first, followed by narrower values.
3161 Once the closest matching width has been determined by this process,
3162 faces with other widths are removed from the matching set.
3164 <li><a href="#propdef-font-style" title="font-style!!property">‘<code
3165 class=property>font-style</code>’</a> is tried next. If the value of
3166 <a href="#propdef-font-style" title="font-style!!property">‘<code
3167 class=property>font-style</code>’</a> is ‘<a href="#italic"><code
3168 class=property>italic</code></a>’, italic faces are checked first,
3169 then oblique, then normal faces. If the value is ‘<a
3170 href="#oblique"><code class=property>oblique</code></a>’, oblique
3171 faces are checked first, then italic faces and then normal faces. If
3172 the value is ‘<code class=property>normal</code>’, normal faces are
3173 checked first, then oblique faces, then italic faces. Faces with other
3174 style values are excluded from the matching set. User agents are
3175 permitted to distinguish between italic and oblique faces within
3176 platform font families but this is not required, they may treat all
3177 italic or oblique faces as italic faces. However, within font families
3178 defined via <code>@font-face</code> rules, italic and oblique faces
3179 must be distinguished using the value of the <a
3180 href="#descdef-font-style" title="font-style!!descriptor">‘<code
3181 class=property>font-style</code>’</a> descriptor.
3183 <li><a href="#propdef-font-weight"
3184 title="font-weight!!property">‘<code
3185 class=property>font-weight</code>’</a> is matched next, it will
3186 always reduce the matching set to a single font face. If bolder/lighter
3187 relative weights are used, the effective weight is calculated based on
3188 the inherited weight value, as described in the definition of the <a
3189 href="#propdef-font-weight" title="font-weight!!property">‘<code
3190 class=property>font-weight</code>’</a> property. Given the desired
3191 weight and the weights of faces in the matching set after the steps
3192 above, if the desired weight is available that face matches. Otherwise,
3193 a weight is chosen using the rules below:
3194 <ul>
3195 <li>If the desired weight is less than 400, weights below the desired
3196 weight are checked in descending order followed by weights above the
3197 desired weight in ascending order until a match is found.
3199 <li>If the desired weight is greater than 500, weights above the
3200 desired weight are checked in ascending order followed by weights
3201 below the desired weight in descending order until a match is found.
3203 <li>If the desired weight is 400, 500 is checked first and then the
3204 rule for desired weights less than 400 is used.
3206 <li>If the desired weight is 500, 400 is checked first and then the
3207 rule for desired weights less than 400 is used.
3208 </ul>
3210 <li><span class=property>‘<a href="#propdef-font-size"><code
3211 class=property>font-size</code></a>’</span> must be matched within a
3212 UA-dependent margin of tolerance. (Typically, sizes for scalable fonts
3213 are rounded to the nearest whole pixel, while the tolerance for
3214 bitmapped fonts could be as large as 20%.) Further computations, e.g.,
3215 by ‘<code class=property>em</code>’ values in other properties, are
3216 based on the <span class=property>‘<a href="#propdef-font-size"><code
3217 class=property>font-size</code></a>’</span> value that is used, not
3218 the one that is specified.
3219 </ol>
3221 <li>
3222 <p>If no matching face exists or the matched face does not contain a
3223 glyph for the character to be rendered, the next family name is selected
3224 and the previous two steps repeated. Glyphs from other faces in the
3225 family are not considered. The only exception is that user agents may
3226 optionally substitute a synthetic version of the <a
3227 href="#default-face"><em>default face</em></a> if that face supports a
3228 given glyph (e.g. a synthetic italic version of the regular face may be
3229 used if the italic face doesn't support glyphs for Arabic).</p>
3230 <!-- resolution on the above: http://lists.w3.org/Archives/Public/www-style/2012Nov/0292.html -->
3232 <p>If the matched font is defined via an <code>@font-face</code> rule and
3233 needs to be downloaded, the font resource is downloaded. While the
3234 download occurs, the user agent can either wait until the font is
3235 downloaded or render once with substituted font metrics and render again
3236 once the font is downloaded.</p>
3238 <li>If there are no more font families to be evaluated and no matching
3239 face has been found, then the user agent performs a <em>system font
3240 fallback</em> procedure to find the best match for the character to be
3241 rendered. The result of this procedure may vary across user agents.
3243 <li>If a particular character cannot be displayed using any font, the user
3244 agent should indicate by some means that a character is not being
3245 displayed, displaying either a symbolic representation of the missing
3246 glyph (e.g. using a <a
3247 href="http://en.wikipedia.org/wiki/Last_resort_font">Last Resort
3248 Font</a>) or using the missing character glyph from a default font.
3249 </ol>
3251 <h3 id=cluster-matching><span class=secno>5.3 </span>Cluster matching</h3>
3253 <p>When text contains characters such as combining diacritics, ideally the
3254 base character should be rendered using the same font as the diacritic,
3255 this assures proper placement of the diacritic. For this reason, the font
3256 matching algorithm for clusters is more specialized than the general case
3257 of matching a single character by itself. For sequences containing
3258 variation selectors, which indicate the precise glyph to be used for a
3259 given character, user agents always attempt system font fallback to find
3260 the appropriate glyph before using the default glyph of the base
3261 character.
3263 <p>A font is considered to <em>support</em> a given character if (1) the
3264 character is contained in the font's <a
3265 href="#character-map"><em>character map</em></a> and (2) if required by
3266 the containing script, shaping information is available for that
3267 character. Some legacy fonts may include a given character in the <a
3268 href="#character-map"><em>character map</em></a> but lack the shaping
3269 information (e.g. <a
3270 href="http://www.microsoft.com/typography/otspec/ttochap1.htm">OpenType
3271 layout tables</a> or <a
3272 href="http://scripts.sil.org/cms/scripts/page.php?site_id=projects&item_id=graphite_techAbout">Graphite
3273 tables</a>) necessary for correctly rendering text runs containing that
3274 character.
3276 <p>A sequence of codepoints containing combining diacritics or other
3277 modifiers is termed a grapheme cluster (see <a href="#CSS3TEXT"
3278 rel=biblioentry>[CSS3TEXT]<!--{{CSS3TEXT}}--></a> for a more complete
3279 description). For a given cluster containing a base character, <em>b</em>
3280 and a sequence of combining characters <em>c1, c2…</em>, the entire
3281 cluster is matched using these steps:
3283 <ol>
3284 <li>For each family in the font list, a face is chosen using the style
3285 selection rules defined in the previous section.
3286 <ol>
3287 <li>If all characters in the sequence <em>b + c1 + c2 …</em> are
3288 completely supported by the font, select this font for the sequence.
3290 <li>If a sequence of multiple codepoints is canonically equivalent to a
3291 single character and the font supports that character, select this font
3292 for the sequence.
3293 </ol>
3295 <li>If no font was found in the font list in step 1:
3296 <ol>
3297 <li>If <em>c1</em> is a variation selector, system fallback must be used
3298 to find a font that supports the full sequence of <em>b + c1</em>. If
3299 no font on the system supports the full sequence, match the single
3300 character <em>b</em> using the normal procedure for matching single
3301 characters and ignore the variation selector. Note: a sequence with
3302 more than one variation selector is treated as an encoding error and
3303 the trailing selectors are ignored.
3305 <li>Otherwise, the user agent may optionally use system font fallback to
3306 match a font that supports the entire cluster.
3307 </ol>
3309 <li>If no font is found in step 2, use the matching sequence from step 1
3310 to determine the longest sequence that is completely matched by a font in
3311 the font list and attempt to match the remaining combining characters
3312 separately using the rules for single characters.
3313 </ol>
3315 <h3 id=char-handling-issues><span class=secno>5.4 </span>Character handling
3316 issues</h3>
3318 <p>The procedure above is always performed on text runs containing Unicode
3319 characters, documents using legacy encodings are assumed to have been
3320 transcoded before matching fonts. For fonts containing <a
3321 href="#character-map"><em title="character map">character maps</em></a>
3322 for both legacy encodings and Unicode, the contents of the legacy encoding
3323 <a href="#character-map"><em>character map</em></a> must have no effect on
3324 the results of the font matching process.
3326 <p>The font matching process does not assume that text runs are in either
3327 normalized or denormalized form (see <a href="#CHARMOD-NORM"
3328 rel=biblioentry>[CHARMOD-NORM]<!--{{CHARMOD-NORM}}--></a> for more
3329 details). Layout engines often convert base character plus combining
3330 character sequences into precomposed characters if they exist. The font
3331 matching algorithm outlined here supports both ways and fonts can
3332 generally support either but variations can occur. Authors should always
3333 tailor their choice of fonts to their content, including whether that
3334 content contains normalized or denormalized character streams.
3336 <p>If a given character is a Private-Use Area Unicode codepoint and none of
3337 the fonts in the fontlist contain a glyph for that codepoint, user agents
3338 must display some form of missing glyph symbol for that character rather
3339 than attempting system font fallback for that codepoint. When matching the
3340 replacement character U+FFFD, user agents may skip the font matching
3341 process and immediately display some form of missing glyph symbol, they
3342 are not required to display the glyph from the font that would be selected
3343 by the font matching process.
3345 <p>In general, the fonts for a given family will all have the same or
3346 similar <a href="#character-map"><em title="character map">character
3347 maps</em></a>. The process outlined here is designed to handle even font
3348 families containing faces with widely variant <a href="#character-map"><em
3349 title="character map">character maps</em></a>. However, authors are
3350 cautioned that the use of such families can lead to unexpected results.
3352 <p>Optimizations of this process are allowed provided that an
3353 implementation behaves as if the algorithm had been followed exactly.
3354 Matching occurs in a well-defined order to insure that the results are as
3355 consistent as possible across user agents, given an identical set of
3356 available fonts and rendering technology.
3358 <h3 id=font-matching-changes><span class=secno>5.5 </span>Font matching
3359 changes since CSS 2.1</h3>
3361 <p>The algorithm above is different from CSS 2.1 in a number of key places.
3362 These changes were made to better reflect actual font matching behavior
3363 across user agent implementations.
3365 <p>Differences compared to the font matching algorithm in CSS 2.1:
3367 <ul>
3368 <li>The algorithm includes font-stretch matching.
3370 <li>All possible font-style matching scenarios are delineated.
3372 <li>Small-caps fonts are not matched as part of the font matching process,
3373 they are now handled via font features.
3375 <li>Unicode variation selector matching is required.
3377 <li>Cluster sequences are matched as a unit.
3378 </ul>
3380 <h3 id=font-matching-examples><span class=secno>5.6 </span>Font matching
3381 examples</h3>
3383 <div class=example>
3384 <p>It's useful to note that the CSS selector syntax may be used to create
3385 language-sensitive typography. For example, some Chinese and Japanese
3386 characters are unified to have the same Unicode code point, although the
3387 abstract glyphs are not the same in the two languages.
3389 <pre>*:lang(ja-jp) { font: 900 14pt/16pt "Heisei Mincho W9", serif; }
3390 *:lang(zh-tw) { font: 800 14pt/16.5pt "Li Sung", serif; }
3391 </pre>
3393 <p>This selects any element that has the given language - Japanese or
3394 Traditional Chinese - and uses the appropriate font.
3395 </div>
3397 <h2 id=font-rend-props><span class=secno>6 </span>Font Feature Properties</h2>
3399 <p>Modern font technologies support a variety of advanced typographic and
3400 language-specific font features. Using these features, a single font can
3401 provide glyphs for a wide range of ligatures, contextual and stylistic
3402 alternates, tabular and old-style figures, small capitals, automatic
3403 fractions, swashes, and alternates specific to a given language. To allow
3404 authors control over these font capabilities, the font-variant property
3405 has been expanded for CSS3, it now functions as a shorthand for a set of
3406 properties that provide control over stylistic font features.
3408 <h3 id=glyph-selection-positioning><span class=secno>6.1 </span>Glyph
3409 selection and positioning</h3>
3411 <p>Simple fonts used for displaying Latin text use a very basic processing
3412 model, fonts contain a <a href="#character-map"><em>character map</em></a>
3413 which maps a given character to a glyph for that character. Glyphs for
3414 subsequent characters are simply placed next in line along a run of text.
3415 Font formats such as OpenType and AAT (Apple Advanced Typography) use a
3416 richer processing model, the glyph for a given character can be chosen and
3417 positioned not just based on a single character, but also based on
3418 surrounding characters along with the language, script, and features
3419 enabled for the text. Font features may be required for specific scripts,
3420 or recommended as enabled by default or they may be stylistic features
3421 meant to be used under author control.
3423 <p>For a good visual overview of these features, see the <a
3424 href="#OPENTYPE-FONT-GUIDE"
3425 rel=biblioentry>[OPENTYPE-FONT-GUIDE]<!--{{OPENTYPE-FONT-GUIDE}}--></a>.
3426 For a detailed description of glyph processing for OpenType fonts, see <a
3427 href="#WINDOWS-GLYPH-PROC"
3428 rel=biblioentry>[WINDOWS-GLYPH-PROC]<!--{{WINDOWS-GLYPH-PROC}}--></a>.
3430 <p>Stylistic font features can be classified into two broad categories,
3431 ones that affect the harmonization of glyph shapes with the surrounding
3432 context, such as kerning and ligature features, and those such as the
3433 small-caps, subscript/superscript and alternate features that affect shape
3434 selection.
3436 <p>The subproperties of font-variant listed below are used to control these
3437 stylistic font features; they do not control features that are required
3438 for displaying certain scripts, such as the OpenType features used when
3439 displaying Arabic or Indic language text. They affect glyph selection and
3440 positioning, they do not affect font selection as described in the font
3441 matching section (except in cases required for compatibility with CSS
3442 2.1).
3444 <p>To assure consistent behavior across user agents, the equivalent
3445 OpenType property settings are listed for individual properties and must
3446 be considered normative. When using other font formats these should be
3447 used as a guideline to map CSS font feature property values to specific
3448 font features.
3450 <h3 id=language-specific-support><span class=secno>6.2
3451 </span>Language-specific display</h3>
3453 <p>OpenType also supports language-specific glyph selection and
3454 positioning, so that text can be displayed correctly in cases where the
3455 language dictates a specific display behavior. Languages often share a
3456 common script but the shape of certain letters may vary across those
3457 languages, such as the variations in certain Cyrillic letters used in
3458 Russian and Bulgarian text. In Latin text, it's common to render "fi" with
3459 an explicit fi-ligature that lacks a dot on the "i". However, in languages
3460 such as Turkish which uses both a dotted-i and a dotless-i, it's important
3461 to not use this ligature or use a specialized version that contains a dot
3462 over the "i". The example below shows language-specific variations based
3463 on stylistic traditions found in Spanish, Italian and French orthography:
3465 <div class=featex><img alt="language specific forms, spanish"
3466 src=locl-1.png></div>
3468 <div class=featex><img alt="language specific forms, italian"
3469 src=locl-2.png></div>
3471 <div class=featex><img alt="language specific forms, french"
3472 src=locl-3.png></div>
3474 <p>If the content language of the element is known, according to the rules
3475 of the <a
3476 href="http://www.w3.org/TR/CSS21/conform.html#doclanguage">document
3477 language</a>, user agents are required to infer the OpenType language
3478 system from the content language and use that when selecting and
3479 positioning glyphs using an OpenType font.
3481 <p>For OpenType fonts, in some cases it may be necessary to explicitly
3482 declare the OpenType language to be used, for example when displaying text
3483 in a given language that uses the typographic conventions of another
3484 language or when the font does not explicitly support a given language but
3485 supports a language that shares common typographic conventions. The ‘<a
3486 href="#propdef-font-language-override"><code
3487 class=property>font-language-override</code></a>’ property is used for
3488 this purpose.</p>
3489 <!-- prop: font-kerning -->
3491 <h3 id=font-kerning-prop><span class=secno>6.3 </span>Kerning: the <a
3492 href="#propdef-font-kerning">font-kerning</a> property</h3>
3494 <table class=propdef id=namefont-kerningvalueauto-normal-noneini>
3495 <tbody>
3496 <tr>
3497 <td>Name:
3499 <td><dfn id=propdef-font-kerning>font-kerning</dfn>
3501 <tr>
3502 <td>Value:
3504 <td><a href="#font-kerning-auto-value"
3505 title="auto!!font-kerning">auto</a> | <a
3506 href="#font-kerning-normal-value"
3507 title="normal!!font-kerning">normal</a> | <a
3508 href="#font-kerning-none-value" title="none!!font-kerning">none</a>
3510 <tr>
3511 <td>Initial:
3513 <td>auto
3515 <tr>
3516 <td>Applies to:
3518 <td>all elements
3520 <tr>
3521 <td>Inherited:
3523 <td>yes
3525 <tr>
3526 <td>Percentages:
3528 <td>N/A
3530 <tr>
3531 <td>Media:
3533 <td>visual
3535 <tr>
3536 <td>Computed value:
3538 <td>as specified
3540 <tr>
3541 <td>Animatable:
3543 <td>no
3544 </table>
3546 <p>Kerning is the contextual adjustment of inter-glyph spacing. This
3547 property controls metric kerning, kerning that utilizes adjustment data
3548 contained in the font.
3550 <dl>
3551 <dt><dfn id=font-kerning-auto-value title="auto!!font-kerning">auto</dfn>
3553 <dd>Specifies that kerning is applied at the discretion of the user agent
3555 <dt><dfn id=font-kerning-normal-value
3556 title="normal!!font-kerning">normal</dfn>
3558 <dd>Specifies that kerning is applied
3560 <dt><dfn id=font-kerning-none-value title="none!!font-kerning">none</dfn>
3562 <dd>Specifies that kerning is not applied
3563 </dl>
3565 <p>For fonts that do not include kerning data this property will have no
3566 visible effect. When rendering with OpenType fonts, the <a
3567 href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>
3568 specification suggests that kerning be enabled by default. When kerning is
3569 enabled, the OpenType <span class=tag>kern</span> feature is enabled (for
3570 vertical text runs the <span class=tag>vkrn</span> feature is enabled
3571 instead). User agents must also support fonts that only support kerning
3572 via data contained in a <span class=tag>kern</span> font table, as
3573 detailed in the OpenType specification. If the ‘<code
3574 class=property>letter-spacing</code>’ property is defined, kerning
3575 adjustments are considered part of the default spacing and letter spacing
3576 adjustments are made after kerning has been applied.
3578 <p>When set to ‘<code class=property>auto</code>’, user agents can
3579 determine whether to apply kerning or not based on a number of factors:
3580 text size, script, or other factors that influence text processing speed.
3581 Authors who want proper kerning should use ‘<code
3582 class=property>normal</code>’ to explicitly enable kerning. Likewise,
3583 some authors may prefer to disable kerning in situations where performance
3584 is more important than precise appearance. However, in well-designed
3585 modern implementations the use of kerning generally does not have a large
3586 impact on text rendering speed.</p>
3587 <!-- prop: font-variant-ligatures -->
3589 <h3 id=font-variant-ligatures-prop><span class=secno>6.4 </span>Ligatures:
3590 the <a href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
3591 property</h3>
3593 <table class=propdef id=namefont-variant-ligaturesvaluenormal-no>
3594 <tbody>
3595 <tr>
3596 <td>Name:
3598 <td><dfn id=propdef-font-variant-ligatures>font-variant-ligatures</dfn>
3600 <tr>
3601 <td>Value:
3603 <td><a href="#font-variant-ligatures-normal-value"
3604 title="normal!!font-variant-ligatures">normal</a> | <a
3605 href="#font-variant-ligatures-none-value"
3606 title="none!!font-variant-ligatures">none</a> | [ <a
3607 href="#common-lig-values"><var><common-lig-values></var></a> ||
3608 <a
3609 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
3610 || <a
3611 href="#historical-lig-values"><var><historical-lig-values></var></a>
3612 || <a
3613 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
3614 ]
3616 <tr>
3617 <td>Initial:
3619 <td>normal
3621 <tr>
3622 <td>Applies to:
3624 <td>all elements
3626 <tr>
3627 <td>Inherited:
3629 <td>yes
3631 <tr>
3632 <td>Percentages:
3634 <td>N/A
3636 <tr>
3637 <td>Media:
3639 <td>visual
3641 <tr>
3642 <td>Computed value:
3644 <td>as specified
3646 <tr>
3647 <td>Animatable:
3649 <td>no
3650 </table>
3652 <p>Ligatures and contextual forms are ways of combining glyphs to produce
3653 more harmonized forms.
3655 <pre
3656 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>
3658 <pre
3659 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>
3661 <pre
3662 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>
3664 <pre
3665 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>
3667 <p>Individual values have the following meanings:
3669 <dl>
3670 <dt><dfn id=font-variant-ligatures-normal-value
3671 title="normal!!font-variant-ligatures">normal</dfn>
3673 <dd>A value of ‘<code class=property>normal</code>’ specifies that
3674 common default features are enabled, <a
3675 href="#font-feature-resolution">as described in detail in the next
3676 section</a>. For OpenType fonts, common ligatures and contextual forms
3677 are on by default, discretionary and historical ligatures are not.
3679 <dt><dfn id=font-variant-ligatures-none-value
3680 title="none!!font-variant-ligatures">none</dfn>
3682 <dd>Specifies that all types of ligatures and contextual forms covered by
3683 this property are explicitly disabled. In situations where ligatures are
3684 not considered necessary, this may improve the speed of text rendering.
3686 <dt><dfn id=common-ligatures>common-ligatures</dfn>
3688 <dd>Enables display of common ligatures (OpenType features: <span
3689 class=tag>liga, clig</span>). For OpenType fonts, common ligatures are
3690 enabled by default.
3691 </dl>
3693 <div class=featex><img alt="common ligature example" src=liga.png></div>
3695 <dl>
3696 <dt><dfn id=no-common-ligatures>no-common-ligatures</dfn>
3698 <dd>Disables display of common ligatures (OpenType features: <span
3699 class=tag>liga, clig</span>).
3701 <dt><dfn id=discretionary-ligatures>discretionary-ligatures</dfn>
3703 <dd>Enables display of discretionary ligatures (OpenType feature: <span
3704 class=tag>dlig</span>). Which ligatures are discretionary or optional is
3705 decided by the type designer, so authors will need to refer to the
3706 documentation of a given font to understand which ligatures are
3707 considered discretionary.
3708 </dl>
3710 <div class=featex><img alt="discretionary ligature example" src=dlig.png></div>
3712 <dl>
3713 <dt><dfn id=no-discretionary-ligatures>no-discretionary-ligatures</dfn>
3715 <dd>Disables display of discretionary ligatures (OpenType feature: <span
3716 class=tag>dlig</span>).
3718 <dt><dfn id=historical-ligatures>historical-ligatures</dfn>
3720 <dd>Enables display of historical ligatures (OpenType feature: <span
3721 class=tag>hlig</span>).
3722 </dl>
3724 <div class=featex><img alt="historical ligature example" src=hlig.png></div>
3726 <dl>
3727 <dt><dfn id=no-historical-ligatures>no-historical-ligatures</dfn>
3729 <dd>Disables display of historical ligatures (OpenType feature: <span
3730 class=tag>hlig</span>).
3732 <dt><dfn id=contextual>contextual</dfn>
3734 <dd>Enables display of contextual alternates (OpenType feature: <span
3735 class=tag>calt</span>). Although not strictly a ligature feature, like
3736 ligatures this feature is commonly used to harmonize the shapes of glyphs
3737 with the surrounding context. For OpenType fonts, this feature is on by
3738 default.
3739 </dl>
3741 <div class=featex><img alt="contextual alternate example" src=calt.png></div>
3743 <dl>
3744 <dt><dfn id=no-contextual>no-contextual</dfn>
3746 <dd>Disables display of contextual alternates (OpenType feature: <span
3747 class=tag>calt</span>).
3748 </dl>
3750 <p>Required ligatures, needed for correctly rendering complex scripts, are
3751 not affected by the settings above, including ‘<code
3752 class=property>none</code>’ (OpenType feature: <span
3753 class=tag>rlig</span>).</p>
3754 <!-- prop: font-variant-position -->
3756 <h3 id=font-variant-position-prop><span class=secno>6.5 </span>Subscript
3757 and superscript forms: the <a
3758 href="#propdef-font-variant-position">font-variant-position</a> property</h3>
3760 <table class=propdef id=namefont-variant-positionvaluenormal-sub>
3761 <tbody>
3762 <tr>
3763 <td>Name:
3765 <td><dfn id=propdef-font-variant-position>font-variant-position</dfn>
3767 <tr>
3768 <td>Value:
3770 <td><span title="normal!!font-variant-position">normal</span> |
3771 <span>sub</span> | <span>super</span>
3773 <tr>
3774 <td>Initial:
3776 <td>normal
3778 <tr>
3779 <td>Applies to:
3781 <td>all elements
3783 <tr>
3784 <td>Inherited:
3786 <td>yes
3788 <tr>
3789 <td>Percentages:
3791 <td>N/A
3793 <tr>
3794 <td>Media:
3796 <td>visual
3798 <tr>
3799 <td>Computed value:
3801 <td>as specified
3803 <tr>
3804 <td>Animatable:
3806 <td>no
3807 </table>
3809 <p>This property is used to enable typographic subscript and superscript
3810 glyphs. These are alternate glyphs designed within the same em-box as
3811 default glyphs and are intended to be laid out on the same baseline as the
3812 default glyphs, with no resizing or repositioning of the baseline. They
3813 are explicitly designed to match the surrounding text and to be more
3814 readable without affecting the line height.
3816 <div class=figure><img alt="comparison between real subscript glyphs and
3817 synthesized ones" src=realsubscripts.png>
3818 <p class=caption>Subscript glyphs (top) vs. typical synthesized subscripts
3819 (bottom)
3820 </div>
3822 <p>The values ‘<code class=property>sub</code>’ and ‘<code
3823 class=property>super</code>’ imply the appropriate variant glyph is
3824 displayed when available in the font (OpenType features: <span
3825 class=tag>subs, sups</span>). A value of ‘<code
3826 class=property>normal</code>’ specifies neither of these alternate
3827 glyphs are substituted.
3829 <p>Because of the semantic nature of subscripts and superscripts, when the
3830 value is either ‘<code class=property>sub</code>’ or ‘<code
3831 class=property>super</code>’ for a given contiguous run of text, if a
3832 variant glyph is not available for all the characters in the run,
3833 simulated glyphs must be synthesized for all characters using reduced
3834 forms of the glyphs that would be used without this feature applied. This
3835 is done to avoid a mixture of variant glyphs and synthesized ones that
3836 would not align correctly.
3838 <p>In the case of OpenType fonts that lack subscript or superscript glyphs
3839 for a given character, user agents must use the appropriate subscript and
3840 superscript metrics specified in the selected font's <a
3841 href="http://www.microsoft.com/typography/otspec/os2.htm#subxs">OS/2
3842 table</a> <a href="#OPENTYPE"
3843 rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a> to calculate the size
3844 and offset of the synthesized substitutes.
3846 <p>In the past, user agents have used font-size and vertical-align to
3847 simulate subscripts and superscripts for the <span class=tag>sub</span>
3848 and <span class=tag>sup</span> elements. To allow a backwards compatible
3849 way of defining subscripts and superscripts, it is recommended that
3850 authors use conditional rules <a href="#CSS3-CONDITIONAL"
3851 rel=biblioentry>[CSS3-CONDITIONAL]<!--{{CSS3-CONDITIONAL}}--></a> so that
3852 older user agents will still render subscripts and superscripts via the
3853 older mechanism.
3855 <p>Authors should note that fonts typically only provide subscript and
3856 superscript glyphs for a subset of all characters supported by the font.
3857 While subscript and superscript glyphs are often available for Latin
3858 numbers, glyphs for punctuation and letter characters are less frequently
3859 provided. The synthetic fallback rules defined for this property assure
3860 that subscripts and superscripts will always appear but the appearance may
3861 not match author expectations if the font used does not provide the
3862 appropriate alternate glyph for all characters contained in a subscript or
3863 superscript.
3865 <div class=figure><img alt="alternate superscripts vs. glyphs synthesized
3866 using superscript metrics" src=superscript-alt-synth.png>
3867 <p class=caption>Superscript alternate glyph (left), synthesized
3868 superscript glyphs (middle), and incorrect mixture of the two (right)
3869 </div>
3871 <p>This property is not cumulative, applying it to subelements within a
3872 subscript or superscript won't nest the placement of a subscript or
3873 superscript glyph. Images contained within text runs where the value of
3874 this property is ‘<code class=property>sub</code>’ or ‘<code
3875 class=property>super</code>’ will be drawn just as they would if the
3876 value was ‘<code class=property>normal</code>’. Likewise, text
3877 decorations such as underlines or emphasis marks will render in the same
3878 position as they would for the default glyphs, since this property does
3879 not affect the baseline position.
3881 <p>Because of these limitations, font-variant-position is not recommended
3882 for use in user agent stylesheets. Authors should use it in cases where
3883 subscripts or superscripts will only contain the narrow range of
3884 characters supported by the fonts specified.
3886 <div class=example>
3887 <p>A typical user agent default style for the <span class=tag>sub</span>
3888 element:</p>
3890 <pre>sub {
3891 vertical-align: sub;
3892 font-size: smaller;
3893 line-height: normal;
3894 }
3895 </pre>
3897 <p>Using font-variant-position to specify typographic subscripts in a way
3898 that will still show subscripts in older user agents:</p>
3900 <pre>@supports ( font-variant-position: sub ) {
3902 sub {
3903 vertical-align: inherit;
3904 font-size: 100%;
3905 line-height: inherit;
3906 font-variant-position: sub;
3907 }
3909 }
3910 </pre>
3912 <p>User agents that support the ‘<a
3913 href="#propdef-font-variant-position"><code
3914 class=property>font-variant-position</code></a>’ property will select a
3915 subscript variant glyph and render this without adjusting the baseline or
3916 font-size. Older user agents will ignore the ‘<a
3917 href="#propdef-font-variant-position"><code
3918 class=property>font-variant-position</code></a>’ property definition
3919 and use the standard defaults for subscripts.</p>
3920 </div>
3921 <!-- prop: font-variant-caps -->
3923 <h3 id=font-variant-caps-prop><span class=secno>6.6 </span>Capitalization:
3924 the <a href="#propdef-font-variant-caps">font-variant-caps</a> property</h3>
3926 <table class=propdef id=namefont-variant-capsvaluenormal-small-c>
3927 <tbody>
3928 <tr>
3929 <td>Name:
3931 <td><dfn id=propdef-font-variant-caps>font-variant-caps</dfn>
3933 <tr>
3934 <td>Value:
3936 <td><a href="#font-variant-caps-normal-value"
3937 title="normal!!font-variant-caps">normal</a> | <a
3938 href="#small-caps">small-caps</a> | <a
3939 href="#all-small-caps">all-small-caps</a> | <a
3940 href="#petite-caps">petite-caps</a> | <a
3941 href="#all-petite-caps">all-petite-caps</a> | <a
3942 href="#unicase">unicase</a> | <a href="#titling-caps">titling-caps</a>
3944 <tr>
3945 <td>Initial:
3947 <td>normal
3949 <tr>
3950 <td>Applies to:
3952 <td>all elements
3954 <tr>
3955 <td>Inherited:
3957 <td>yes
3959 <tr>
3960 <td>Percentages:
3962 <td>N/A
3964 <tr>
3965 <td>Media:
3967 <td>visual
3969 <tr>
3970 <td>Computed value:
3972 <td>as specified
3974 <tr>
3975 <td>Animatable:
3977 <td>no
3978 </table>
3980 <p>Specifies control over capitalized forms.
3982 <p>Individual values have the following meanings:
3984 <dl>
3985 <dt><dfn id=font-variant-caps-normal-value
3986 title="normal!!font-variant-caps">normal</dfn>
3988 <dd>None of the features listed below are enabled.
3990 <dt><dfn id=small-caps>small-caps</dfn>
3992 <dd>Enables display of small capitals (OpenType feature: <span
3993 class=tag>smcp</span>). Small-caps glyphs typically use the form of
3994 uppercase letters but are reduced to the size of lowercase letters.
3995 </dl>
3997 <div class=featex><img alt="small-caps example" src=smcp.png></div>
3999 <dl>
4000 <dt><dfn id=all-small-caps>all-small-caps</dfn>
4002 <dd>Enables display of small capitals for both upper and lowercase letters
4003 (OpenType features: <span class=tag>c2sc, smcp</span>).
4005 <dt><dfn id=petite-caps>petite-caps</dfn>
4007 <dd>Enables display of petite capitals (OpenType feature: <span
4008 class=tag>pcap</span>).
4010 <dt><dfn id=all-petite-caps>all-petite-caps</dfn>
4012 <dd>Enables display of petite capitals for both upper and lowercase
4013 letters (OpenType features: <span class=tag>c2pc, pcap</span>).
4015 <dt><dfn id=unicase>unicase</dfn>
4017 <dd>Enables display of mixture of small capitals for uppercase letters
4018 with normal lowercase letters (OpenType feature: <span
4019 class=tag>unic</span>).
4021 <dt><dfn id=titling-caps>titling-caps</dfn>
4023 <dd>Enables display of titling capitals (OpenType feature: <span
4024 class=tag>titl</span>). Uppercase letter glyphs are often designed for
4025 use with lowercase letters. When used in all uppercase titling sequences
4026 they can appear too strong. Titling capitals are designed specifically
4027 for this situation.
4028 </dl>
4030 <p>This property allows the selection of alternate glyphs used for small or
4031 petite capitals or for titling. These glyphs are specifically designed to
4032 blend well with the surrounding normal glyphs, to maintain the weight and
4033 readability which suffers when text is simply resized to fit this purpose.
4035 <p>The availability of these glyphs is based on whether a given feature is
4036 defined or not in the feature list of the font. User agents can optionally
4037 decide this on a per-script basis but should explicitly not decide this on
4038 a per-character basis.
4040 <p>Some fonts may only support a subset or none of the features described
4041 for this property. For backwards compatibility with CSS 2.1, if ‘<a
4042 href="#small-caps"><code class=property>small-caps</code></a>’ or ‘<a
4043 href="#all-small-caps"><code class=property>all-small-caps</code></a>’
4044 is specified but small-caps glyphs are not available for a given font,
4045 user agents should simulate a small-caps font, for example by taking a
4046 normal font and replacing the glyphs for lowercase letters with scaled
4047 versions of the glyphs for uppercase characters (replacing the glyphs for
4048 both upper and lowercase letters in the case of ‘<a
4049 href="#all-small-caps"><code class=property>all-small-caps</code></a>’).
4051 <div class=figure style="padding: 0; margin: auto;"><img alt="synthetic vs.
4052 real small-caps" class=hires src=synthetic-vs-real-small-caps.png
4053 width=512px>
4054 <p class=caption>Synthetic vs. real small-caps
4055 </div>
4057 <p>To match the surrounding text, a font may provide alternate glyphs for
4058 caseless characters when these features are enabled but when a user agent
4059 simulates small capitals, it must not attempt to simulate alternates for
4060 codepoints which are considered caseless.
4062 <div class=figure style="padding: 0; margin: auto;"><img alt="caseless
4063 characters with small-caps, all-small-caps enabled" class=hires
4064 src=small-capitals-variations.png width=418px>
4065 <p class=caption>Caseless characters with small-caps, all-small-caps
4066 enabled
4067 </div>
4069 <p>If either ‘<a href="#petite-caps"><code
4070 class=property>petite-caps</code></a>’ or ‘<a
4071 href="#all-petite-caps"><code class=property>all-petite-caps</code></a>’
4072 is specified for a font that doesn't support these features, the property
4073 behaves as if ‘<a href="#small-caps"><code
4074 class=property>small-caps</code></a>’ or ‘<a
4075 href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
4076 respectively, had been specified. If ‘<a href="#unicase"><code
4077 class=property>unicase</code></a>’ is specified for a font that doesn't
4078 support that feature, the property behaves as if ‘<a
4079 href="#small-caps"><code class=property>small-caps</code></a>’ was
4080 applied only to lowercased uppercase letters. If ‘<a
4081 href="#titling-caps"><code class=property>titling-caps</code></a>’ is
4082 specified with a font that does not support this feature, this property
4083 has no visible effect. When simulated small capital glyphs are used, for
4084 scripts that lack uppercase and lowercase letters, ‘<a
4085 href="#small-caps"><code class=property>small-caps</code></a>’, ‘<a
4086 href="#all-small-caps"><code class=property>all-small-caps</code></a>’,
4087 ‘<a href="#petite-caps"><code class=property>petite-caps</code></a>’,
4088 ‘<a href="#all-petite-caps"><code
4089 class=property>all-petite-caps</code></a>’ and ‘<a
4090 href="#unicase"><code class=property>unicase</code></a>’ have no visible
4091 effect.
4093 <p>When casing transforms are used to simulate small capitals, the casing
4094 transformations should match those used for the <span
4095 class=property>‘<code class=property>text-transform</code>’</span>
4096 property.
4098 <p>As a last resort, unscaled uppercase letter glyphs in a normal font may
4099 replace glyphs in a small-caps font so that the text appears in all
4100 uppercase letters.
4102 <div class=figure style="padding: 0; margin: auto;"><img alt="using
4103 all-small-caps in acronym-laden text" class=hires
4104 src=acronym-laden-text.png width=596px>
4105 <p class=caption>Using small capitals to improve readability in
4106 acronym-laden text
4107 </div>
4109 <div class=example>
4110 <p>Quotes rendered italicised, with small-caps on the first line:</p>
4112 <pre>blockquote { font-style: italic; }
4113 blockquote:first-line { font-variant: small-caps; }
4115 <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>
4116 </pre>
4117 </div>
4118 <!-- prop: font-variant-numeric -->
4120 <h3 id=font-variant-numeric-prop><span class=secno>6.7 </span>Numerical
4121 formatting: the <a
4122 href="#propdef-font-variant-numeric">font-variant-numeric</a> property</h3>
4124 <table class=propdef id=namefont-variant-numericvaluenormal-ltnu>
4125 <tbody>
4126 <tr>
4127 <td>Name:
4129 <td><dfn id=propdef-font-variant-numeric>font-variant-numeric</dfn>
4131 <tr>
4132 <td>Value:
4134 <td><a href="#font-variant-numeric-normal-value"
4135 title="normal!!font-variant-numeric">normal</a> | [ <a
4136 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
4137 || <a
4138 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
4139 || <a
4140 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
4141 || <a href="#ordinal">ordinal</a> || <a
4142 href="#slashed-zero">slashed-zero</a> ]
4144 <tr>
4145 <td>Initial:
4147 <td>normal
4149 <tr>
4150 <td>Applies to:
4152 <td>all elements
4154 <tr>
4155 <td>Inherited:
4157 <td>yes
4159 <tr>
4160 <td>Percentages:
4162 <td>N/A
4164 <tr>
4165 <td>Media:
4167 <td>visual
4169 <tr>
4170 <td>Computed value:
4172 <td>as specified
4174 <tr>
4175 <td>Animatable:
4177 <td>no
4178 </table>
4180 <p>Specifies control over numerical forms.
4182 <pre
4183 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>
4185 <pre
4186 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>
4188 <pre
4189 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>
4191 <p>Individual values have the following meanings:
4193 <dl>
4194 <dt><dfn id=font-variant-numeric-normal-value
4195 title="normal!!font-variant-numeric">normal</dfn>
4197 <dd>None of the features listed below are enabled.
4199 <dt><dfn id=lining-nums>lining-nums</dfn>
4201 <dd>Enables display of lining numerals (OpenType feature: <span
4202 class=tag>lnum</span>).
4204 <dt><dfn id=oldstyle-nums>oldstyle-nums</dfn>
4206 <dd>Enables display of old-style numerals (OpenType feature: <span
4207 class=tag>onum</span>).
4209 <dt><dfn id=proportional-nums>proportional-nums</dfn>
4211 <dd>Enables display of proportional numerals (OpenType feature: <span
4212 class=tag>pnum</span>).
4214 <dt><dfn id=tabular-nums>tabular-nums</dfn>
4216 <dd>Enables display of tabular numerals (OpenType feature: <span
4217 class=tag>tnum</span>).
4218 </dl>
4220 <p>The example below shows how these different properties can be combined
4221 to influence the rendering of tabular data with fonts that support these
4222 features. Within normal paragraph text, proportional numbers are used
4223 while tabular numbers are used so that columns of numbers line up
4224 properly:
4226 <div class=figure style="padding: 0; margin: auto;"><img alt="combining
4227 number styles" src=numberstyles.png>
4228 <p class=caption>Using number styles
4229 </div>
4231 <dl>
4232 <dt><dfn id=diagonal-fractions>diagonal-fractions</dfn>
4234 <dd>Enables display of lining diagonal fractions (OpenType feature: <span
4235 class=tag>frac</span>).
4236 </dl>
4238 <div class=featex><img alt="diagonal fraction example" src=frac.png></div>
4240 <dl>
4241 <dt><dfn id=stacked-fractions>stacked-fractions</dfn>
4243 <dd>Enables display of lining stacked fractions (OpenType feature: <span
4244 class=tag>afrc</span>).
4245 </dl>
4247 <div class=featex><img alt="stacked fraction example" src=afrc.png></div>
4249 <dl>
4250 <dt><dfn id=ordinal>ordinal</dfn>
4252 <dd>Enables display of forms used with ordinal numbers (OpenType feature:
4253 <span class=tag>ordn</span>).
4255 <dt><dfn id=slashed-zero>slashed-zero</dfn>
4257 <dd>Enables display of slashed zeros (OpenType feature: <span
4258 class=tag>zero</span>).
4259 </dl>
4261 <div class=featex><img alt="slashed zero example" src=zero.png></div>
4263 <div class=example id=steak-marinade>
4264 <p>A simple flank steak marinade recipe, rendered with automatic fractions
4265 and old-style numerals:</p>
4267 <pre>.amount { font-variant-numeric: oldstyle-nums diagonal-fractions; }
4269 <h4>Steak marinade:</h4>
4270 <ul>
4271 <li><span class="amount">2</span> tbsp olive oil</li>
4272 <li><span class="amount">1</span> tbsp lemon juice</li>
4273 <li><span class="amount">1</span> tbsp soy sauce</li>
4274 <li><span class="amount">1 1/2</span> tbsp dry minced onion</li>
4275 <li><span class="amount">2 1/2</span> tsp italian seasoning</li>
4276 <li>Salt &amp; pepper</li>
4277 </ul>
4279 <p>Mix the meat with the marinade and let it sit covered in the refrigerator
4280 for a few hours or overnight.</p>
4281 </pre>
4282 </div>
4283 <!-- prop: font-variant-alternates -->
4285 <h3 id=font-variant-alternates-prop><span class=secno>6.8 </span>Alternates
4286 and swashes: the <a
4287 href="#propdef-font-variant-alternates">font-variant-alternates</a>
4288 property</h3>
4290 <table class=propdef id=namefont-variant-alternatesvaluenormal-s>
4291 <tbody>
4292 <tr>
4293 <td>Name:
4295 <td><dfn
4296 id=propdef-font-variant-alternates>font-variant-alternates</dfn>
4298 <tr>
4299 <td>Value:
4301 <td>normal | [ <a href="#stylistic"
4302 title=stylistic>stylistic(<feature-value-name>)</a> || <a
4303 href="#historical-forms">historical-forms</a> || <a href="#styleset"
4304 title=styleset>styleset(<feature-value-name> #)</a> || <a
4305 href="#character-variant"
4306 title=character-variant>character-variant(<feature-value-name>
4307 #)</a> || <a href="#swash"
4308 title=swash>swash(<feature-value-name>)</a> || <a
4309 href="#ornaments"
4310 title=ornaments>ornaments(<feature-value-name>)</a> || <a
4311 href="#annotation"
4312 title=annotation>annotation(<feature-value-name>)</a> ]
4314 <tr>
4315 <td>Initial:
4317 <td>normal
4319 <tr>
4320 <td>Applies to:
4322 <td>all elements
4324 <tr>
4325 <td>Inherited:
4327 <td>yes
4329 <tr>
4330 <td>Percentages:
4332 <td>N/A
4334 <tr>
4335 <td>Media:
4337 <td>visual
4339 <tr>
4340 <td>Computed value:
4342 <td>as specified
4344 <tr>
4345 <td>Animatable:
4347 <td>no
4348 </table>
4350 <p>For any given character, fonts can provide a variety of alternate glyphs
4351 in addition to the default glyph for that character. This property
4352 provides control over the selection of these alternate glyphs.
4354 <p>In cases where multiple alternates are possible, authors define a
4355 <code><feature-value-name></code> using the
4356 <code>@font-feature-values</code> rule described below to indicate the
4357 specific alternate to be used. The nature of these alternates is font
4358 specific, so the rule defines values for a specific font family or set of
4359 families. When a particular value has not been defined for a given family,
4360 the named value is treated as if the feature had omitted from the style
4361 rule. If a given value is outside the range supported by a given font, the
4362 value is ignored. These values never apply to generic font families, nor
4363 to families selected as part of system font fallback. Values that behave
4364 this way are marked as <em>font specific</em>.
4366 <p>Individual values have the following meanings:
4368 <dl>
4369 <dt><dfn id=font-variant-alternates-normal-value
4370 title="normal!!font-variant-alternates">normal</dfn>
4372 <dd>None of the features listed below are enabled.
4374 <dt><dfn id=stylistic
4375 title=stylistic>stylistic(<feature-value-name>)</dfn>
4377 <dd>Enables display of stylistic alternates (<em>font specific</em>,
4378 OpenType feature: <span class=tag>salt
4379 <feature-value-name></span>).
4380 </dl>
4382 <div class=featex><img alt="stylistic alternate example" src=salt.png></div>
4384 <dl>
4385 <dt><dfn id=historical-forms>historical-forms</dfn>
4387 <dd>Enables display of historical forms (OpenType feature: <span
4388 class=tag>hist</span>).
4389 </dl>
4391 <div class=featex><img alt="historical form example" src=hist.png></div>
4393 <dl>
4394 <dt><dfn id=styleset title=styleset>styleset(<feature-value-name>
4395 #)</dfn>
4397 <dd>Enables display with stylistic sets (<em>font specific</em>, OpenType
4398 feature: <span class=tag>ss<feature-index></span> OpenType
4399 currently defines <span class=tag>ss01</span> through <span
4400 class=tag>ss20</span>).
4401 </dl>
4403 <div class=featex><img alt="styleset example" src=ssnn.png></div>
4405 <dl>
4406 <dt><dfn id=character-variant
4407 title=character-variant>character-variant(<feature-value-name>
4408 #)</dfn>
4410 <dd>Enables display of specific character variants (<em>font
4411 specific</em>, OpenType feature: <span
4412 class=tag>cv<feature-index></span> OpenType currently defines <span
4413 class=tag>cv01</span> through <span class=tag>cv99</span>).
4415 <dt><dfn id=swash title=swash>swash(<feature-value-name>)</dfn>
4417 <dd>Enables display of swash glyphs (<em>font specific</em>, OpenType
4418 feature: <span class=tag>swsh <feature-index>, cswh
4419 <feature-index></span>).
4420 </dl>
4422 <div class=featex><img alt="swash example" src=swsh.png></div>
4424 <dl>
4425 <dt><dfn id=ornaments
4426 title=ornaments>ornaments(<feature-value-name>)</dfn>
4428 <dd>Enables replacement of default glyphs with ornaments, if provided in
4429 the font (<em>font specific</em>, OpenType feature: <span class=tag>ornm
4430 <feature-index></span>). Some fonts may offer ornament glyphs as
4431 alternates for a wide collection of characters; however, displaying
4432 arbitrary characters (e.g., alphanumerics) as ornaments is poor practice
4433 as it distorts the semantics of the data. Font designers are encouraged
4434 to encode all ornaments (except those explicitly encoded in the Unicode
4435 Dingbats blocks, etc.) as alternates for the bullet character (U+2022) to
4436 allow authors to select the desired glyph using
4437 <feature-value-name>.
4438 </dl>
4440 <div class=featex><img alt="ornaments example" src=ornm.png></div>
4442 <dl>
4443 <dt><dfn id=annotation
4444 title=annotation>annotation(<feature-value-name>)</dfn>
4446 <dd>Enables display of alternate annotation forms (<em>font specific</em>,
4447 OpenType feature: <span class=tag>nalt <feature-index></span>).
4448 </dl>
4450 <div class=featex><img alt="alternate annotation form example"
4451 src=nalt.png></div>
4453 <h3 id=font-feature-values><span class=secno>6.9 </span>Defining font
4454 specific alternates: the <code>@font-feature-values</code> rule</h3>
4456 <p>Several of the possible values of ‘<a
4457 href="#propdef-font-variant-alternates"><code
4458 class=property>font-variant-alternates</code></a>’ listed above are
4459 labeled as "font specific". For these features fonts may define not just a
4460 single glyph but a set of alternate glyphs with an index to select a given
4461 alternate. Since these are font family specific, the
4462 <code>@font-feature-values</code> rule is used to define named-values for
4463 these indices for a given family.
4465 <p>In the case of the swash Q in the example shown above, the swash could
4466 be specified using these style rules:
4468 <pre>
4470 @font-feature-values Jupiter Sans {
4471 @swash {
4472 delicate: 1;
4473 flowing: 2;
4474 }
4475 }
4477 h2 { font-family: Jupiter Sans, sans-serif; }
4479 /* show the second swash variant in h2 headings */
4480 h2:first-letter { font-variant-alternates: swash(flowing); }
4482 <h2>Quick</h2></pre>
4484 <p>When Jupiter Sans is present, the second alternate swash alternate will
4485 be displayed. When not present, no swash character will be shown, since
4486 the specific named-value "flowing" is only defined for the Jupiter Sans
4487 family. The @-mark indicates the name of the property value for which a
4488 named-value can be used. The name "flowing" is chosen by the author, the
4489 values specified within a given font's data.
4491 <p>In terms of the grammar, this specification defines the following
4492 productions:</p>
4493 <!--
4494 <pre><dfn>supports_rule</dfn>
4495 : <i>SUPPORTS_SYM</i> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <i>supports_condition</i> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <i>group_rule_body</i>
4496 ;
4498 <dfn>supports_condition</dfn>
4499 : <i>supports_negation</i> | <i>supports_conjunction</i> | <i>supports_disjunction</i> |
4500 <i>supports_condition_in_parens</i>
4501 ;
4503 <dfn>supports_condition_in_parens</dfn>
4504 : ( '(' <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* <i>supports_condition</i> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>* ')' ) | <i>supports_declaration_condition</i> |
4505 <i>general_enclosed</i>
4506 ;
4508 <dfn>supports_negation</dfn>
4509 : <a href="http://www.w3.org/TR/css3-mediaqueries/#syntax"><i>NOT</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>+ <i>supports_condition_in_parens</i>
4510 ;
4512 <dfn>supports_conjunction</dfn>
4513 : <i>supports_condition_in_parens</i> ( <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>+ <a href="http://www.w3.org/TR/css3-mediaqueries/#syntax"><i>AND</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>+ <i>supports_condition_in_parens</i> )+
4514 ;
4516 <dfn>supports_disjunction</dfn>
4517 : <i>supports_condition_in_parens</i> ( <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>+ <i>OR</i> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>+ <i>supports_condition_in_parens</i> )+
4518 ;
4520 <dfn>supports_declaration_condition</dfn>
4521 : '(' <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>declaration</i></a> ')'
4522 ;
4524 <dfn>general_enclosed</dfn>
4525 : ( <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>FUNCTION</i></a> | '(' ) ( <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>any</i></a> | <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>unused</i></a> )* ')'
4526 ;
4527 </pre>
4529 -->
4531 <pre><dfn id=fontfeaturevaluesrule>font_feature_values_rule</dfn>
4532 : <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>*
4533 '{' <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>*
4534 ;
4536 <dfn id=fontfamilynamelist>font_family_name_list</dfn>
4537 : <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> ]*
4538 ;
4540 <dfn id=fontfamilyname>font_family_name</dfn>
4541 : <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> ]* ]
4542 ;
4544 <dfn id=featurevalueblock>feature_value_block</dfn>
4545 : <a href="#featuretype"><i>feature_type</i></a> <a href="http://www.w3.org/TR/CSS21/grammar.html#scanner"><i>S</i></a>*
4546 '{' <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>*
4547 ;
4549 <dfn id=featuretype>feature_type</dfn>:
4550 <a href="http://www.w3.org/TR/CSS21/syndata.html#tokenization"><i>ATKEYWORD</i></a>
4551 ;
4553 <dfn id=featurevaluedefinition>feature_value_definition</dfn>
4554 : <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> ]*
4555 ;
4556 </pre>
4558 <p>The following new token is introduced:
4560 <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>;}
4561 </pre>
4563 <p>Feature value blocks are treated <a
4564 href="http://www.w3.org/TR/CSS2/syndata.html#at-rules">similar to
4565 at-rules</a>, they consist of everything up to the next block or
4566 semi-colon, whichever comes first.
4568 <p>Font feature values rules define a set of values for a specific font
4569 feature as used for a given set of families. Effectively, they define a
4570 mapping of ⟨family, feature, ident⟩ → ⟨values⟩ where
4571 ⟨values⟩ are the indices used for specific features defined for a
4572 given font.
4574 <p>The font family list uses the same syntax as that used for the <a
4575 href="#propdef-font-family" title="font-family!!property">‘<code
4576 class=property>font-family</code>’</a> property. Within feature value
4577 blocks, the feature type is ‘<code class=css>@</code>’ followed by the
4578 name of the font-specific property value (e.g. <a
4579 href="#swash"><code>@swash</code></a>). The feature type must match, using
4580 an ASCII case-insensitive comparison, one of the <em>font specific</em>
4581 values of the ‘<a href="#propdef-font-variant-alternates"><code
4582 class=property>font-variant-alternates</code></a>’ property. The values
4583 associated with a given idenitifier are limited to integer values 0 or
4584 greater.
4586 <p>If syntax errors occur within the font family list, the entire rule must
4587 be ignored. When syntax errors occur within a feature value definition,
4588 such as invalid identifiers or values, the entire feature value definition
4589 must be omitted, similar to the way syntax errors in style declarations
4590 are handled. When the <code><feature-type></code> is invalid, the
4591 entire associated feature value block must be ignored.
4593 <pre>@font-feature-values Bongo {
4594 @swash { ornate: 1; }
4595 annotation { boxed: 4; } /* should be @annotation! */
4596 @swash { double-loops: 1; flowing: -1; } /* negative value */
4597 @ornaments ; /* incomplete definition */
4598 @styleset { double-W: 14; sharp-terminals: 16 1 } /* missing ; */
4599 <a href="http://www.angryalien.com/0504/shiningbunnies.html" style="text-decoration: none;">redrum</a> /* random editing mistake */
4600 }</pre>
4602 <p>The example above is equivalent to:
4604 <pre>@font-feature-values Bongo {
4605 @swash { ornate: 1; }
4606 @swash { double-loops: 1; }
4607 @styleset { double-W: 14; sharp-terminals: 16 1; }
4608 }</pre>
4610 <p>If multiple <code>@font-feature-values</code> rules are defined for a
4611 given family, the resulting values defined are the union of these rules.
4612 This allows a set of named-values to be defined for a given font family
4613 globally for a site and specific additions made per-page. If the same
4614 <feature-value-name> is defined mulitple times for a given
4615 font-variant value, the last defined value is used.
4617 <pre>
4618 site.css:
4620 @font-feature-values Mercury Serif {
4621 @styleset {
4622 stacked-g: 3; /* "two-storey" versions of g, a */
4623 stacked-a: 4;
4624 }
4625 }
4627 page.css:
4629 @font-feature-values Mercury Serif {
4630 @styleset {
4631 geometric-m: 7; /* alternate version of m */
4632 }
4633 }
4635 body {
4636 font-family: Mercury Serif, serif;
4638 /* enable both the use of stacked g and alternate m */
4639 font-variant-alternates: styleset(stacked-g, geometric-m);
4640 }</pre>
4642 <p>Only named font families are allowed for <font-family>, rules that
4643 include generic or system fonts in the list of font families are
4644 considered syntax errors and the contents of the rules are ignored.
4645 However, if a user agent defines a generic font to be a specific named
4646 font (e.g. Helvetica), the settings associated with that family name will
4647 be used.
4649 <p>For <font-variant-property-value>, only font specific property value
4650 names supported by the <a href="#propdef-font-variant"
4651 title="font-variant!!property">‘<code
4652 class=property>font-variant</code>’</a> property are recognized,
4653 definitions for other value names cause a syntax error and are ignored.
4654 Each property value that is font specific is clearly marked as such.
4655 Feature value names follow the rules of CSS user identifiers and are
4656 case-sensitive. They are unique only for a given set of font families and
4657 font-variant property value; the same identifier used with a different
4658 font-variant property value is treated as a separate and distinct value.
4660 <p>Using a commonly named value allows authors to use a single style rule
4661 to cover a set of fonts for which the underlying selector is different for
4662 each font. If either font in the example below is found, a circled number
4663 glyph will be used:
4665 <pre>@font-feature-values Taisho Gothic {
4666 @annotation { boxed: 1; circled: 4; }
4667 }
4669 @font-feature-values Otaru Kisa {
4670 @annotation { circled: 1; black-boxed: 3; }
4671 }
4673 h3.title {
4674 /* circled form defined for both fonts */
4675 font-family: Taisho Gothic, Otaru Kisa;
4676 font-variant: annotation(circled);
4677 }</pre>
4679 <p>Most font specific font-variant property values take a single value
4680 (e.g. swash). The character-variant property value allows two values and
4681 styleset allows an unlimited number. If a larger number of values are
4682 assigned to a given name, a syntax error occurs and the entire
4683 <font-feature-values-declaration> is ignored.
4685 <p>For the styleset property value, multiple values indicate the style sets
4686 to be enabled. Values between 1 and 99 enable OpenType features <span
4687 class=tag>ss01</span> through <span class=tag>ss99</span>. However, the
4688 OpenType standard only officially defines <span class=tag>ss01</span>
4689 through <span class=tag>ss20</span>. Values greater than 99 or equal to 0
4690 are ignored but do not generate a syntax error when parsed.
4692 <pre>@font-feature-values Mars Serif {
4693 @styleset {
4694 alt-g: 1; /* implies ss01 = 1 */
4695 curly-quotes: 3; /* implies ss03 = 1 */
4696 code: 4 5; /* implies ss04 = 1, ss05 = 1 */
4697 }
4699 @styleset {
4700 dumb: 125; /* >99, ignored */
4701 }
4703 @swash {
4704 swishy: 3 5; /* more than 1 value for swash, syntax error */
4705 }
4706 }
4708 p.codeblock {
4709 /* implies ss03 = 1, ss04 = 1, ss05 = 1 */
4710 font-variant-alternates: styleset(curly-quotes, code);
4711 }</pre>
4713 <p>For character-variant, a single value between 1 and 99 indicates the
4714 enabling of OpenType feature <span class=tag>cv01</span> through <span
4715 class=tag>cv99</span>. For OpenType fonts, values greater than 99 or equal
4716 to 0 are ignored but do not generate a syntax error when parsed. When two
4717 values are listed, the first value indicates the feature used and the
4718 second the value passed for that feature. When two value names imply
4719 different settings for the same underlying feature the last setting is
4720 used.
4722 <pre>@font-feature-values MM Greek {
4723 @character-variant { alpha-2: 1 2; } /* implies cv01 = 2 */
4724 @character-variant { beta-3: 2 3; } /* implies cv02 = 3 */
4725 @character-variant { epsilon: 5 3 6; } /* more than 2 values, syntax error, ignored */
4726 @character-variant { gamma: 12; } /* implies cv12 = 1 */
4727 @character-variant { zeta: 20 3; } /* implies cv20 = 3 */
4728 @character-variant { zeta-2: 20 2; } /* implies cv20 = 2 */
4729 @character-variant { silly: 105; } /* >99, ignored */
4730 @character-variant { dumb: 323 3; } /* >99, ignored */
4731 }
4733 #title {
4734 /* use the third alternate beta, first alternate gamma */
4735 font-variant-alternates: character-variant(beta-3, gamma);
4736 }
4738 p {
4739 /* zeta-2 follows zeta, implies cv20 = 2 */
4740 font-variant-alternates: character-variant(zeta, zeta-2);
4741 }
4743 .special {
4744 /* zeta follows zeta-2, implies cv20 = 3 */
4745 font-variant-alternates: character-variant(zeta-2, zeta);
4746 }</pre>
4748 <p>See the <a href="#om-fontfeaturevalues">object model reference
4749 section</a> for a description of the interfaces used to modify these rules
4750 via the CSS Object Model.
4752 <div class=figure><img alt="Matching text on Byzantine seals using
4753 character variants" src=byzantineseal.png>
4754 <p class=caption>Byzantine seal text displayed with character variants
4755 </div>
4757 <div class=example>
4758 <p>In the figure above, the text in red is rendered using a font
4759 containing character variants that mimic the character forms found on a
4760 Byzantine seal from the 8th century A.D. Two lines below is the same text
4761 displayed in a font without variants. Note the two variants for U and N
4762 used on the seal.</p>
4764 <pre>@font-feature-values Athena Ruby {
4765 @character-variant {
4766 leo-B: 2 1;
4767 leo-M: 13 3;
4768 leo-alt-N: 14 1;
4769 leo-N: 14 2;
4770 leo-T: 20 1;
4771 leo-U: 21 2;
4772 leo-alt-U: 21 4;
4773 }
4774 }
4776 p {
4777 font-variant: discretionary-ligatures,
4778 character-variant(leo-B, leo-M, leo-N, leo-T, leo-U);
4779 }
4781 span.alt-N {
4782 font-variant-alternates: character-variant(leo-alt-N);
4783 }
4785 span.alt-U {
4786 font-variant-alternates: character-variant(leo-alt-U);
4787 }
4789 <p>ENO....UP͞RSTU<span class="alt-U">U</span>͞<span class="alt-U">U</span>ΚΑΙTỤẠG̣IUPNS</p>
4791 <p>LEON|ΚΑΙCONSTA|NTI<span class="alt-N">N</span>OS..|STOIBAṢ.|LIṢROM|AIO<span class="alt-N">N</span></p>
4792 </pre>
4793 </div>
4795 <h3 id=font-variant-east-asian-prop><span class=secno>6.10 </span>East
4796 Asian text rendering: the <a
4797 href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
4798 property</h3>
4800 <table class=propdef id=namefont-variant-east-asianvaluenormal-l>
4801 <tbody>
4802 <tr>
4803 <td>Name:
4805 <td><dfn
4806 id=propdef-font-variant-east-asian>font-variant-east-asian</dfn>
4808 <tr>
4809 <td>Value:
4811 <td><a href="#font-variant-east-asian-normal-value"
4812 title="normal!!font-variant-east-asian">normal</a> | [ <a
4813 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
4814 || <a
4815 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
4816 || <a href="#ruby">ruby</a> ]
4818 <tr>
4819 <td>Initial:
4821 <td>normal
4823 <tr>
4824 <td>Applies to:
4826 <td>all elements
4828 <tr>
4829 <td>Inherited:
4831 <td>yes
4833 <tr>
4834 <td>Percentages:
4836 <td>N/A
4838 <tr>
4839 <td>Media:
4841 <td>visual
4843 <tr>
4844 <td>Computed value:
4846 <td>as specified
4848 <tr>
4849 <td>Animatable:
4851 <td>no
4852 </table>
4854 <p>Allows control of glyph substitution and sizing in East Asian text.
4856 <pre
4857 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>
4859 <pre
4860 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>
4862 <p>Individual values have the following meanings:
4864 <dl>
4865 <dt><dfn id=font-variant-east-asian-normal-value
4866 title="normal!!font-variant-east-asian">normal</dfn>
4868 <dd>None of the features listed below are enabled.
4870 <dt><dfn id=jis78>jis78</dfn>
4872 <dd>Enables rendering of JIS78 forms (OpenType feature: <span
4873 class=tag>jp78</span>).
4874 </dl>
4876 <div class=featex><img alt="JIS78 form example" src=jp78.png></div>
4878 <dl>
4879 <dt><dfn id=jis83>jis83</dfn>
4881 <dd>Enables rendering of JIS83 forms (OpenType feature: <span
4882 class=tag>jp83</span>).
4884 <dt><dfn id=jis90>jis90</dfn>
4886 <dd>Enables rendering of JIS90 forms (OpenType feature: <span
4887 class=tag>jp90</span>).
4889 <dt><dfn id=jis04>jis04</dfn>
4891 <dd>Enables rendering of JIS2004 forms (OpenType feature: <span
4892 class=tag>jp04</span>).
4893 <p>The various JIS variants reflect the glyph forms defined in different
4894 Japanese national standards. Fonts generally include glyphs defined by
4895 the most recent national standard but it's sometimes necessary to use
4896 older variants, to match signage for example.</p>
4898 <dt><dfn id=simplified>simplified</dfn>
4900 <dd>Enables rendering of simplified forms (OpenType feature: <span
4901 class=tag>smpl</span>).
4902 <p>The ‘<a href="#simplified"><code
4903 class=property>simplified</code></a>’ and ‘<a
4904 href="#traditional"><code class=property>traditional</code></a>’
4905 values allow control over the glyph forms for characters which have been
4906 simplified over time but for which the older, traditional form is still
4907 used in some contexts. The exact set of characters and glyph forms will
4908 vary to some degree by context for which a given font was designed.</p>
4910 <dt><dfn id=traditional>traditional</dfn>
4912 <dd>Enables rendering of traditional forms (OpenType feature: <span
4913 class=tag>trad</span>).
4914 </dl>
4916 <div class=featex><img alt="tradtional form example" src=trad.png></div>
4918 <dl>
4919 <dt><dfn id=full-width>full-width</dfn>
4921 <dd>Enables rendering of full-width variants (OpenType feature: <span
4922 class=tag>fwid</span>).
4924 <dt><dfn id=proportional-width>proportional-width</dfn>
4926 <dd>Enables rendering of proportionally-spaced variants (OpenType feature:
4927 <span class=tag>pwid</span>).
4928 </dl>
4930 <div class=featex><img alt="proportionally spaced Japanese example"
4931 src=pwid.png></div>
4933 <dl>
4934 <dt><dfn id=ruby>ruby</dfn>
4936 <dd>Enables display of ruby variant glyphs (OpenType feature: <span
4937 class=tag>ruby</span>). Since ruby text is generally smaller than the
4938 associated body text, font designers can design special glyphs for use
4939 with ruby that are more readable than scaled down versions of the default
4940 glyphs. Only glyph selection is affected, there is no associated font
4941 scaling or other change that affects line layout. The red ruby text below
4942 is shown with default glyphs (top) and with ruby variant glyphs (bottom).
4943 Note the slight difference in stroke thickness.
4944 </dl>
4946 <div class=featex><img alt="ruby variant example" src=rubyshinkansen.png></div>
4948 <h3 id=font-variant-prop><span class=secno>6.11 </span>Overall shorthand
4949 for font rendering: the <a href="#propdef-font-variant">font-variant</a>
4950 property</h3>
4952 <table class=propdef id=namefont-variantvaluenormal-none-ltcommo>
4953 <tbody>
4954 <tr>
4955 <td>Name:
4957 <td><dfn id=propdef-font-variant
4958 title="font-variant!!property">font-variant</dfn>
4960 <tr>
4961 <td>Value:
4963 <td><a href="#font-variant-normal-value"
4964 title="normal!!font-variant">normal</a> | <a
4965 href="#font-variant-none-value" title="none!!font-variant">none</a> | [
4966 <a href="#common-lig-values"><var><common-lig-values></var></a>
4967 || <a
4968 href="#discretionary-lig-values"><var><discretionary-lig-values></var></a>
4969 || <a
4970 href="#historical-lig-values"><var><historical-lig-values></var></a>
4971 || <a
4972 href="#contextual-alt-values"><var><contextual-alt-values></var></a>
4973 || <a href="#stylistic"><var
4974 title=stylistic>stylistic(<feature-value-name>)</var></a> || <a
4975 href="#historical-forms"><var>historical-forms</var></a> || <a
4976 href="#styleset"><var
4977 title=styleset>styleset(<feature-value-name> #)</var></a> || <a
4978 href="#character-variant"><var
4979 title=character-variant>character-variant(<feature-value-name>
4980 #)</var></a> || <a href="#swash"><var
4981 title=swash>swash(<feature-value-name>)</var></a> || <a
4982 href="#ornaments"><var
4983 title=ornaments>ornaments(<feature-value-name>)</var></a> || <a
4984 href="#annotation"><var
4985 title=annotation>annotation(<feature-value-name>)</var></a> || [
4986 <a href="#small-caps"><i>small-caps</i></a> | <a
4987 href="#all-small-caps"><i>all-small-caps</i></a> | <a
4988 href="#petite-caps"><i>petite-caps</i></a> | <a
4989 href="#all-petite-caps"><i>all-petite-caps</i></a> | <a
4990 href="#unicase"><i>unicase</i></a> | <a
4991 href="#titling-caps"><i>titling-caps</i></a> ] || <a
4992 href="#numeric-figure-values"><var><numeric-figure-values></var></a>
4993 || <a
4994 href="#numeric-spacing-values"><var><numeric-spacing-values></var></a>
4995 || <a
4996 href="#numeric-fraction-values"><var><numeric-fraction-values></var></a>
4997 || <a href="#ordinal"><i>ordinal</i></a> || <a
4998 href="#slashed-zero"><i>slashed-zero</i></a> || <a
4999 href="#east-asian-variant-values"><var><east-asian-variant-values></var></a>
5000 || <a
5001 href="#east-asian-width-values"><var><east-asian-width-values></var></a>
5002 || <a href="#ruby"><i>ruby</i></a> ]
5004 <tr>
5005 <td>Initial:
5007 <td>normal
5009 <tr>
5010 <td>Applies to:
5012 <td>all elements
5014 <tr>
5015 <td>Inherited:
5017 <td>yes
5019 <tr>
5020 <td>Percentages:
5022 <td>see individual properties
5024 <tr>
5025 <td>Media:
5027 <td>visual
5029 <tr>
5030 <td>Computed value:
5032 <td>see individual properties
5034 <tr>
5035 <td>Animatable:
5037 <td>see individual properties
5038 </table>
5040 <p>The value <dfn id=font-variant-normal-value
5041 title="normal!!font-variant">‘<code
5042 class=property>normal</code>’</dfn> resets all other font feature
5043 properties to their inital value. The <dfn id=font-variant-none-value
5044 title="none!!font-variant">‘<code class=property>none</code>’</dfn>
5045 value sets ‘<a href="#propdef-font-variant-ligatures"><code
5046 class=property>font-variant-ligatures</code></a>’ to ‘<code
5047 class=property>none</code>’ and resets all other font feature properties
5048 to their initial value. Like other shorthands, using <a
5049 href="#propdef-font-variant" title="font-variant!!property">‘<code
5050 class=property>font-variant</code>’</a> resets unspecified font-variant
5051 subproperties to their initial values. It does not reset the values of
5052 either ‘<a href="#propdef-font-language-override"><code
5053 class=property>font-language-override</code></a>’ or <span
5054 title="font-feature-settings!!property">‘<a
5055 href="#propdef-font-feature-settings"><code
5056 class=property>font-feature-settings</code></a>’</span>.
5058 <h3 id=font-feature-settings-prop><span class=secno>6.12 </span>Low-level
5059 font feature settings control: the <a
5060 href="#propdef-font-feature-settings">font-feature-settings</a> property</h3>
5062 <table class=propdef id=namefont-feature-settingsvaluenormal-ltf>
5063 <tbody>
5064 <tr>
5065 <td>Name:
5067 <td><dfn id=propdef-font-feature-settings>font-feature-settings</dfn>
5069 <tr>
5070 <td>Value:
5072 <td><a href="#font-feature-settings-normal-value"
5073 title="normal!!font-feature-settings">normal</a> | <a
5074 href="#feature-tag-value"><var><feature-tag-value></var></a> #
5076 <tr>
5077 <td>Initial:
5079 <td>normal
5081 <tr>
5082 <td>Applies to:
5084 <td>all elements
5086 <tr>
5087 <td>Inherited:
5089 <td>yes
5091 <tr>
5092 <td>Percentages:
5094 <td>N/A
5096 <tr>
5097 <td>Media:
5099 <td>visual
5101 <tr>
5102 <td>Computed value:
5104 <td>as specified
5106 <tr>
5107 <td>Animatable:
5109 <td>no
5110 </table>
5112 <p>This property provides low-level control over OpenType font features. It
5113 is intended as a way of providing access to font features that are not
5114 widely used but are needed for a particular use case. A value of <dfn
5115 id=font-feature-settings-normal-value
5116 title="normal!!font-feature-settings">‘<code
5117 class=property>normal</code>’</dfn> means that no change in glyph
5118 selection or positioning occurs due to this property.
5120 <p>
5122 <pre>/* enable small caps and use second swash alternate */
5123 font-feature-settings: "smcp", "swsh" 2;</pre>
5125 <p>Feature tag values have the following syntax:
5127 <pre
5128 class=prod><dfn id=feature-tag-value><var><feature-tag-value></var></dfn> = <string> [ <integer> | on | off ]?</pre>
5130 <p>The <string> is a case-sensitive OpenType feature tag. As
5131 specified in the OpenType specification, feature tags contain four ASCII
5132 characters. Tag strings longer or shorter than four characters, or
5133 containing characters outside the U+20–7E codepoint range are invalid.
5134 User agents must not use a feature tag created by truncating or padding
5135 the string to four characters. Feature tags need only match a feature tag
5136 defined in the font, they are not limited to explicitly registered
5137 OpenType features. Fonts defining custom feature tags should follow the <a
5138 href="http://www.microsoft.com/typography/otspec/featuretags.htm">tag name
5139 rules</a> defined in the OpenType specification <a
5140 href="#OPENTYPE-FEATURES"
5141 rel=biblioentry>[OPENTYPE-FEATURES]<!--{{!OPENTYPE-FEATURES}}--></a>.
5142 Feature tags not present in the font are ignored; a user agent must not
5143 attempt to synthesize fallback behavior based on these feature tags.
5145 <p>This means that explicitly disabling the <span class=tag>kern</span>
5146 feature will not affect the application of kerning data found in the
5147 ‘<code class=property>kern</code>’ table (as opposed to kerning data
5148 associated with the <span class=tag>kern</span> feature in the ‘<code
5149 class=property>GPOS</code>’ table). Authors should use the ‘<a
5150 href="#propdef-font-kerning"><code
5151 class=property>font-kerning</code></a>’ property to explictly enable or
5152 disable kerning since this property affects both types of kerning.
5154 <p>If present, a value indicates an index used for glyph selection. An
5155 <integer> value must be 0 or greater. A value of 0 indicates that
5156 the feature is disabled. For boolean features, a value of 1 enables the
5157 feature. For non-boolean features, a value of 1 or greater enables the
5158 feature and indicates the feature selection index. A value of ‘<code
5159 class=property>on</code>’ is synonymous with 1 and ‘<code
5160 class=property>off</code>’ is synonymous with 0. If the value is
5161 omitted, a value of 1 is assumed.
5163 <pre>
5164 font-feature-settings: "dlig" 1; /* dlig=1 enable discretionary ligatures */
5165 font-feature-settings: "smcp" on; /* smcp=1 enable small caps */
5166 font-feature-settings: 'c2sc'; /* c2sc=1 enable caps to small caps */
5167 font-feature-settings: "liga" off; /* liga=0 no common ligatures */
5168 font-feature-settings: "tnum", 'hist'; /* tnum=1, hist=1 enable tabular numbers and historical forms */
5169 font-feature-settings: "tnum" "hist"; /* invalid, need a comma-delimited list */
5170 font-feature-settings: "palin" off; /* good idea but invalid tagname */
5171 font-feature-settings: "PKRN"; /* PKRN=1 enable custom feature */
5172 font-feature-settings: dlig; /* invalid, tag must be a string */
5173 </pre>
5175 <p>When values greater than the range supported by the font are specified,
5176 the behavior is explicitly undefined. For boolean features, in general
5177 these will enable the feature. For non-boolean features, out of range
5178 values will in general be equivalent to a 0 value. However, in both cases
5179 the exact behavior will depend upon the way the font is designed
5180 (specifically, which type of lookup is used to define the feature).
5182 <p>Authors should generally use <a href="#propdef-font-variant"
5183 title="font-variant!!property">‘<code
5184 class=property>font-variant</code>’</a> and its related subproperties
5185 whenever possible and only use this property for special cases where its
5186 use is the only way of accessing a particular infrequently used font
5187 feature.
5189 <p>Although specifically defined for OpenType feature tags, feature tags
5190 for other modern font formats that support font features may be added in
5191 the future. Where possible, features defined for other font formats should
5192 attempt to follow the pattern of registered OpenType tags.
5194 <div class=example>
5195 <p>The Japanese text below will be rendered with half-width kana
5196 characters:</p>
5198 <pre lang=ja>
5199 body { font-feature-settings: "hwid"; /* Half-width OpenType feature */ }
5201 <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>
5202 </pre>
5203 </div>
5205 <h3 id=font-language-override-prop><span class=secno>6.13 </span>Font
5206 language override: the <a
5207 href="#propdef-font-language-override">font-language-override</a> property</h3>
5209 <table class=propdef id=namefont-language-overridevaluenormal-lt>
5210 <tbody>
5211 <tr>
5212 <td>Name:
5214 <td><dfn id=propdef-font-language-override>font-language-override</dfn>
5216 <tr>
5217 <td>Value:
5219 <td><a href="#font-language-override-normal-value"
5220 title="normal!!font-language-override">normal</a> | <a
5221 href="#font-language-override-string-value"><var><string></var></a>
5223 <tr>
5224 <td>Initial:
5226 <td><a href="#font-language-override-normal-value"
5227 title="normal!!font-language-override">normal</a>
5229 <tr>
5230 <td>Applies to:
5232 <td>all elements
5234 <tr>
5235 <td>Inherited:
5237 <td>yes
5239 <tr>
5240 <td>Percentages:
5242 <td>N/A
5244 <tr>
5245 <td>Media:
5247 <td>visual
5249 <tr>
5250 <td>Computed value:
5252 <td>as specified
5254 <tr>
5255 <td>Animatable:
5257 <td>no
5258 </table>
5260 <p>Normally, authors can control the use of language-specific glyph
5261 substitutions and positioning by setting the content language of an
5262 element, as <a href="#language-specific-support">described above</a>:
5264 <pre><!-- Display text using S'gaw Karen specific features -->
5265 <p lang="ksw">...</p></pre>
5267 <p>In some cases, authors may need to specify a language system that
5268 differs from the content language, for example due to the need to mimic
5269 another language's typographic traditions. The ‘<a
5270 href="#propdef-font-language-override"><code
5271 class=property>font-language-override</code></a>’ property allows
5272 authors to explicitly specify the language system of the font, overriding
5273 the language system implied by the content language.
5275 <p>Values have the following meanings:
5277 <dl>
5278 <dt><dfn id=font-language-override-normal-value
5279 title="normal!!font-language-override">normal</dfn>
5281 <dd>specifies that when rendering with OpenType fonts, the content
5282 language of the element is used to infer the OpenType language system
5284 <dt><dfn
5285 id=font-language-override-string-value><var><string></var></dfn>
5287 <dd>single three-letter OpenType <a
5288 href="http://www.microsoft.com/typography/otspec/languagetags.htm">language
5289 system tag</a>, specifies the OpenType language system to be used instead
5290 of the language system implied by the language of the element
5291 </dl>
5293 <div class=example>
5294 <p>The <a href="http://www.un.org/en/documents/udhr/index.shtml">Universal
5295 Declaration of Human Rights</a> has been translated into a wide variety
5296 of languages. In Turkish, Article 9 of this document might be marked up
5297 as below:</p>
5299 <pre lang=tr><body lang="tr">
5301 <h4>Madde 9</h4>
5302 <p>Hiç kimse keyfi olarak tutuklanamaz, alıkonulanamaz veya sürülemez.</p>
5303 </pre>
5305 <p>Here the user agent uses the value of the ‘<code
5306 class=property>lang</code>’ attribute when rendering text and
5307 appropriately renders this text without ‘<code
5308 class=property>fi</code>’ ligatures. There is no need to use the ‘<a
5309 href="#propdef-font-language-override"><code
5310 class=property>font-language-override</code></a>’ property.</p>
5312 <p>However, a given font may lack support for a specific language. In this
5313 situation authors may need to use the typographic conventions of a
5314 related language that are supported by that font:</p>
5316 <pre lang=mk><body lang="mk"> <!-- Macedonian lang code -->
5318 body { font-language-override: "SRB"; /* Serbian OpenType language tag */ }
5320 <h4>Члeн 9</h4>
5321 <p>Никoj чoвeк нeмa дa бидe пoдлoжeн нa прoизвoлнo aпсeњe, притвoр или прoгoнувaњe.</p>
5323 </pre>
5325 <p>The Macedonian text here will be rendered using Serbian typographic
5326 conventions, with the assumption that the font specified supports
5327 Serbian.</p>
5328 </div>
5330 <p><a id=rendering-considerations></a>
5332 <h2 id=font-feature-resolution><span class=secno>7 </span>Font Feature
5333 Resolution</h2>
5335 <p>As described in the previous section, font features can be enabled in a
5336 variety of ways, either via the use of <a href="#propdef-font-variant"
5337 title="font-variant!!property">‘<code
5338 class=property>font-variant</code>’</a> or <span
5339 title="font-feature-settings!!property">‘<a
5340 href="#propdef-font-feature-settings"><code
5341 class=property>font-feature-settings</code></a>’</span> in a style rule
5342 or within an <code>@font-face</code> rule. The resolution order for the
5343 union of these settings is defined below. Features defined via CSS
5344 properties are applied on top of layout engine default features.
5346 <h3 id=default-features><span class=secno>7.1 </span>Default features</h3>
5348 <p>For OpenType fonts, user agents must enable the default features defined
5349 in the OpenType documentation for a given script and writing mode.
5350 Required ligatures, common ligatures and contextual forms must be enabled
5351 by default (OpenType features: <span class=tag>rlig, liga, clig,
5352 calt</span>), along with localized forms (OpenType feature: <span
5353 class=tag>locl</span>), and features required for proper display of
5354 composed characters and marks (OpenType features: <span class=tag>ccmp,
5355 mark, mkmk</span>). These features must always be enabled, even when the
5356 value of the <a href="#propdef-font-variant"
5357 title="font-variant!!property">‘<code
5358 class=property>font-variant</code>’</a> and <span
5359 title="font-feature-settings!!property">‘<a
5360 href="#propdef-font-feature-settings"><code
5361 class=property>font-feature-settings</code></a>’</span> properties is
5362 ‘<code class=property>normal</code>’. Individual features are only
5363 disabled when explicitly overridden by the author, as when ‘<a
5364 href="#propdef-font-variant-ligatures"><code
5365 class=property>font-variant-ligatures</code></a>’ is set to ‘<a
5366 href="#no-common-ligatures"><code
5367 class=property>no-common-ligatures</code></a>’. For handling complex
5368 scripts such as <a
5369 href="http://www.microsoft.com/typography/otfntdev/arabicot/features.aspx">Arabic</a>,
5370 <a
5371 href="http://www.microsoft.com/typography/otfntdev/mongolot/features.htm">Mongolian</a>
5372 or <a
5373 href="http://www.microsoft.com/typography/otfntdev/devanot/features.aspx">Devanagari</a>
5374 additional features are required. For upright text within vertical text
5375 runs, vertical alternates (OpenType feature: <span class=tag>vert</span>)
5376 must be enabled.
5378 <h3 id=feature-precedence><span class=secno>7.2 </span>Feature precedence</h3>
5380 <p>General and font specific font feature property settings are resolved in
5381 the order below, in ascending precedence order. This ordering is used to
5382 construct a combined list of font features that affect a given text run.
5384 <ol>
5385 <li>Font features enabled by default, including features required for a
5386 given script.
5388 <li>If the font is defined via an <code>@font-face</code> rule, the font
5389 features implied by the font-variant descriptor in the
5390 <code>@font-face</code> rule.
5392 <li>If the font is defined via an <code>@font-face</code> rule, the font
5393 features implied by the font-feature-settings descriptor in the
5394 <code>@font-face</code> rule.
5396 <li>Feature settings determined by properties other than <a
5397 href="#propdef-font-variant" title="font-variant!!property">‘<code
5398 class=property>font-variant</code>’</a> or <span
5399 title="font-feature-settings!!property">‘<a
5400 href="#propdef-font-feature-settings"><code
5401 class=property>font-feature-settings</code></a>’</span>. For example,
5402 setting a non-default value for the ‘<code
5403 class=property>letter-spacing</code>’ property disables ligatures.
5405 <li>Font features implied by the value of the <a
5406 href="#propdef-font-variant" title="font-variant!!property">‘<code
5407 class=property>font-variant</code>’</a> property, the related
5408 font-variant subproperties and any other CSS property that may use
5409 OpenType features (e.g. the ‘<a href="#propdef-font-kerning"><code
5410 class=property>font-kerning</code></a>’ property).
5412 <li>Font features implied by the value of <span
5413 title="font-feature-settings!!property">‘<a
5414 href="#propdef-font-feature-settings"><code
5415 class=property>font-feature-settings</code></a>’</span> property.
5416 </ol>
5418 <p>This ordering allows authors to set up a general set of defaults for
5419 fonts within their <code>@font-face</code> rules, then override them with
5420 property settings for specific elements. General property settings
5421 override the settings in <code>@font-face</code> rules and low-level font
5422 feature settings override <a href="#propdef-font-variant"
5423 title="font-variant!!property">‘<code
5424 class=property>font-variant</code>’</a> property settings.
5426 <p>For situations where the combined list of font feature settings contains
5427 more than one value for the same feature, the last value is used. When a
5428 font lacks support for a given underlying font feature, text is simply
5429 rendered as if that font feature was not enabled; font fallback does not
5430 occur and no attempt is made to synthesize the feature except where
5431 explicitly noted for specific properties.
5433 <h3 id=feature-precedence-examples><span class=secno>7.3 </span>Feature
5434 precedence examples</h3>
5436 <div class=example>
5437 <p>With the styles below, numbers are rendered proportionally when used
5438 within a paragraph but are shown in tabular form within tables of prices:</p>
5440 <pre>body {
5441 font-variant-numeric: proportional-nums;
5442 }
5444 table.prices td {
5445 font-variant-numeric: tabular-nums;
5446 }
5447 </pre>
5448 </div>
5450 <div class=example>
5451 <p>When the font-variant descriptor is used within an
5452 <code>@font-face</code> rule, it only applies to the font defined by that
5453 rule.</p>
5455 <pre>@font-face {
5456 font-family: MainText;
5457 src: url(http://example.com/font.ttf);
5458 font-variant: oldstyle-nums proportional-nums styleset(1,3);
5459 }
5461 body {
5462 font-family: MainText, Helvetica;
5463 }
5465 table.prices td {
5466 font-variant-numeric: tabular-nums;
5467 }
5468 </pre>
5470 <p>In this case, old-style numerals will be used throughout but only where
5471 the font "MainText" is used. Just as in the previous example, tabular
5472 values will be used in price tables since ‘<a
5473 href="#tabular-nums"><code class=property>tabular-nums</code></a>’
5474 appears in a general style rule and its use is mutually exclusive with
5475 ‘<a href="#proportional-nums"><code
5476 class=property>proportional-nums</code></a>’. Stylistic alternate sets
5477 will only be used where MainText is used.</p>
5478 </div>
5480 <div class=example>
5481 <p>The <code>@font-face</code> rule can also be used to access font
5482 features in locally available fonts via the use of <code>local()</code>
5483 in the ‘<a href="#descdef-src"><code class=property>src</code></a>’
5484 descriptor of the <code>@font-face</code> definition:</p>
5486 <pre>@font-face {
5487 font-family: BodyText;
5488 src: local("HiraMaruPro-W4");
5489 font-variant: proportional-width;
5490 font-feature-settings: "ital"; /* Latin italics within CJK text feature */
5491 }
5493 body { font-family: BodyText, serif; }
5494 </pre>
5496 <p>If available, a Japanese font "Hiragino Maru Gothic" will be used. When
5497 text rendering occurs, Japanese kana will be proportionally spaced and
5498 Latin text will be italicised. Text rendered with the fallback serif font
5499 will use default rendering properties.</p>
5500 </div>
5502 <div class=example>
5503 <p>In the example below, discretionary ligatures are enabled only for a
5504 downloadable font but are disabled within spans of class "special":</p>
5506 <pre>@font-face {
5507 font-family: main;
5508 src: url(fonts/ffmeta.woff) format("woff");
5509 font-variant: discretionary-ligatures;
5510 }
5512 body { font-family: main, Helvetica; }
5513 span.special { font-variant-ligatures: no-discretionary-ligatures; }
5514 </pre>
5516 <p>Adding an discretionary style rule with the <code>@font-face</code>
5517 above:</p>
5519 <pre>body { font-family: main, Helvetica; }
5520 span { font-feature-settings: "dlig"; }
5521 span.special { font-variant-ligatures: no-discretionary-ligatures; }
5522 </pre>
5524 <p>Within spans of class "special", discretionary ligatures <em>will</em>
5525 be rendered. This is because both the <span
5526 title="font-feature-settings!!property">‘<a
5527 href="#propdef-font-feature-settings"><code
5528 class=property>font-feature-settings</code></a>’</span> and ‘<a
5529 href="#propdef-font-variant-ligatures"><code
5530 class=property>font-variant-ligatures</code></a>’ properties apply to
5531 these spans. Although the ‘<code class=css>no-discretionary
5532 ligatures</code>’ setting of ‘<a
5533 href="#propdef-font-variant-ligatures"><code
5534 class=property>font-variant-ligatures</code></a>’ effectively disables
5535 the OpenType <span class=tag>dlig</span> feature, because the <span
5536 title="font-feature-settings!!property">‘<a
5537 href="#propdef-font-feature-settings"><code
5538 class=property>font-feature-settings</code></a>’</span> is resolved
5539 after that, the ‘<code class=property>dlig</code>’ value reenables
5540 discretionary ligatures.</p>
5541 </div>
5543 <h2 id=object-model><span class=secno>8 </span>Object Model</h2>
5545 <p>The contents of <code>@font-face</code> and
5546 <code>@font-feature-values</code> rules can be accessed via the following
5547 extensions to the CSS Object Model.
5549 <h3 id=om-fontface><span class=secno>8.1 </span>The <a
5550 href="#cssfontfacerule"><code>CSSFontFaceRule</code></a> interface</h3>
5552 <p>The <dfn id=cssfontfacerule>CSSFontFaceRule</dfn> interface represents a
5553 <code>@font-face</code> rule.
5555 <pre class=idl>
5556 interface CSSFontFaceRule : CSSRule {
5557 attribute DOMString family;
5558 attribute DOMString src;
5559 attribute DOMString style;
5560 attribute DOMString weight;
5561 attribute DOMString stretch;
5562 attribute DOMString unicodeRange;
5563 attribute DOMString variant;
5564 attribute DOMString featureSettings;
5565 }</pre>
5567 <p>The DOM Level 2 Style specification <a href="#DOM-LEVEL-2-STYLE"
5568 rel=biblioentry>[DOM-LEVEL-2-STYLE]<!--{{DOM-LEVEL-2-STYLE}}--></a>
5569 defined a different variant of this rule. This definition supercedes that
5570 one.
5572 <h3 id=om-fontfeaturevalues><span class=secno>8.2 </span>The <a
5573 href="#cssfontfeaturevaluesrule"><code>CSSFontFeatureValuesRule</code></a>
5574 interface</h3>
5576 <p>The <code>CSSRule</code> interface is extended as follows:
5578 <pre class=idl>partial interface CSSRule {
5579 const unsigned short FONT_FEATURE_VALUES_RULE = 14;
5580 }</pre>
5582 <p>The <dfn id=cssfontfeaturevaluesrule>CSSFontFeatureValuesRule</dfn>
5583 interface represents a <code>@font-feature-values</code> rule.
5585 <pre class=idl>interface CSSFontFeatureValuesRule : CSSRule {
5586 readonly attribute DOMString familyList;
5587 readonly attribute DOMString valueText;
5588 };</pre>
5590 <dl class=idl-attributes>
5591 <dt><var>familyList</var> of type <code>DOMString</code>, readonly
5593 <dd>The list of one or more font families for which a given set of feature
5594 values is defined.
5596 <dt><var>valueText</var> of type <code>DOMString</code>, readonly
5598 <dd>Serialized set of feature values.
5599 </dl>
5601 <h2 class=no-num id=platform-props-to-css>Appendix A: Mapping platform font
5602 properties to CSS properties</h2>
5604 <p><em>This appendix is included as background for some of the problems and
5605 situations that are described in other sections. It should be viewed as
5606 informative only.</em>
5608 <p>Font properties in CSS are designed to be independent of the underlying
5609 font formats used; they can be used to specify bitmap fonts, Type1 fonts,
5610 SVG fonts in addition to the common TrueType and OpenType fonts. But there
5611 are facets of the TrueType and OpenType formats that often cause confusion
5612 for authors and present challenges to implementers on different platforms.
5614 <p>Originally developed at Apple, TrueType was designed as an outline font
5615 format for both screen and print. Microsoft joined Apple in developing the
5616 TrueType format and both platforms have supported TrueType fonts since
5617 then. Font data in the TrueType format consists of a set of tables
5618 distinguished with common four-letter tag names, each containing a
5619 specific type of data. For example, naming information, including
5620 copyright and license information, is stored in the ‘<code
5621 class=property>name</code>’ table. The <a
5622 href="#character-map"><em>character map</em></a> (‘<code
5623 class=property>cmap</code>’) table contains a mapping of character
5624 encodings to glyphs. Apple later added additional tables for supporting
5625 enhanced typographic functionality; these are now called Apple Advanced
5626 Typography, or AAT, fonts. Microsoft and Adobe developed a separate set of
5627 tables for advanced typography and called their format OpenType <a
5628 href="#OPENTYPE" rel=biblioentry>[OPENTYPE]<!--{{!OPENTYPE}}--></a>.
5630 <p>In many cases the font data used under Microsoft Windows or Linux is
5631 slightly different from the data used under Apple's Mac OS X because the
5632 TrueType format allowed for explicit variation across platforms. This
5633 includes font metrics, names and <a href="#character-map"><em>character
5634 map</em></a> data.
5636 <p>Specifically, font family name data is handled differently across
5637 platforms. For TrueType and OpenType fonts these names are contained in
5638 the ‘<code class=property>name</code>’ table, in name records with
5639 name ID 1. Mulitple names can be stored for different locales, but
5640 Microsoft recommends fonts always include at least a US English version of
5641 the name. On Windows, Microsoft made the decision for backwards
5642 compatibility to limit this family name to a maximum of four faces; for
5643 larger groupings the "preferred family" (name ID 16) or "WWS family" (name
5644 ID 21) can be used. Other platforms such as OSX don't have this
5645 limitation, so the family name is used to define all possible groupings.
5647 <p>Other name table data provides names used to uniquely identify a
5648 specific face within a family. The full font name (name ID 4) and the
5649 Postscript name (name ID 6) describe a single face uniquely. For example,
5650 the bold face of the Gill Sans family has a fullname of "Gill Sans Bold"
5651 and a Postscript name of "GillSans-Bold". There can be multiple localized
5652 versions of the fullname for a given face, but the Postscript name is
5653 always a unique name made from a limited set of ASCII characters.
5655 <p>On various platforms, different names are used to search for a font. For
5656 example, with the Windows GDI CreateIndirectFont API, either a family or
5657 fullname can be used to lookup a face, while on Mac OS X the
5658 CTFontCreateWithName API call is used to lookup a given face using the
5659 fullname and Postscript name. Under Linux, the fontconfig API allows fonts
5660 to be searched using any of these names. In situations where platform
5661 API's automatically substitute other font choices, it may be necessary to
5662 verify a returned font matches a given name.
5664 <p>The weight of a given face can be determined via the usWeightClass field
5665 of the OS/2 table or inferred from the style name (name ID 2). Likewise,
5666 the width can be determined via the usWidthClass of the OS/2 table or
5667 inferred from the style name. For historical reasons related to synthetic
5668 bolding at weights 200 or lower with the Windows GDI API, font designers
5669 have sometimes skewed values in the OS/2 table to avoid these weights.
5671 <p>Rendering complex scripts that use contextual shaping such as Thai,
5672 Arabic and Devanagari requires features present only in OpenType or AAT
5673 fonts. Currently, complex script rendering is supported on Windows and
5674 Linux using OpenType font features while both OpenType and AAT font
5675 features are used under Mac OS X.
5677 <h2 class=no-num id=ch-ch-ch-changes>Changes</h2>
5679 <h3 class=no-num id=recent-changes> Changes from the <a
5680 href="http://www.w3.org/TR/2013/WD-css3-fonts-20130212/">February 2013
5681 CSS3 Fonts Working Draft</a></h3>
5683 <p>Major changes include:
5685 <ul>
5686 <li>Moved font load events into a separate <a
5687 href="http://dev.w3.org/csswg/css3-font-load-events/">spec</a>
5689 <li>Tightened error handling rules for <code>@font-feature-values</code>
5690 rules
5692 <li>Added grammar productions for <code>@font-face</code> and
5693 <code>@font-feature-values</code> rules
5695 <li>Tightened definition of synthetic oblique
5697 <li>Revised definition of ‘<a href="#descdef-unicode-range"><code
5698 class=property>unicode-range</code></a>’ descriptor
5699 </ul>
5701 <h2 class=no-num id=acknowledgments>Acknowledgments</h2>
5703 <p>I'd like to thank Tal Leming, Jonathan Kew and Christopher Slye for all
5704 their help and feedback. John Hudson was kind enough to take the time to
5705 explain the subtleties of OpenType language tags and provided the example
5706 of character variant usage for displaying text on Byzantine seals. Ken
5707 Lunde and Eric Muller provided valuable feedback on CJK OpenType features
5708 and Unicode variation selectors. The idea for supporting font features by
5709 using font-variant subproperties originated with Håkon Wium Lie, Adam
5710 Twardoch and Tal Leming. Elika Etemad supplied some of the initial design
5711 ideas for the <code>@font-feature-values</code> rule. Thanks also to House
5712 Industries for allowing the use of Ed Interlock in the discretionary
5713 ligatures example.
5715 <p>A special thanks to Robert Bringhurst for the sublime mind expansion
5716 that is <em>The Elements of Typographic Style</em>.
5718 <h2 class=no-num id=conformance> Conformance</h2>
5720 <h3 class=no-num id=conventions> Document Conventions</h3>
5722 <p>Conformance requirements are expressed with a combination of descriptive
5723 assertions and RFC 2119 terminology. The key words “MUST”, “MUST
5724 NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”,
5725 “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in the
5726 normative parts of this document are to be interpreted as described in RFC
5727 2119. However, for readability, these words do not appear in all uppercase
5728 letters in this specification.
5730 <p>All of the text of this specification is normative except sections
5731 explicitly marked as non-normative, examples, and notes. <a
5732 href="#RFC2119" rel=biblioentry>[RFC2119]<!--{{!RFC2119}}--></a>
5734 <p>Examples in this specification are introduced with the words “for
5735 example” or are set apart from the normative text with
5736 <code>class="example"</code>, like this:
5738 <div class=example>
5739 <p>This is an example of an informative example.
5740 </div>
5742 <p>Informative notes begin with the word “Note” and are set apart from
5743 the normative text with <code>class="note"</code>, like this:
5745 <p class=note>Note, this is an informative note.
5747 <h3 class=no-num id=conformance-classes> Conformance Classes</h3>
5749 <p>Conformance to CSS Fonts Level 3 Module is defined for three conformance
5750 classes:
5752 <dl>
5753 <dt><dfn id=style-sheet title="style sheet!!as conformance class">style
5754 sheet</dfn>
5756 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
5757 style sheet</a>.
5759 <dt><dfn id=renderer>renderer</dfn>
5761 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
5762 that interprets the semantics of a style sheet and renders documents that
5763 use them.
5765 <dt><dfn id=authoring-tool>authoring tool</dfn>
5767 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
5768 that writes a style sheet.
5769 </dl>
5771 <p>A style sheet is conformant to CSS Fonts Level 3 Module if all of its
5772 declarations that use properties defined in this module have values that
5773 are valid according to the generic CSS grammar and the individual grammars
5774 of each property as given in this module.
5776 <p>A renderer is conformant to CSS Fonts Level 3 Module if, in addition to
5777 interpreting the style sheet as defined by the appropriate specifications,
5778 it supports all the features defined by CSS Fonts Level 3 Module by
5779 parsing them correctly and rendering the document accordingly. However,
5780 the inability of a UA to correctly render a document due to limitations of
5781 the device does not make the UA non-conformant. (For example, a UA is not
5782 required to render color on a monochrome monitor.)
5784 <p>An authoring tool is conformant to CSS Fonts Level 3 Module if it writes
5785 style sheets that are syntactically correct according to the generic CSS
5786 grammar and the individual grammars of each feature in this module, and
5787 meet all other conformance requirements of style sheets as described in
5788 this module.
5790 <h3 class=no-num id=partial> Partial Implementations</h3>
5792 <p>So that authors can exploit the forward-compatible parsing rules to
5793 assign fallback values, CSS renderers <strong>must</strong> treat as
5794 invalid (and <a
5795 href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore as
5796 appropriate</a>) any at-rules, properties, property values, keywords, and
5797 other syntactic constructs for which they have no usable level of support.
5798 In particular, user agents <strong>must not</strong> selectively ignore
5799 unsupported component values and honor supported values in a single
5800 multi-value property declaration: if any value is considered invalid (as
5801 unsupported values must be), CSS requires that the entire declaration be
5802 ignored.
5804 <h3 class=no-num id=experimental> Experimental Implementations</h3>
5806 <p>To avoid clashes with future CSS features, the CSS2.1 specification
5807 reserves a <a
5808 href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
5809 syntax</a> for proprietary and experimental extensions to CSS.
5811 <p>Prior to a specification reaching the Candidate Recommendation stage in
5812 the W3C process, all implementations of a CSS feature are considered
5813 experimental. The CSS Working Group recommends that implementations use a
5814 vendor-prefixed syntax for such features, including those in W3C Working
5815 Drafts. This avoids incompatibilities with future changes in the draft.
5817 <h3 class=no-num id=testing> Non-Experimental Implementations</h3>
5819 <p>Once a specification reaches the Candidate Recommendation stage,
5820 non-experimental implementations are possible, and implementors should
5821 release an unprefixed implementation of any CR-level feature they can
5822 demonstrate to be correctly implemented according to spec.
5824 <p>To establish and maintain the interoperability of CSS across
5825 implementations, the CSS Working Group requests that non-experimental CSS
5826 renderers submit an implementation report (and, if necessary, the
5827 testcases used for that implementation report) to the W3C before releasing
5828 an unprefixed implementation of any CSS features. Testcases submitted to
5829 W3C are subject to review and correction by the CSS Working Group.
5831 <p>Further information on submitting testcases and implementation reports
5832 can be found from on the CSS Working Group's website at <a
5833 href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
5834 Questions should be directed to the <a
5835 href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
5836 mailing list.
5838 <h2 class=no-num id=references>References</h2>
5840 <h3 class=no-num id=normative-references>Normative References</h3>
5841 <!--begin-normative-->
5842 <!-- Sorted by label -->
5844 <dl class=bibliography>
5845 <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
5846 <!---->
5848 <dt id=CHARMOD>[CHARMOD]
5850 <dd>Martin J. Dürst; et al. <a
5851 href="http://www.w3.org/TR/2005/REC-charmod-20050215/"><cite>Character
5852 Model for the World Wide Web 1.0: Fundamentals.</cite></a> 15 February
5853 2005. W3C Recommendation. URL: <a
5854 href="http://www.w3.org/TR/2005/REC-charmod-20050215/">http://www.w3.org/TR/2005/REC-charmod-20050215/</a>
5855 </dd>
5856 <!---->
5858 <dt id=CORS>[CORS]
5860 <dd>Anne van Kesteren. <a
5861 href="http://www.w3.org/TR/2013/CR-cors-20130129/"><cite>Cross-Origin
5862 Resource Sharing.</cite></a> 29 January 2013. W3C Candidate
5863 Recommendation. (Work in progress.) URL: <a
5864 href="http://www.w3.org/TR/2013/CR-cors-20130129/">http://www.w3.org/TR/2013/CR-cors-20130129/</a>
5865 </dd>
5866 <!---->
5868 <dt id=CSS21>[CSS21]
5870 <dd>Bert Bos; et al. <a
5871 href="http://www.w3.org/TR/2011/REC-CSS2-20110607"><cite>Cascading Style
5872 Sheets Level 2 Revision 1 (CSS 2.1) Specification.</cite></a> 7 June
5873 2011. W3C Recommendation. URL: <a
5874 href="http://www.w3.org/TR/2011/REC-CSS2-20110607">http://www.w3.org/TR/2011/REC-CSS2-20110607</a>
5875 </dd>
5876 <!---->
5878 <dt id=CSS3VAL>[CSS3VAL]
5880 <dd>Håkon Wium Lie; Tab Atkins; Elika J. Etemad. <a
5881 href="http://www.w3.org/TR/2012/CR-css3-values-20120828/"><cite>CSS
5882 Values and Units Module Level 3.</cite></a> 28 August 2012. W3C Candidate
5883 Recommendation. (Work in progress.) URL: <a
5884 href="http://www.w3.org/TR/2012/CR-css3-values-20120828/">http://www.w3.org/TR/2012/CR-css3-values-20120828/</a>
5885 </dd>
5886 <!---->
5888 <dt id=HTML5>[HTML5]
5890 <dd>Ian Hickson. <a
5891 href="http://www.w3.org/TR/2012/CR-html5-20121217/"><cite>HTML5.</cite></a>
5892 17 December 2012. W3C Candidate Recommendation. (Work in progress.) URL:
5893 <a
5894 href="http://www.w3.org/TR/2012/CR-html5-20121217/">http://www.w3.org/TR/2012/CR-html5-20121217/</a>
5895 </dd>
5896 <!---->
5898 <dt id=OPEN-FONT-FORMAT>[OPEN-FONT-FORMAT]
5900 <dd><a
5901 href="http://standards.iso.org/ittf/PubliclyAvailableStandards/c052136_ISO_IEC_14496-22_2009(E).zip"><cite>Information
5902 technology — Coding of audio-visual objects — Part 22: Open Font
5903 Format.</cite></a> International Organization for Standardization.
5904 ISO/IEC 14496-22:2009. URL: <a
5905 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>
5906 </dd>
5907 <!---->
5909 <dt id=OPENTYPE>[OPENTYPE]
5911 <dd><a
5912 href="http://www.microsoft.com/typography/otspec/default.htm"><cite>OpenType
5913 specification.</cite></a> Microsoft. URL: <a
5914 href="http://www.microsoft.com/typography/otspec/default.htm">http://www.microsoft.com/typography/otspec/default.htm</a>
5915 </dd>
5916 <!---->
5918 <dt id=OPENTYPE-FEATURES>[OPENTYPE-FEATURES]
5920 <dd><a
5921 href="http://www.microsoft.com/typography/otspec/featurelist.htm"><cite>OpenType
5922 feature registry.</cite></a> Microsoft. URL: <a
5923 href="http://www.microsoft.com/typography/otspec/featurelist.htm">http://www.microsoft.com/typography/otspec/featurelist.htm</a>
5924 </dd>
5925 <!---->
5927 <dt id=RFC2119>[RFC2119]
5929 <dd>S. Bradner. <a href="http://www.ietf.org/rfc/rfc2119.txt"><cite>Key
5930 words for use in RFCs to Indicate Requirement Levels.</cite></a> Internet
5931 RFC 2119. URL: <a
5932 href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a>
5933 </dd>
5934 <!---->
5936 <dt id=UAX15>[UAX15]
5938 <dd>Mark Davis; Ken Whistler. <a
5939 href="http://www.unicode.org/reports/tr15/"><cite>Unicode Normalization
5940 Forms.</cite></a> 31 August 2012. Unicode Standard Annex #15. URL: <a
5941 href="http://www.unicode.org/reports/tr15/">http://www.unicode.org/reports/tr15/</a>
5942 </dd>
5943 <!---->
5945 <dt id=UAX29>[UAX29]
5947 <dd>Mark Davis. <a
5948 href="http://www.unicode.org/reports/tr29/"><cite>Unicode Text
5949 Segmentation.</cite></a> 12 September 2012. Unicode Standard Annex #29.
5950 URL: <a
5951 href="http://www.unicode.org/reports/tr29/">http://www.unicode.org/reports/tr29/</a>
5952 </dd>
5953 <!---->
5955 <dt id=UNICODE6>[UNICODE6]
5957 <dd>The Unicode Consortium. <a
5958 href="http://www.unicode.org/versions/Unicode6.2.0/"><cite>The Unicode
5959 Standard, Version 6.2.0.</cite></a> Defined by: The Unicode Standard,
5960 Version 6.2.0 URL: <a
5961 href="http://www.unicode.org/versions/Unicode6.2.0/">http://www.unicode.org/versions/Unicode6.2.0/</a>
5962 </dd>
5963 <!---->
5964 </dl>
5965 <!--end-normative-->
5966 <!--{{!CSS21}}-->
5967 <!--{{!CSS3VAL}}-->
5968 <!--{{!OPENTYPE}}-->
5969 <!--{{!OPENTYPE-FEATURES}}-->
5970 <!--{{!OPEN-FONT-FORMAT}}-->
5971 <!--{{!UNICODE6}}-->
5972 <!--{{!UAX15}}-->
5973 <!--{{!UAX29}}-->
5974 <!--{{!CORS}}-->
5975 <!--{{!HTML5}}-->
5976 <!--{{!CHARMOD}}-->
5978 <h3 class=no-num id=other-references>Other References</h3>
5979 <!--begin-informative-->
5980 <!-- Sorted by label -->
5982 <dl class=bibliography>
5983 <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
5984 <!---->
5986 <dt id=AAT-FEATURES>[AAT-FEATURES]
5988 <dd><a href="http://developer.apple.com/fonts/registry/"><cite>Apple
5989 Advanced Typography font feature registry.</cite></a> Apple. URL: <a
5990 href="http://developer.apple.com/fonts/registry/">http://developer.apple.com/fonts/registry/</a>
5991 </dd>
5992 <!---->
5994 <dt id=ARABIC-TYPO>[ARABIC-TYPO]
5996 <dd>Huda Smitshuijzen AbiFares. <cite>Arabic Typography: A Comprehensive
5997 Sourcebook.</cite> Saqi Books. 2001. ISBN 0-86356-347-3.</dd>
5998 <!---->
6000 <dt id=CHARMOD-NORM>[CHARMOD-NORM]
6002 <dd>François Yergeau; et al. <a
6003 href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/"><cite>Character
6004 Model for the World Wide Web 1.0: Normalization.</cite></a> 1 May 2012.
6005 W3C Working Draft. (Work in progress.) URL: <a
6006 href="http://www.w3.org/TR/2012/WD-charmod-norm-20120501/">http://www.w3.org/TR/2012/WD-charmod-norm-20120501/</a>
6007 </dd>
6008 <!---->
6010 <dt id=CJKV-INFO-PROCESSING>[CJKV-INFO-PROCESSING]
6012 <dd>Ken Lunde. <cite>CJKV Information Processing, Second Edition.</cite>
6013 O'Reilly Media, Inc. 2009. ISBN 0-596-51447-1.</dd>
6014 <!---->
6016 <dt id=CSS3-CONDITIONAL>[CSS3-CONDITIONAL]
6018 <dd>L. David Baron. <a
6019 href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/"><cite>CSS
6020 Conditional Rules Module Level 3.</cite></a> 13 December 2012. W3C
6021 Working Draft. (Work in progress.) URL: <a
6022 href="http://www.w3.org/TR/2012/WD-css3-conditional-20121213/">http://www.w3.org/TR/2012/WD-css3-conditional-20121213/</a>
6023 </dd>
6024 <!---->
6026 <dt id=CSS3TEXT>[CSS3TEXT]
6028 <dd>Elika J. Etemad; Koji Ishii. <a
6029 href="http://www.w3.org/TR/2012/WD-css3-text-20121113/"><cite>CSS Text
6030 Module Level 3.</cite></a> 13 November 2012. W3C Working Draft. (Work in
6031 progress.) URL: <a
6032 href="http://www.w3.org/TR/2012/WD-css3-text-20121113/">http://www.w3.org/TR/2012/WD-css3-text-20121113/</a>
6033 </dd>
6034 <!---->
6036 <dt id=DIGITAL-TYPOGRAPHY>[DIGITAL-TYPOGRAPHY]
6038 <dd>Richard Rubinstein. <cite>Digital Typography, An Introduction to Type
6039 and Composition for Computer System Design.</cite> Addison-Wesley. 1988.
6040 ISBN 0-201-17633-5.</dd>
6041 <!---->
6043 <dt id=DOM-LEVEL-2-STYLE>[DOM-LEVEL-2-STYLE]
6045 <dd>Chris Wilson; Philippe Le Hégaret; Vidur Apparao. <a
6046 href="http://www.w3.org/TR/2000/REC-DOM-Level-2-Style-20001113/"><cite>Document
6047 Object Model (DOM) Level 2 Style Specification.</cite></a> 13 November
6048 2000. W3C Recommendation. URL: <a
6049 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>
6050 </dd>
6051 <!---->
6053 <dt id=ELEMTYPO>[ELEMTYPO]
6055 <dd>Robert Bringhurst. <cite>The Elements of Typographic Style, Version
6056 4.</cite> Hartley & Marks. 2013. ISBN 0-88179-212-8.</dd>
6057 <!---->
6059 <dt id=LANGCULTTYPE>[LANGCULTTYPE]
6061 <dd>John D. Berry, Ed. <cite>Language Culture Type.</cite> Graphis. 2001.
6062 ISBN 1-932026-01-0.</dd>
6063 <!---->
6065 <dt id=OPENTYPE-FONT-GUIDE>[OPENTYPE-FONT-GUIDE]
6067 <dd><a
6068 href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf"><cite>OpenType
6069 User Guide.</cite></a> FontShop International. URL: <a
6070 href="https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf">https://www.fontfont.com/staticcontent/downloads/FF_OT_User_Guide.pdf</a>
6071 </dd>
6072 <!---->
6074 <dt id=RASTER-TRAGEDY>[RASTER-TRAGEDY]
6076 <dd>Beat Stamm. <a href="http://www.rastertragedy.com/"><cite>The Raster
6077 Tragedy at Low-Resolution Revisited.</cite></a> 7 December 2011. URL: <a
6078 href="http://www.rastertragedy.com/">http://www.rastertragedy.com/</a></dd>
6079 <!---->
6081 <dt id=WINDOWS-GLYPH-PROC>[WINDOWS-GLYPH-PROC]
6083 <dd>John Hudson. <a
6084 href="http://www.microsoft.com/typography/developers/opentype/default.htm"><cite>Windows
6085 Glyph Processing.</cite></a> Microsoft Typogrraphy. URL: <a
6086 href="http://www.microsoft.com/typography/developers/opentype/default.htm">http://www.microsoft.com/typography/developers/opentype/default.htm</a>
6087 </dd>
6088 <!---->
6089 </dl>
6090 <!--end-informative-->
6091 <!--{{ARABIC-TYPO}}-->
6092 <!--{{CJKV-INFO-PROCESSING}}-->
6093 <!--{{DIGITAL-TYPOGRAPHY}}-->
6094 <!--{{DOM-LEVEL-2-STYLE}}-->
6095 <!--{{ELEMTYPO}}-->
6096 <!--{{LANGCULTTYPE}}-->
6097 <!--{{OPENTYPE-FONT-GUIDE}}-->
6098 <!--{{RASTER-TRAGEDY}}-->
6099 <!--{{WINDOWS-GLYPH-PROC}}-->
6100 <!--{{CHARMOD-NORM}}-->
6101 <!--{{AAT-FEATURES}}-->
6102 <!--{{CSS3-CONDITIONAL}}-->
6103 <!--{{CSS3TEXT}}-->
6105 <h2 class=no-num id=index>Index</h2>
6106 <!--begin-index-->
6108 <ul class=indexlist>
6109 <li>100...900 weight values, <a href="#font-weight-numeric-values"
6110 title="100...900 weight values"><strong>3.2</strong></a>
6112 <li><var><absolute-size></var>, <a href="#absolute-size-value"
6113 title="<absolute-size>"><strong>3.5</strong></a>
6115 <li><var><common-lig-values></var>, <a href="#common-lig-values"
6116 title="<common-lig-values>"><strong>6.4</strong></a>
6118 <li><var><contextual-alt-values></var>, <a
6119 href="#contextual-alt-values"
6120 title="<contextual-alt-values>"><strong>6.4</strong></a>
6122 <li><var><discretionary-lig-values></var>, <a
6123 href="#discretionary-lig-values"
6124 title="<discretionary-lig-values>"><strong>6.4</strong></a>
6126 <li><var><east-asian-variant-values></var>, <a
6127 href="#east-asian-variant-values"
6128 title="<east-asian-variant-values>"><strong>6.10</strong></a>
6130 <li><var><east-asian-width-values></var>, <a
6131 href="#east-asian-width-values"
6132 title="<east-asian-width-values>"><strong>6.10</strong></a>
6134 <li><var><family-name></var>, <a href="#family-name-value"
6135 title="<family-name>"><strong>3.1</strong></a>
6137 <li><var><feature-tag-value></var>, <a href="#feature-tag-value"
6138 title="<feature-tag-value>"><strong>6.12</strong></a>
6140 <li><var><font-face-name></var>, <a href="#font-face-name-value"
6141 title="<font-face-name>"><strong>4.3</strong></a>
6143 <li><var><font-variant-css21></var>, <a
6144 href="#font-variant-css21-values"
6145 title="<font-variant-css21>"><strong>3.7</strong></a>
6147 <li><var><generic-family></var>, <a href="#generic-family-value"
6148 title="<generic-family>"><strong>3.1</strong></a>
6150 <li><var><historical-lig-values></var>, <a
6151 href="#historical-lig-values"
6152 title="<historical-lig-values>"><strong>6.4</strong></a>
6154 <li><var><length></var>, <a href="#length-size-value"
6155 title="<length>"><strong>3.5</strong></a>
6157 <li><var><number></var>, <a href="#aspect-ratio-value"
6158 title="<number>"><strong>3.6</strong></a>
6160 <li><var><numeric-figure-values></var>, <a
6161 href="#numeric-figure-values"
6162 title="<numeric-figure-values>"><strong>6.7</strong></a>
6164 <li><var><numeric-fraction-values></var>, <a
6165 href="#numeric-fraction-values"
6166 title="<numeric-fraction-values>"><strong>6.7</strong></a>
6168 <li><var><numeric-spacing-values></var>, <a
6169 href="#numeric-spacing-values"
6170 title="<numeric-spacing-values>"><strong>6.7</strong></a>
6172 <li><var><percentage></var>, <a href="#percentage-size-value"
6173 title="<percentage>"><strong>3.5</strong></a>
6175 <li><var><relative-size></var>, <a href="#relative-size-value"
6176 title="<relative-size>"><strong>3.5</strong></a>
6178 <li><var><string></var>, <a
6179 href="#font-language-override-string-value"
6180 title="<string>"><strong>6.13</strong></a>
6182 <li><var><urange></var>, <a href="#urange-value"
6183 title="<urange>"><strong>4.5</strong></a>
6185 <li>@font-face, <a href="#font-face" title="@font-face">4.1</a>, <a
6186 href="#font-face0" title="@font-face">4.3</a>
6188 <li>all-petite-caps, <a href="#all-petite-caps"
6189 title=all-petite-caps><strong>6.6</strong></a>
6191 <li>all-small-caps, <a href="#all-small-caps"
6192 title=all-small-caps><strong>6.6</strong></a>
6194 <li>annotation, <a href="#annotation"
6195 title=annotation><strong>6.8</strong></a>
6197 <li>aspect value, <a href="#aspect-value0" title="aspect
6198 value"><strong>3.6</strong></a>
6200 <li>authoring tool, <a href="#authoring-tool" title="authoring
6201 tool"><strong>#</strong></a>
6203 <li>auto
6204 <ul>
6205 <li>font-kerning, <a href="#font-kerning-auto-value" title="auto,
6206 font-kerning"><strong>6.3</strong></a>
6208 <li>font-size-adjust, <a href="#font-size-adjust-auto-value"
6209 title="auto, font-size-adjust"><strong>3.6</strong></a>
6210 </ul>
6212 <li>bold, <a href="#bold" title=bold><strong>3.2</strong></a>
6214 <li>bolder, <a href="#bolder" title=bolder><strong>3.2</strong></a>
6216 <li>character map, <a href="#character-map" title="character
6217 map"><strong>5.2</strong></a>
6219 <li>character-variant, <a href="#character-variant"
6220 title=character-variant><strong>6.8</strong></a>
6222 <li>common-ligatures, <a href="#common-ligatures"
6223 title=common-ligatures><strong>6.4</strong></a>
6225 <li>condensed, <a href="#condensed"
6226 title=condensed><strong>3.3</strong></a>
6228 <li>contextual, <a href="#contextual"
6229 title=contextual><strong>6.4</strong></a>
6231 <li>CSSFontFaceRule, <a href="#cssfontfacerule"
6232 title=CSSFontFaceRule><strong>8.1</strong></a>
6234 <li>CSSFontFeatureValuesRule, <a href="#cssfontfeaturevaluesrule"
6235 title=CSSFontFeatureValuesRule><strong>8.2</strong></a>
6237 <li>cursive, definition of, <a href="#cursive0" title="cursive, definition
6238 of"><strong>#</strong></a>
6240 <li>default face, <a href="#default-face" title="default
6241 face"><strong>5.2</strong></a>
6243 <li>descriptor_declaration, <a href="#descriptordeclaration"
6244 title="descriptor_declaration"><strong>4.1</strong></a>
6246 <li>diagonal-fractions, <a href="#diagonal-fractions"
6247 title=diagonal-fractions><strong>6.7</strong></a>
6249 <li>discretionary-ligatures, <a href="#discretionary-ligatures"
6250 title=discretionary-ligatures><strong>6.4</strong></a>
6252 <li>expanded, <a href="#expanded" title=expanded><strong>3.3</strong></a>
6254 <li>extra-condensed, <a href="#extra-condensed"
6255 title=extra-condensed><strong>3.3</strong></a>
6257 <li>extra-expanded, <a href="#extra-expanded"
6258 title=extra-expanded><strong>3.3</strong></a>
6260 <li>fantasy, definition of, <a href="#fantasy0" title="fantasy, definition
6261 of"><strong>#</strong></a>
6263 <li>feature_type, <a href="#featuretype"
6264 title="feature_type"><strong>6.9</strong></a>
6266 <li>feature_value_block, <a href="#featurevalueblock"
6267 title="feature_value_block"><strong>6.9</strong></a>
6269 <li>feature_value_definition, <a href="#featurevaluedefinition"
6270 title="feature_value_definition"><strong>6.9</strong></a>
6272 <li>font, <a href="#propdef-font" title=font><strong>3.7</strong></a>
6274 <li>font-family
6275 <ul>
6276 <li>descriptor, <a href="#descdef-font-family" title="font-family,
6277 descriptor"><strong>4.2</strong></a>
6279 <li>property, <a href="#propdef-font-family" title="font-family,
6280 property"><strong>3.1</strong></a>
6281 </ul>
6283 <li>font-feature-settings, <a href="#propdef-font-feature-settings"
6284 title=font-feature-settings><strong>6.12</strong></a>
6285 <ul>
6286 <li>descriptor, <a href="#descdef-font-feature-settings"
6287 title="font-feature-settings, descriptor"><strong>4.7</strong></a>
6288 </ul>
6290 <li>font-kerning, <a href="#propdef-font-kerning"
6291 title=font-kerning><strong>6.3</strong></a>
6293 <li>font-language-override, <a href="#propdef-font-language-override"
6294 title=font-language-override><strong>6.13</strong></a>
6296 <li>font-size, <a href="#propdef-font-size"
6297 title=font-size><strong>3.5</strong></a>
6299 <li>font-size-adjust, <a href="#propdef-font-size-adjust"
6300 title=font-size-adjust><strong>3.6</strong></a>
6302 <li>font-stretch
6303 <ul>
6304 <li>descriptor, <a href="#descdef-font-stretch" title="font-stretch,
6305 descriptor"><strong>4.4</strong></a>
6307 <li>property, <a href="#propdef-font-stretch" title="font-stretch,
6308 property"><strong>3.3</strong></a>
6309 </ul>
6311 <li>font-style
6312 <ul>
6313 <li>descriptor, <a href="#descdef-font-style" title="font-style,
6314 descriptor"><strong>4.4</strong></a>
6316 <li>property, <a href="#propdef-font-style" title="font-style,
6317 property"><strong>3.4</strong></a>
6318 </ul>
6320 <li>font-synthesis, <a href="#propdef-font-synthesis"
6321 title=font-synthesis><strong>3.8</strong></a>
6323 <li>font-variant
6324 <ul>
6325 <li>descriptor, <a href="#descdef-font-variant" title="font-variant,
6326 descriptor"><strong>4.7</strong></a>
6328 <li>property, <a href="#propdef-font-variant" title="font-variant,
6329 property"><strong>6.11</strong></a>
6330 </ul>
6332 <li>font-variant-alternates, <a href="#propdef-font-variant-alternates"
6333 title=font-variant-alternates><strong>6.8</strong></a>
6335 <li>font-variant-caps, <a href="#propdef-font-variant-caps"
6336 title=font-variant-caps><strong>6.6</strong></a>
6338 <li>font-variant-east-asian, <a href="#propdef-font-variant-east-asian"
6339 title=font-variant-east-asian><strong>6.10</strong></a>
6341 <li>font-variant-ligatures, <a href="#propdef-font-variant-ligatures"
6342 title=font-variant-ligatures><strong>6.4</strong></a>
6344 <li>font-variant-numeric, <a href="#propdef-font-variant-numeric"
6345 title=font-variant-numeric><strong>6.7</strong></a>
6347 <li>font-variant-position, <a href="#propdef-font-variant-position"
6348 title=font-variant-position><strong>6.5</strong></a>
6350 <li>font-weight
6351 <ul>
6352 <li>descriptor, <a href="#descdef-font-weight" title="font-weight,
6353 descriptor"><strong>4.4</strong></a>
6355 <li>property, <a href="#propdef-font-weight" title="font-weight,
6356 property"><strong>3.2</strong></a>
6357 </ul>
6359 <li>font_face_rule, <a href="#fontfacerule"
6360 title="font_face_rule"><strong>4.1</strong></a>
6362 <li>FONT_FACE_SYM, <a href="#fontfacesym"
6363 title="FONT_FACE_SYM"><strong>4.1</strong></a>
6365 <li>font_family_name, <a href="#fontfamilyname"
6366 title="font_family_name"><strong>6.9</strong></a>
6368 <li>font_family_name_list, <a href="#fontfamilynamelist"
6369 title="font_family_name_list"><strong>6.9</strong></a>
6371 <li>font_feature_values_rule, <a href="#fontfeaturevaluesrule"
6372 title="font_feature_values_rule"><strong>6.9</strong></a>
6374 <li>FONT_FEATURE_VALUES_SYM, <a href="#fontfeaturevaluessym"
6375 title="FONT_FEATURE_VALUES_SYM"><strong>6.9</strong></a>
6377 <li>full-width, <a href="#full-width"
6378 title=full-width><strong>6.10</strong></a>
6380 <li>historical-forms, <a href="#historical-forms"
6381 title=historical-forms><strong>6.8</strong></a>
6383 <li>historical-ligatures, <a href="#historical-ligatures"
6384 title=historical-ligatures><strong>6.4</strong></a>
6386 <li>italic, <a href="#italic" title=italic><strong>3.4</strong></a>
6388 <li>jis04, <a href="#jis04" title=jis04><strong>6.10</strong></a>
6390 <li>jis78, <a href="#jis78" title=jis78><strong>6.10</strong></a>
6392 <li>jis83, <a href="#jis83" title=jis83><strong>6.10</strong></a>
6394 <li>jis90, <a href="#jis90" title=jis90><strong>6.10</strong></a>
6396 <li>lighter, <a href="#lighter" title=lighter><strong>3.2</strong></a>
6398 <li>lining-nums, <a href="#lining-nums"
6399 title=lining-nums><strong>6.7</strong></a>
6401 <li>monospace, definition of, <a href="#monospace0" title="monospace,
6402 definition of"><strong>#</strong></a>
6404 <li>no-common-ligatures, <a href="#no-common-ligatures"
6405 title=no-common-ligatures><strong>6.4</strong></a>
6407 <li>no-contextual, <a href="#no-contextual"
6408 title=no-contextual><strong>6.4</strong></a>
6410 <li>no-discretionary-ligatures, <a href="#no-discretionary-ligatures"
6411 title=no-discretionary-ligatures><strong>6.4</strong></a>
6413 <li>no-historical-ligatures, <a href="#no-historical-ligatures"
6414 title=no-historical-ligatures><strong>6.4</strong></a>
6416 <li>none
6417 <ul>
6418 <li>font-kerning, <a href="#font-kerning-none-value" title="none,
6419 font-kerning"><strong>6.3</strong></a>
6421 <li>font-size-adjust, <a href="#font-size-adjust-none-value"
6422 title="none, font-size-adjust"><strong>3.6</strong></a>
6424 <li>font-variant, <a href="#font-variant-none-value" title="none,
6425 font-variant"><strong>6.11</strong></a>
6427 <li>font-variant-ligatures, <a href="#font-variant-ligatures-none-value"
6428 title="none, font-variant-ligatures"><strong>6.4</strong></a>
6429 </ul>
6431 <li>normal
6432 <ul>
6433 <li>font-feature-settings, <a href="#font-feature-settings-normal-value"
6434 title="normal, font-feature-settings"><strong>6.12</strong></a>
6436 <li>font-kerning, <a href="#font-kerning-normal-value" title="normal,
6437 font-kerning"><strong>6.3</strong></a>
6439 <li>font-language-override, <a
6440 href="#font-language-override-normal-value" title="normal,
6441 font-language-override"><strong>6.13</strong></a>
6443 <li>font-stretch, <a href="#font-stretch-normal-value" title="normal,
6444 font-stretch"><strong>3.3</strong></a>
6446 <li>font-style, <a href="#font-style-normal-value" title="normal,
6447 font-style"><strong>3.4</strong></a>
6449 <li>font-variant, <a href="#font-variant-normal-value" title="normal,
6450 font-variant"><strong>6.11</strong></a>
6452 <li>font-variant-alternates, <a
6453 href="#font-variant-alternates-normal-value" title="normal,
6454 font-variant-alternates"><strong>6.8</strong></a>
6456 <li>font-variant-caps, <a href="#font-variant-caps-normal-value"
6457 title="normal, font-variant-caps"><strong>6.6</strong></a>
6459 <li>font-variant-east-asian, <a
6460 href="#font-variant-east-asian-normal-value" title="normal,
6461 font-variant-east-asian"><strong>6.10</strong></a>
6463 <li>font-variant-ligatures, <a
6464 href="#font-variant-ligatures-normal-value" title="normal,
6465 font-variant-ligatures"><strong>6.4</strong></a>
6467 <li>font-variant-numeric, <a href="#font-variant-numeric-normal-value"
6468 title="normal, font-variant-numeric"><strong>6.7</strong></a>
6470 <li>font-weight, <a href="#font-weight-normal-value" title="normal,
6471 font-weight"><strong>3.2</strong></a>
6472 </ul>
6474 <li>oblique, <a href="#oblique" title=oblique><strong>3.4</strong></a>
6476 <li>oldstyle-nums, <a href="#oldstyle-nums"
6477 title=oldstyle-nums><strong>6.7</strong></a>
6479 <li>ordinal, <a href="#ordinal" title=ordinal><strong>6.7</strong></a>
6481 <li>ornaments, <a href="#ornaments"
6482 title=ornaments><strong>6.8</strong></a>
6484 <li>petite-caps, <a href="#petite-caps"
6485 title=petite-caps><strong>6.6</strong></a>
6487 <li>proportional-nums, <a href="#proportional-nums"
6488 title=proportional-nums><strong>6.7</strong></a>
6490 <li>proportional-width, <a href="#proportional-width"
6491 title=proportional-width><strong>6.10</strong></a>
6493 <li>renderer, <a href="#renderer" title=renderer><strong>#</strong></a>
6495 <li>ruby, <a href="#ruby" title=ruby><strong>6.10</strong></a>
6497 <li>sans-serif, definition of, <a href="#sans-serif0" title="sans-serif,
6498 definition of"><strong>#</strong></a>
6500 <li>semi-condensed, <a href="#semi-condensed-"
6501 title=semi-condensed><strong>3.3</strong></a>
6503 <li>semi-expanded, <a href="#semi-expanded"
6504 title=semi-expanded><strong>3.3</strong></a>
6506 <li>serif, definition of, <a href="#serif0" title="serif, definition
6507 of"><strong>#</strong></a>
6509 <li>simplified, <a href="#simplified"
6510 title=simplified><strong>6.10</strong></a>
6512 <li>slashed-zero, <a href="#slashed-zero"
6513 title=slashed-zero><strong>6.7</strong></a>
6515 <li>small-caps, <a href="#small-caps"
6516 title=small-caps><strong>6.6</strong></a>
6518 <li>src, <a href="#descdef-src" title=src><strong>4.3</strong></a>
6520 <li>stacked-fractions, <a href="#stacked-fractions"
6521 title=stacked-fractions><strong>6.7</strong></a>
6523 <li>style sheet
6524 <ul>
6525 <li>as conformance class, <a href="#style-sheet" title="style sheet, as
6526 conformance class"><strong>#</strong></a>
6527 </ul>
6529 <li>styleset, <a href="#styleset" title=styleset><strong>6.8</strong></a>
6531 <li>stylistic, <a href="#stylistic"
6532 title=stylistic><strong>6.8</strong></a>
6534 <li>swash, <a href="#swash" title=swash><strong>6.8</strong></a>
6536 <li>tabular-nums, <a href="#tabular-nums"
6537 title=tabular-nums><strong>6.7</strong></a>
6539 <li>titling-caps, <a href="#titling-caps"
6540 title=titling-caps><strong>6.6</strong></a>
6542 <li>traditional, <a href="#traditional"
6543 title=traditional><strong>6.10</strong></a>
6545 <li>ultra-condensed, <a href="#ultra-condensed"
6546 title=ultra-condensed><strong>3.3</strong></a>
6548 <li>ultra-expanded, <a href="#ultra-expanded"
6549 title=ultra-expanded><strong>3.3</strong></a>
6551 <li>unicase, <a href="#unicase" title=unicase><strong>6.6</strong></a>
6553 <li>unicode-range, <a href="#descdef-unicode-range"
6554 title=unicode-range><strong>4.5</strong></a>
6556 <li>weight, <a href="#weight" title=weight><strong>2</strong></a>
6558 <li>width, <a href="#width" title=width><strong>2</strong></a>
6559 </ul>
6560 <!--end-index-->
6562 <h2 class=no-num id=property-index>Property index</h2>
6563 <!--begin-properties-->
6565 <table class=proptable>
6566 <thead>
6567 <tr>
6568 <th>Property
6570 <th>Values
6572 <th>Initial
6574 <th>Applies to
6576 <th>Inh.
6578 <th>Percentages
6580 <th>Media
6582 <tbody>
6583 <tr>
6584 <th><a class=property href="#propdef-font">font</a>
6586 <td>[ [ <‘font-style’> || <font-variant-css21> ||
6587 <‘font-weight’> || <‘font-stretch’ ]?
6588 <‘font-size’> [ / <‘line-height’> ]?
6589 <‘font-family’> ] | caption | icon | menu | message-box |
6590 small-caption | status-bar
6592 <td>see individual properties
6594 <td>all elements
6596 <td>yes
6598 <td>see individual properties
6600 <td>visual
6602 <tr>
6603 <th><span class=property>font-family</span>
6605 <td>[ <family-name> | <generic-family> ] #
6607 <td>depends on user agent
6609 <td>all elements
6611 <td>yes
6613 <td>N/A
6615 <td>visual
6617 <tr>
6618 <th><a class=property
6619 href="#propdef-font-feature-settings">font-feature-settings</a>
6621 <td>normal | <feature-tag-value> #
6623 <td>normal
6625 <td>all elements
6627 <td>yes
6629 <td>N/A
6631 <td>visual
6633 <tr>
6634 <th><a class=property href="#propdef-font-kerning">font-kerning</a>
6636 <td>auto | normal | none
6638 <td>auto
6640 <td>all elements
6642 <td>yes
6644 <td>N/A
6646 <td>visual
6648 <tr>
6649 <th><a class=property
6650 href="#propdef-font-language-override">font-language-override</a>
6652 <td>normal | <string>
6654 <td>normal
6656 <td>all elements
6658 <td>yes
6660 <td>N/A
6662 <td>visual
6664 <tr>
6665 <th><a class=property href="#propdef-font-size">font-size</a>
6667 <td><absolute-size> | <relative-size> | <length> |
6668 <percentage>
6670 <td>medium
6672 <td>all elements
6674 <td>yes
6676 <td>refer to parent element's font size
6678 <td>visual
6680 <tr>
6681 <th><a class=property
6682 href="#propdef-font-size-adjust">font-size-adjust</a>
6684 <td>none | auto | <number>
6686 <td>none
6688 <td>all elements
6690 <td>yes
6692 <td>N/A
6694 <td>visual
6696 <tr>
6697 <th><span class=property>font-stretch</span>
6699 <td>normal | ultra-condensed | extra-condensed | condensed |
6700 semi-condensed | semi-expanded | expanded | extra-expanded |
6701 ultra-expanded
6703 <td>normal
6705 <td>all elements
6707 <td>yes
6709 <td>N/A
6711 <td>visual
6713 <tr>
6714 <th><span class=property>font-style</span>
6716 <td>normal | italic | oblique
6718 <td>normal
6720 <td>all elements
6722 <td>yes
6724 <td>N/A
6726 <td>visual
6728 <tr>
6729 <th><a class=property href="#propdef-font-synthesis">font-synthesis</a>
6731 <td>none | [ weight || style ]
6733 <td>weight style
6735 <td>all elements
6737 <td>yes
6739 <td>N/A
6741 <td>visual
6743 <tr>
6744 <th><span class=property>font-variant</span>
6746 <td>normal | none | [ <common-lig-values> ||
6747 <discretionary-lig-values> || <historical-lig-values> ||
6748 <contextual-alt-values> || stylistic(<feature-value-name>)
6749 || historical-forms || styleset(<feature-value-name> #) ||
6750 character-variant(<feature-value-name> #) ||
6751 swash(<feature-value-name>) ||
6752 ornaments(<feature-value-name>) ||
6753 annotation(<feature-value-name>) || [ small-caps | all-small-caps
6754 | petite-caps | all-petite-caps | unicase | titling-caps ] ||
6755 <numeric-figure-values> || <numeric-spacing-values> ||
6756 <numeric-fraction-values> || ordinal || slashed-zero ||
6757 <east-asian-variant-values> || <east-asian-width-values> ||
6758 ruby ]
6760 <td>normal
6762 <td>all elements
6764 <td>yes
6766 <td>see individual properties
6768 <td>visual
6770 <tr>
6771 <th><a class=property
6772 href="#propdef-font-variant-alternates">font-variant-alternates</a>
6774 <td>normal | [ stylistic(<feature-value-name>) || historical-forms
6775 || styleset(<feature-value-name> #) ||
6776 character-variant(<feature-value-name> #) ||
6777 swash(<feature-value-name>) ||
6778 ornaments(<feature-value-name>) ||
6779 annotation(<feature-value-name>) ]
6781 <td>normal
6783 <td>all elements
6785 <td>yes
6787 <td>N/A
6789 <td>visual
6791 <tr>
6792 <th><a class=property
6793 href="#propdef-font-variant-caps">font-variant-caps</a>
6795 <td>normal | small-caps | all-small-caps | petite-caps | all-petite-caps
6796 | unicase | titling-caps
6798 <td>normal
6800 <td>all elements
6802 <td>yes
6804 <td>N/A
6806 <td>visual
6808 <tr>
6809 <th><a class=property
6810 href="#propdef-font-variant-east-asian">font-variant-east-asian</a>
6812 <td>normal | [ <east-asian-variant-values> ||
6813 <east-asian-width-values> || ruby ]
6815 <td>normal
6817 <td>all elements
6819 <td>yes
6821 <td>N/A
6823 <td>visual
6825 <tr>
6826 <th><a class=property
6827 href="#propdef-font-variant-ligatures">font-variant-ligatures</a>
6829 <td>normal | none | [ <common-lig-values> ||
6830 <discretionary-lig-values> || <historical-lig-values> ||
6831 <contextual-alt-values> ]
6833 <td>normal
6835 <td>all elements
6837 <td>yes
6839 <td>N/A
6841 <td>visual
6843 <tr>
6844 <th><a class=property
6845 href="#propdef-font-variant-numeric">font-variant-numeric</a>
6847 <td>normal | [ <numeric-figure-values> ||
6848 <numeric-spacing-values> || <numeric-fraction-values> ||
6849 ordinal || slashed-zero ]
6851 <td>normal
6853 <td>all elements
6855 <td>yes
6857 <td>N/A
6859 <td>visual
6861 <tr>
6862 <th><a class=property
6863 href="#propdef-font-variant-position">font-variant-position</a>
6865 <td>normal | sub | super
6867 <td>normal
6869 <td>all elements
6871 <td>yes
6873 <td>N/A
6875 <td>visual
6877 <tr>
6878 <th><span class=property>font-weight</span>
6880 <td>normal | bold | bolder | lighter | 100 | 200 | 300 | 400 | 500 | 600
6881 | 700 | 800 | 900
6883 <td>normal
6885 <td>all elements
6887 <td>yes
6889 <td>N/A
6891 <td>visual
6892 </table>
6893 <!--end-properties-->
6894 <!--begin-descriptors-->
6896 <table class=proptable>
6897 <thead>
6898 <tr>
6899 <th>Descriptor
6901 <th>Value
6903 <th>Initial
6905 <th>Percentages
6907 <th>Media
6909 <tbody>
6910 <tr>
6911 <th><span class=property>font-family</span>
6913 <td><family-name>
6915 <td>N/A
6917 <tr>
6918 <th><a class=property
6919 href="#propdef-font-feature-settings">font-feature-settings</a>
6921 <td>normal | <feature-tag-value> #
6923 <td>normal
6925 <tr>
6926 <th><span class=property>font-stretch</span>
6928 <td>normal | ultra-condensed | extra-condensed | condensed |
6929 semi-condensed | semi-expanded | expanded | extra-expanded |
6930 ultra-expanded
6932 <td>normal
6934 <tr>
6935 <th><span class=property>font-style</span>
6937 <td>normal | italic | oblique
6939 <td>normal
6941 <tr>
6942 <th><span class=property>font-variant</span>
6944 <td>normal | none | [ <common-lig-values> ||
6945 <discretionary-lig-values> || <historical-lig-values> ||
6946 <contextual-alt-values> || stylistic(<feature-value-name>)
6947 || historical-forms || styleset(<feature-value-name> #) ||
6948 character-variant(<feature-value-name> #) ||
6949 swash(<feature-value-name>) ||
6950 ornaments(<feature-value-name>) ||
6951 annotation(<feature-value-name>) || [ small-caps | all-small-caps
6952 | petite-caps | all-petite-caps | unicase | titling-caps ] ||
6953 <numeric-figure-values> || <numeric-spacing-values> ||
6954 <numeric-fraction-values> || ordinal || slashed-zero ||
6955 <east-asian-variant-values> || <east-asian-width-values> ||
6956 ruby ]
6958 <td>normal
6960 <tr>
6961 <th><span class=property>font-weight</span>
6963 <td>normal | bold | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900
6965 <td>normal
6967 <tr>
6968 <th><a class=property href="#descdef-src">src</a>
6970 <td>[ <url> [format(<string> #)]? | <font-face-name> ] #
6972 <td>N/A
6974 <tr>
6975 <th><a class=property href="#descdef-unicode-range">unicode-range</a>
6977 <td><urange> #
6979 <td>U+0-10FFFF
6980 </table>
6981 <!--end-descriptors-->
6982 <script type="text/javascript">
6983 window.onload = function () {
6984 if (!("devicePixelRatio" in window && window.devicePixelRatio > 1)) return;
6985 var i, hiresElements = document.getElementsByClassName("hires");
6986 for (i = 0; i < hiresElements.length; i++) {
6987 var h = hiresElements[i];
6988 if (h.tagName != "IMG") continue;
6989 var src = h.getAttribute("src");
6990 var src2x = src.replace(/\.\w+$/, function(m) { return "@2x" + m; });
6991 h.src = src2x;
6992 }
6993 }
6994 </script>
6995 </html>
6996 <!-- Keep this comment at the end of the file
6997 Local variables:
6998 mode: sgml
6999 sgml-declaration:"~/SGML/HTML4.decl"
7000 sgml-default-doctype-name:"html"
7001 sgml-minimize-attributes:t
7002 sgml-nofill-elements:("pre" "style" "br")
7003 sgml-live-element-indicator:t
7004 sgml-omittag:nil
7005 sgml-shorttag:nil
7006 sgml-namecase-general:t
7007 sgml-general-insert-case:lower
7008 sgml-always-quote-attributes:t
7009 sgml-indent-step:nil
7010 sgml-indent-data:t
7011 sgml-parent-document:nil
7012 sgml-exposed-tags:nil
7013 sgml-local-catalogs:nil
7014 sgml-local-ecat-files:nil
7015 End:
7016 -->
7017 <!--
7019 to do:
7021 - wording of OpenType family name handling
7022 - handling combining sequences in the font matching algorithm
7023 - fix-up fi ligature example
7025 -->
