css-ruby/Overview.src.html@8a1d4d700090
css-ruby/Overview.src.html
Mon, 17 Jun 2013 21:35:27 +0900
- author
- fantasai <fantasai.cvs@inkedblade.net>
- date
- Mon, 17 Jun 2013 21:35:27 +0900
- changeset 8479
- 8a1d4d700090
- parent 8271
- css-ruby/Overview.html@431d7b028f22
- child 8490
- 32c9ef6fe05c
- permissions
- -rw-r--r--
[css-ruby] Switch to using preprocessor for CSS Ruby
1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
5 <title>CSS Ruby Module Level 1</title>
6 <link rel=contents href="#contents">
7 <link rel=index href="#index">
8 <link rel="stylesheet" type="text/css" href="../default.css">
9 <link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
10 <link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/W3C-[STATUS].css">
11 </head>
13 <body class="h-entry">
15 <div class="head">
16 <!--logo-->
18 <h1 class="p-name">CSS Ruby Module Level 1</h1>
20 <h2 class="no-num no-toc">[LONGSTATUS] <time class="dt-updated" datetime="[CDATE]">[DATE]</time> <!-- for HTML4 doctype: <span class="value-title" title="[CDATE]">[DATE]</span></span> --> </h2>
21 <dl>
22 <dt>This version:
23 <dd><a class="u-url" href="[VERSION]">[VERSION]</a>
25 <dt>Latest version:
26 <dd><a href="http://www.w3.org/TR/[SHORTNAME]/">http://www.w3.org/TR/css3-ruby/</a>
28 <dt>Editor's draft:
29 <dd><a href="http://dev.w3.org/csswg/[SHORTNAME]/">http://dev.w3.org/csswg/[SHORTNAME]/</a>
30 (<a href="https://dvcs.w3.org/hg/csswg/log/tip/[SHORTNAME]/Overview.src.html">change log</a>)
32 <dt>Previous version:
33 <dd><a href="http://www.w3.org/TR/2011/WD-css3-ruby-20110630/">
34 http://www.w3.org/TR/2011/WD-css3-ruby-20110630/</a>
36 <dt>Issue Tracking:</dt>
37 <dd><a rel="issues" href="http://www.w3.org/Style/CSS/Tracker/products/FIXME">http://www.w3.org/Style/CSS/Tracker/products/FIXME</a>
39 <dt>Feedback:</dt>
40 <dd><a href="mailto:www-style@w3.org?subject=%5BSHORTNAME%5D%20feedback"
41 >www-style@w3.org</a>
42 with subject line “<kbd>[[SHORTNAME]]
43 <var>… message topic …</var></kbd>”
44 (<a rel="discussion" href="http://lists.w3.org/Archives/Public/www-style/"
45 >archives</a>)
47 <dt>Editors:
48 <dd class="p-author h-card vcard">
49 <a class="p-name fn u-url url" rel="author"
50 href="http://fantasai.inkedblade.net/contact">Elika J. Etemad</a>,
51 <a class="p-org org h-org" href="http://www.mozilla.org/">Mozilla</a>
52 <dd class="p-author h-card vcard">
53 <a class="p-name fn u-url url" rel="author"
54 href="mailto:koji.a.ishii@mail.rakuten.com">Koji Ishii</a>,
55 <span class="p-org org">Rakuten, Inc.</span>
56 <dd class="p-author h-card vcard">
57 <a class="p-name fn u-url url" rel="author"
58 href="mailto:ishida@w3.org">Richard Ishida</a>,
59 <span class="p-org org">W3C</span>
61 <dt>Former editors:
62 <dd>Michel Suignard, Microsoft
63 <dd>Marcin Sawicki, Microsoft
64 </dl>
66 <!--copyright-->
68 <hr title="Separator for header">
69 </div>
71 <h2 class="no-num no-toc" id="abstract">Abstract</h2>
73 <p>
74 <span class="p-summary">
75 “Ruby” are short runs of text alongside the base text,
76 typically used in East Asian documents to indicate pronunciation
77 or to provide a short annotation.
78 This module describes the rendering model and formatting controls
79 related to displaying ruby annotations in CSS.
80 </span>
82 <a href="http://www.w3.org/TR/CSS/">CSS</a> is a language for describing
83 the rendering of structured documents (such as HTML and XML) on screen, on
84 paper, in speech, etc.
86 <h2 class="no-num no-toc" id="status">Status of this document</h2>
88 <!--status-->
90 <p>The following features are at risk: …
92 <h2 class="no-num no-toc" id="contents">
93 Table of Contents</h2>
95 <!--toc-->
97 <h2 id="intro">
98 Introduction</h2>
100 <p><em>This section is not normative.</em>
102 <h3 id="placement">
103 Module interactions</h3>
105 <p>This module extends the inline box model of CSS Level 2 [[!CSS21]]
106 to support ruby.
108 <p>None of the properties in this module apply to the <code>::first-line</code> or
109 <code>::first-letter</code> pseudo-elements.
111 <h3 id="values">
112 Values</h3>
114 <p>This specification follows the
115 <a href="http://www.w3.org/TR/CSS21/about.html#property-defs">CSS property
116 definition conventions</a> from [[!CSS21]]. Value types not defined in
117 this specification are defined in CSS Level 2 Revision 1 [[!CSS21]].
118 Other CSS modules may expand the definitions of these value types: for
119 example [[CSS3VAL]], when combined with this module, expands the
120 definition of the <var><length></var> value type as used in this specification.</p>
122 <p>In addition to the property-specific values listed in their definitions,
123 all properties defined in this specification also accept the
124 <a href="http://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>
125 keyword as their property value. For readability it has not been repeated
126 explicitly.
128 <h3 id="conventions">
129 Document conventions</h3>
131 <p>There are a number of illustrations in this document for which the following
132 legend is used:</p>
134 <p><img alt="Symbolic wide-cell glyph representation" class="example"
135 width="39" height="39" src="images/fullwidth.gif" /> - wide-cell glyph (e.g. Han)
136 which is the <i>n</i>-th character in the text run, they may also appear as
137 half size boxes when used as annotations.<br />
138 <img alt="Symbolic narrow-cell glyph representation" class="example"
139 width="19" height="39" src="images/halfwidth.gif" /> - narrow-cell glyph (e.g. Roman)
140 which is the <i>n</i>-th glyph in the text run.<br />
141 </p>
143 <p>Many typographical properties in East Asian typography depend on the fact
144 that a character is typically rendered as either a wide or narrow character. All
145 characters described by the Unicode Standard [[UNICODE]] can be categorized by a
146 width property. This is covered by the Unicode Standard Annex
147 [[UAX11]]</a>. </p>
149 <p>The orientation which the above symbols assume in the diagrams corresponds
150 to the orientation that the glyphs they represent are intended to assume when
151 rendered by the user agent. Spacing between these characters in the diagrams is
152 usually symbolic, unless intentionally changed to make a point.</p>
154 <h3 id="ruby-def">
155 What is ruby?</h3>
157 <p>"Ruby" is the commonly used name for a run of text that appears in the
158 immediate vicinity of another run of text, referred to as the "base", and
159 serves as an annotation or a pronunciation guide associated with that run of
160 text. Ruby, as used in Japanese, is described in JIS X-4051 [[JIS4051]] (in Japanese) and in Requirements for Japanese Text Layout [[JLREQ]] (in English and Japanese)]. The ruby structure and the XHTML markup to represent it
161 is described in the Ruby Annotation [[RUBY]] specification. This
162 section describes the CSS properties relevant to ruby. The following figures
163 show two examples of Ruby.</p>
165 <div class="figure">
166 <p>
167 <img alt="Example of ruby applied on top of a Japanese expression"
168 class="example" src="images/licence.png" /></p>
170 <p><b>Figure 2.2.1</b>: Example of ruby used in Japanese (simple case)</p>
171 </div>
173 <div class="figure">
174 <p>
175 <img
176 alt="Example showing complex ruby with annotation text before and after
177 the base characters"
178 class="example" src="images/ruby-univ.gif" width="277" height="108" /></p>
180 <p><strong>Figure 2.2.2</strong>: Complex ruby with annotation text before and after
181 the base characters</p>
182 </div>
184 <p>In the first example, a single annotation is used to annotate the base
185 sequence. In Japanese typography, this simple case is sometimes called "<span lang="ja">taigo</span> ruby" or group-ruby (per-word ruby).</p>
187 <p>In the second example, multiple annotations are attached to a base
188 sequence, the hiragana characters on top refer to the pronunciation of each of the
189 base Kanji characters (annotated in a <a href="#g-monoruby">mono-ruby</a> fashion), while the words 'Keio'
190 and 'University' on the bottom are
191 annotations describing the English translation of respectively the first four
192 and the last two Kanji characters
193 of the base. To allow correct association between the hiragana characters and
194 their corresponding Kanji base characters, the spacing between these Kanji
195 characters may be adjusted (this happens around the fourth Kanji character in the
196 figure 2.2.2 above).</p>
198 <p class="Note"><span class="note-label">Note:</span> To avoid variable spacing between the Kanji
199 characters in the example above the hiragana annotations can also be created as
200 a simple annotation ruby.</p>
202 <p>The two examples correspond respectively to two types of ruby: simple ruby using simple ruby markup and complex ruby using complex ruby
203 markup.</p>
205 <h2 id="ruby-model">
206 Ruby Formatting Model</h2>
208 <h3 id="display">
209 Ruby specific 'display' property values</h3>
211 <p>The CSS ruby model is based on the W3C Ruby Annotation Recommendation [[RUBY]].
212 The Recommendation specifies the ruby structure in a way to closely parallel
213 the visual layout of the ruby element. In this model, a ruby consists of one
214 or more base elements associated with one or more annotation elements.</p>
216 <p>The CSS model does not require that the document language include elements
217 that correspond to each of these components. For document languages (such as
218 XML applications) that do not have pre-defined ruby elements, authors must map
219 document language elements to ruby elements; this is done with the 'display'
220 property. The following 'display' values assign ruby semantics to an arbitrary
221 element:</p>
222 <dl>
223 <dt><strong>ruby</strong> (in XHTML: ruby)</dt>
224 <dd>Specifies that an element defines a ruby structure.</dd>
225 <dt><strong>ruby-base</strong> (in XHTML: rb)</dt>
226 <dd>Specifies that an element defines a ruby base.</dd>
227 <dt><strong>ruby-text</strong> (in XHTML: rt)</dt>
228 <dd>Specifies that an element defines a ruby text.</dd>
229 <dt><strong>ruby-base-container</strong> (in XHTML: rbc)</dt>
230 <dd>Specifies that an element contains one or more ruby base.</dd>
231 <dt><strong>ruby-text-container</strong> (in XHTML: rtc)</dt>
232 <dd>Specifies that an element contains one or more ruby text.</dd>
233 </dl>
235 <p class="issue"><span class="issuehead">Issue: </span> I18n WG proposes that there should be a display value rp also, to allow XML-based formats to associate rp behaviour with elements. See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20display:+rp+value&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">thread</a>.</p>
237 <p>The <a
238 href="http://www.w3.org/TR/ruby/#ruby"><samp>rbspan</samp></a> attribute should
239 also be used by XML applications to allow annotation spanning; but in addition, the
240 '<a href="#ruby-span">ruby-span</a>' property must be used by those applications to indicate to the user agent the number of
241 ruby base elements to be spanned.</p>
243 <h3 id="box-model">
244 Ruby box model</h3>
246 <p class="issue"><span class="issuehead">Issue: </span> The spec needs to address anonymous box generation rules (and to make them compatible with HTML5 ruby markup).</p>
247 <p>In the following description, the elements specified by Ruby
248 Annotation [[RUBY]] are used to describe the box model. As mentioned
249 earlier, a user agent can obtain the same results by using the Ruby specific 'display'
250 property values. </p>
252 <p>For a user agent that supports the ruby markup, the ruby structure consists of three or more
253 boxes. The outermost container is the <a
254 href="http://www.w3.org/TR/ruby/#ruby"><samp>ruby</samp></a> element itself.
255 In the simple case, it is a container for two non-overlapping boxes: the ruby
256 text box (<a href="http://www.w3.org/TR/ruby/#rt"><samp>rt</samp></a> element)
257 and the ruby base box (<a
258 href="http://www.w3.org/TR/ruby/#rb"><samp>rb</samp></a> element). The
259 positioning of these two boxes relative to each other is controlled by the <a
260 href="#rubypos">'ruby-position'</a> property.</p>
262 <div class="figure">
263 <img class="example" width="223" height="93"
264 alt="Diagram of the ruby box model consisting of two boxes, one on top of the other, enclosed within a third box representing the ruby element"
265 src="images/r-box-t.gif" />
267 <p><b>Figure 3.2.1</b>: Ruby box model (simple case)</p>
268 </div>
270 <p>In the case of complex ruby, the ruby element is a container for two or
271 three non-overlapping boxes: one ruby base collection (<a
272 href="http://www.w3.org/TR/ruby/#rbc"><samp>rbc</samp></a> element), and one
273 or two ruby text collections (<a
274 href="http://www.w3.org/TR/ruby/#rtc"><samp>rtc</samp></a> element). The
275 <samp>rbc</samp> element is itself a container for one or several ruby base
276 box (<samp>rb</samp> element), while each <samp>rtc</samp> element is a
277 container for one or several ruby text box (rt element). The position of the
278 <samp>rtc</samp> element in relation to the related <samp>rbc</samp> element
279 is controlled by the <a href="#rubypos">'ruby-position'</a> property. The two
280 following figures show examples of these complex ruby.</p>
282 <div class="figure">
283 <img src="images/r-box-g.gif"
284 alt="Diagram of a group ruby with a full ruby text above and partial ruby text below" width="408" height="170" />
286 <p><b>Figure 3.2.2</b>: Ruby box model (complex ruby with an empty rt element
287 after)</p>
288 </div>
290 <p>In the example above, the ruby text after (below) the ruby bases contains two <samp>rt</samp> elements with the first one
291 being empty, the empty <samp>rt</samp> element corresponds to the first part
292 of the ruby base collection (the first part is identified by the first <samp>rb</samp> element
293 within the <samp> rbc</samp> element).</p>
295 <div class="figure">
296 <img src="images/r-box-h.gif"
297 alt="Diagram of a group ruby with a spanning ruby text above and partial ruby text below" width="400" height="173" />
299 <p><b>Figure 3.2.3</b>: Ruby box model (complex ruby with a spanning ruby text
300 element)</p>
301 </div>
303 <p>In the example above, the ruby text before (above) the ruby bases spans the whole ruby base collection. The
304 ruby text after (below) the ruby bases still contain two <samp>rt</samp> elements, one of
305 which is empty. The spanning behavior of <samp>rt</samp> text elements is
306 controlled by the <a
307 href="http://www.w3.org/TR/ruby/#ruby"><samp>rbspan</samp></a> attribute in a
308 way similar to the <samp>colspan</samp> attribute used for table column.</p>
310 <p class="issue"><span class="issuehead">Issue: </span> The examples above contain the term 'group ruby', which is not used elsewhere in this specification. It appears to be used in a way that is different to the use of the term in JLREQ. I propose to replace it with just 'ruby'.</p>
311 <p class="note"><span class="note-label">Note:</span> The visual description of the ruby elements does not refer
312 necessarily to the logical orders of the elements</p>
314 <p>The width of the ruby box is by default determined by its widest child
315 element, whose width in turn is determined by its content. The width of all direct
316 children of the <samp>ruby</samp> element is the width of the widest children. In this respect, the ruby
317 box is much like a two or three row <samp>table</samp> element, with the
318 following exceptions:</p>
319 <ul>
320 <li>the ruby box is an inline element, like an image, even though it itself,
321 like a table, is a container of other boxes</li>
322 <li>the equivalent of the cells: the <samp>rb</samp> element and the
323 <samp>rt</samp> text element can only contain inline-level elements.</li>
324 <li>the content of each 'cell' is always measured at its maximum width</li>
325 <li>unlike a table, a ruby element doesn't have to fit in a line, the ruby
326 box may be split into several boxes at line boundary, depending of the
327 spanning of the ruby texts. This is however only possible for the complex
328 ruby and can only happen at the boundary of non spanning elements.</li>
329 <li>both the ruby text and the ruby base boxes may overlap with adjacent
330 text (outside of the ruby element) if an appropriate <a
331 href="#rubyover">'ruby-overhang'</a> parameter is set via CSS. Note
332 however that the actual content of the ruby base cannot overlap with that
333 adjacent text. The distribution of the content of the ruby base within the
334 ruby base box is controlled by the <a href="#rubyalign">'ruby-align'</a>
335 property.</li>
336 </ul>
338 <p>If the ruby text is not allowed to overhang, then the ruby behaves like a
339 traditional box, i.e. only its contents are rendered within its boundaries and
340 adjacent elements do not cross the box boundary:</p>
342 <div class="figure">
343 <p><img class="example" width="220" height="91"
344 alt="Diagram showing the ruby boxes interacting with adjacent text"
345 src="images/ro-n.gif" /></p>
347 <p><b>Figure 3.2.4</b>: Simple ruby whose text is not allowed to overhang
348 adjacent text</p>
349 </div>
351 <p>However, if ruby text is allowed to overhang adjacent elements and it
352 happens to be wider than its base, then the adjacent content is partially
353 rendered within the area of the ruby base box, while the ruby text may be
354 partially overlapping with the upper blank parts of the adjacent content:</p>
356 <div class="figure">
357 <p><img class="example" width="177" height="91"
358 alt="Diagram showing the ruby boxes interacting with adjacent text"
359 src="images/ro-a.gif" /></p>
361 <p><b>Figure 3.2.5</b>: Simple ruby whose text is allowed to overhang adjacent
362 text</p>
363 </div>
365 <p>The ruby text related to a ruby base can never overhang another ruby
366 base.</p>
368 <p>The alignment of the contents of the base or the ruby text is not affected
369 by the overhanging behavior. The alignment is achieved the same way regardless
370 of the overhang behavior setting and it is computed before the space available
371 for overlap is determined. It is controlled by the <a
372 href="#rubyalign">'ruby-align'</a> property.</p>
374 <p>The exact circumstances in which the ruby text will overhang other
375 elements, and to what degree it will do so, will be controlled by the <a
376 href="#rubyover">'ruby-overhang'</a> property.</p>
378 <p>This entire logic applies the same way in vertical ideographic layout, only
379 the dimension in which it works in such a layout is vertical, instead of
380 horizontal.</p>
382 <p class="note"><span class="note-label">Note:</span> Because the purpose of the XHTML <samp>rp</samp> element
383 [[RUBY]] is to allow pre-existing user agents
384 to parenthesize ruby text content, an XHTML user agent should use a styling rule
385 for these elements that avoids rendering them such as <samp>rp {display:
386 none}</samp>.</p>
388 <h3 id="ruby-line-height">
389 Ruby box and line stacking</h3>
391 <p>The interaction of the ruby box and line stacking is controlled by the
392 'line-stacking-ruby' property described in the CSS3 Line Module. That property
393 takes two values: 'include-ruby' and 'exclude-ruby. Depending on the property
394 value, the ruby box is considered or excluded for line stacking. Even if the
395 ruby box is considered for line stacking, some values of the
396 'line-stacking-strategy' property (also described in the CSS3 Line module) can
397 still create occurrences where a the ruby box will eventually be ignored (e.g.
398 case where the 'line-stacking-strategy' value is 'block-line-height').</p>
400 <p>In the following figure, each line box is shown with leading space
401 distributed before and after the two text segments ('Previous line' and 'Ruby
402 base'); the dotted lines show the line box for each line. The
403 'line-stacking-ruby' property is set to 'exclude-ruby'. The achieved effect is
404 that the ruby box does not affect the line to line spacing. It is however the
405 responsibility of the style author to avoid 'bleeding' effects between the ruby
406 text and the surrounding text of images.</p>
408 <div class="figure">
409 <p>
410 <img class="example"
411 alt="Diagram showing the ruby text using 2 half leading"
412 src="images/rlh-a.gif" width="210" height="138" /></p>
414 <p><b>Figure 3.3.1</b>: Excluded Ruby text</p>
415 </div>
418 <p>In the following figure, the line boxes have no extra leading space. The
419 'line-stacking-ruby' property is set to 'include-ruby' and the
420 'line-stacking-strategy' property is set to a value where inline boxes are
421 considered for line stacking. In this case, the line box with
422 the ruby text is affected and has its 'stack-height' increased by the amount
423 necessary to fit the ruby text.</p>
425 <div class="figure">
426 <p>
427 <img class="example"
428 alt="Diagram showing the ruby text expanding above base text"
429 src="images/rlh-b.gif" width="210" height="111" /></p>
431 <p><b>Figure 3.3.2</b>: Ruby text increasing line height</p>
432 </div>
433 <p>This mechanism allows rendering of evenly spaced lines of text within a
434 block-level element, whether a line contains ruby or not. The authors need
435 only to set for the block-level element a line height value larger than the
436 computed line-height of the largest ruby element within the block.</p>
438 <h3 id="ruby-line-breaking">
439 Ruby box and line breaking</h3>
441 <p>When a ruby falls at the end of a line where there is not sufficient room for the entire ruby to fit on the line, the complex ruby may be broken at locations where boxes of the ruby container align. Some examples are provided below to provide more clarity.</p>
443 <p>
444 <img class="example"
445 alt="Diagram showing the line breaking opportunity in a complex ruby"
446 src="images/r-break-a.gif" width="408" height="201" /></p>
448 <p><b>Figure 3.4.1</b>: Complex ruby line breaking opportunity</p>
450 <p>
451 <img class="example"
452 alt='Diagram showing the line breaking opportunity in a "Bopomofo" ruby'
453 src="images/r-break-b.gif" width="300" height="90" /></p>
455 <p><b>Figure 3.4.1</b>: "Bopomofo" ruby line breaking opportunity</p>
456 <p class="issue"><span class="issuehead">Issue: </span> Line breaks should only be allowed within ruby if the ruby base text can be broken at that point. E.g. if complex Ruby is used to annotate the two morphemes of "butterfly", the fact that we have added ruby annotations should not cause a line breaking opportunity to be present between "butter" and "fly" </p>
457 <h2 id="ruby-props">
458 Ruby Properties</h2>
460 <p>All properties, in addition to the noted values, take 'initial' and
461 'inherit'. These values are not repeated in each of the property value
462 enumeration. </p>
464 <h3 id="rubypos">
465 Ruby positioning: the 'ruby-position' property</h3>
467 <table class="propdef">
468 <tr>
469 <th>Name:
470 <td><dfn>ruby-position</dfn>
471 <tr>
472 <th>Value:
473 <td>before | after | inter-character | inline
474 <tr>
475 <th>Initial:
476 <td>before
477 <tr>
478 <th>Applies to:
479 <td>the parent of elements with display: ruby-text.
480 <tr>
481 <th>Inherited:
482 <td>yes
483 <tr>
484 <th>Percentages:
485 <td>N/A
486 <tr>
487 <th>Media:
488 <td>visual
489 <tr>
490 <th>Computed value:
491 <td>specified value (except for initial and inherit)
492 <tr>
493 <th>Animatable:
494 <td>no
495 <tr>
496 <th>Canonical order:
497 <td><abbr title="follows order of property value definition">per grammar</abbr>
498 </table>
499 <p class="issue"><span class="issuehead">Issue: </span> We replaced 'right' with 'inter-character', since that was its original intended purpose and such removes potential ambiguity with 'inline' or 'before'. Bopomofo ruby needs special handling by the implementation, if ruby is to always appear to the right. (Note that the user may also choose to position bopomofo ruby before the base, in which case they would use the normal 'before' setting.)</p>
500 <p>This property is used by the parent of elements with display: ruby-text to
501 control the position of the ruby text with respect to its base. Such parents
502 are typically either the <samp>ruby</samp> element itself (simple ruby) or the
503 <samp>rtc</samp> element (complex ruby). This assures that all parts of a <samp>rtc</samp>
504 element will be displayed in the same position. Possible values:</p>
505 <p class="issue"><span class="issuehead">Issue-107: </span> Roland Steiner has requested the addition of an auto value as default. See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=ruby-position%3A+undesirable+default+value+%27before%27+for+complex+ruby&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&period_month=&period_year=&index-grp=Public__FULL&index-type=t&type-index=www-style&resultsperpage=20&sortby=date">this thread</a> and <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=Styling+of+complex+Ruby&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&period_month=&period_year=&index-grp=Public__FULL&index-type=t&type-index=public-i18n-core&resultsperpage=20&sortby=date">this one</a>.</p>
506 <dl>
507 <dt><strong>before</strong></dt>
508 <dd>The ruby text appears before the base. This is the most common setting
509 used in ideographic East Asian writing systems. This is the initial
510 value.
512 <div class="figure">
513 <p>
514 <img
515 alt="Diagram of ruby glyph layout in horizontal mode with ruby text appearing above the base"
516 class="example" src="images/shinkansen-top.gif" width="140" height="33" /></p>
517 <p><b>Figure 4.1.1</b>: Top ruby in horizontal layout applied to
518 Japanese text</p>
519 </div>
520 <p>If the base appears in a vertical-ideographic layout mode, the ruby
521 appears on the right side of the base and is rendered in the same layout
522 mode as the base (i.e. vertical-ideographic).</p>
524 <div class="figure">
525 <p>
526 <img
527 alt="Diagram of ruby glyph layout in vertical mode with ruby text apearing vertically on the right of the base"
528 class="example" src="images/shinkansen-right.gif" width="33" height="141" /></p>
529 <p><b>Figure 4.1.2</b>: Top ruby in vertical ideographic layout applied
530 to Japanese text</p>
531 </div>
532 </dd>
533 <dt><strong>after</strong></dt>
534 <dd>The ruby text appears after the base. This is a relatively rare
535 setting used in ideographic East Asian writing systems, most easily
536 found in educational text.
538 <div class="figure">
539 <p>
540 <img
541 alt="Diagram of ruby glyph layout in horizontal mode with ruby text appearing below the base"
542 class="example" src="images/shinkansen-bottom.gif" width="142" height="36" /></p>
543 <p><b>Figure 4.1.3</b>: Bottom ruby in horizontal layout applied to
544 Japanese text</p>
545 </div>
546 <p>If the base appears in a vertical ideographic mode, the bottom ruby
547 appears on the left side of the base and is rendered in the same layout
548 mode as the base (i.e. vertical).</p>
550 <div class="figure">
551 <p>
552 <img
553 alt="Diagram of ruby glyph layout in vertical mode with ruby text apearing vertically on the left of the base"
554 class="example" src="images/shinkansen-left.gif" width="37" height="141" /></p>
555 <p><b>Figure 4.1.4</b>: Bottom ruby in vertical ideographic layout applied
556 to Japanese text</p>
557 </div>
558 </dd>
559 <dt><strong>inter-character</strong></dt>
560 <dd>
561 <p class="issue"><span class="issuehead">Issue: </span> We replaced 'right' with 'inter-character', since that was its original intended purpose and such removes potential ambiguity with 'inline' or 'before'. Bopomofo ruby needs special handling by the implementation, if ruby is to always appear to the right. (Note that the user may also choose to position bopomofo ruby before the base, in which case they would use the normal 'before' setting.) See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20Vertical+layout+not+enough+for+bopomofo&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">this thread</a> following a request from the i18n WG.</p>
562 <p>The ruby text appears on the right of the base. Unlike 'before' and
563 'after', this value is visual and is not relative to the text flow direction.</p>
565 <p>This value is provided for the special case of traditional Chinese as used especially in
566 Taiwan: ruby (made of <a href="#g-bopomofo"><span
567 lang="zh">bopomofo</span></a> glyphs) in that context appears vertically along
568 the right side of the base glyph, whether the layout of the base characters is vertical or horizontal:</p>
570 <div class="figure">
571 <p><img alt="Example of Taiwanese-style ruby" class="example"
572 width="138" height="42" src="images/bopomofo.gif" /></p>
573 <p><b>Figure 4.1.5</b>: "<span lang="zh">Bopomofo</span>" ruby in
574 traditional Chinese (ruby text shown in blue for clarity) in horizontal
575 layout</p>
576 </div>
577 <p class="note"><span class="note-label">Note:</span> The bopomofo
578 transcription is written in the normal way as part of the ruby text.
579 The user agent is responsible for ensuring the correct relative alignment
580 and positioning of the glyphs, including those corresponding to the
581 tone marks, when displaying. Tone marks are spacing characters that occur in memory at the end of the ruby text for each base character. They are usually displayed in a separate column to the right of the bopomofo characters, and the height of the tone mark depends on the number of characters in the syllable. One tone mark, however, is placed above the bopomofo, not to the right of it.</p>
582 <p class="note"><span class="note-label">Note:</span> To make bopomofo annotations appear before or after the base text, like annotations for most other East Asian writing systems, use the 'before' and 'after' values of ruby-position.</p>
583 <p>It is not defined how a user-agent should handle ruby text that is not bopomofo when the value of ruby-position is set to 'right'.</p>
584 <!-- See Taiwanese requirements doc for EPUB at http://epub-revision.googlecode.com/files/EGLS_TW_eng.ppt -->
585 </dd>
586 <dt><strong>inline</strong></dt>
587 <dd>
588 <p>Ruby text follows the ruby base with no special styling. The value can be used to disable ruby text positioning.</p>
589 <p>If the author has used the XHTML <samp>rp</samp> element [[RUBY]] they should set the <samp>display</samp> value for that element to <samp>inline</samp>, so that the ruby text is distinguishable from the base text. If no <samp>rp</samp> element has been used, the author can use the <samp>content</samp> property with the <samp>:before</samp> and <samp>:after</samp> pseudo-elements to set off the ruby text. </p>
590 <p class="issue"><span class="issuehead">Issue: </span> Here is a <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20inline+value+description+missing&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">request </a>for this section to be added, from the i18n WG..</p>
591 </dd>
592 </dl>
594 <p>If two rtc elements are set with the same ruby-position value, (for example
595 both 'before'), the relative position of the two elements is undefined. This
596 setting should not be used.</p>
598 <h3 id="rubyalign">
599 Ruby alignment: the 'ruby-align' property</h3>
601 <table class="propdef">
602 <tr>
603 <th>Name:
604 <td><dfn>ruby-align</dfn>
605 <tr>
606 <th>Value:
607 <td>auto | start | left | center | end | right | distribute-letter |
608 distribute-space | line-edge
609 <tr>
610 <th>Initial:
611 <td>auto
612 <tr>
613 <th>Applies to:
614 <td>all elements and generated content
615 <tr>
616 <th>Inherited:
617 <td>yes
618 <tr>
619 <th>Percentages:
620 <td>N/A
621 <tr>
622 <th>Media:
623 <td>visual
624 <tr>
625 <th>Computed value:
626 <td>specified value (except for initial and inherit)
627 </table>
629 <p>This property can be used on any element to control the text alignment of
630 the ruby text and ruby base contents relative to each other. It applies to all
631 the rubys in the element. For simple ruby, the alignment is applied to the
632 ruby child element whose content is shorter: either the <a
633 href="http://www.w3.org/TR/ruby/#rb"><samp>rb</samp></a> element or the <a
634 href="http://www.w3.org/TR/ruby/#rt"><samp>rt</samp></a> element [[RUBY]].
635 For complex ruby, the alignment is also applied to the
636 ruby child elements whose content is shorter: either the <samp>rb</samp>
637 element and/or one or two <samp>rt</samp> elements for each related ruby text
638 and ruby base element within the <samp>rtc</samp> and <samp>rbc</samp>
639 element.</p>
641 <p>Possible values:</p>
642 <p class="issue"><span class="issuehead">Issue: </span> Tony Graham has <a href="http://www.w3.org/Style/XSL/Group/FO/wiki/Ruby#Treat_CSS3_.22ruby-align.22_As_Shorthand.3F">suggested </a>that distribute-letter and distribute-space be values of a ruby-group-distribution property, and line-edge be moved to a ruby-alignment-edge property, and that the rest be gathered under a ruby-alignment property. And that ruby-align become a shorthand.</p>
643 <dl>
644 <dt><strong>auto</strong></dt>
645 <dd>The user agent determines how the ruby contents are aligned. This is
646 the initial value. The behavior recommended by [[JLREQ]] is for wide-cell ruby to be aligned in the 'distribute-space' mode:
647 <div class="figure">
648 <p><img class="example" width="145" height="91"
649 alt="Diagram of glyph layout in auto aligned ruby when ruby text is shorter than base"
650 src="images/ra-ds.gif" /><img class="example" width="145" height="91"
651 alt="Diagram of glyph layout in auto aligned ruby when ruby text is longer than base"
652 src="images/ra-ds-rb.gif" /></p>
653 <p><b>Figure 4.2.1</b>: Wide-cell text in 'auto' ruby alignment is
654 'distribute-space' justified</p>
655 </div>
656 <p>The recommended behavior for narrow-cell glyph ruby is to be
657 aligned in the 'center' mode.</p>
659 <div class="figure">
660 <p><img
661 alt="Diagram of glyph layout in auto aligned ruby when halfwidth ruby text is shorter than base"
662 class="example" width="145" height="91"
663 src="images/ra-c-h.gif" /><img
664 alt="Diagram of character layout in auto aligned ruby when ruby text is longer than narrow-width base"
665 class="example" width="145" height="91"
666 src="images/ra-c-rb-h.gif" /></p>
667 <p><b>Figure 4.2.2</b>: Narrow-width ruby text in 'auto' ruby alignment
668 is centered</p>
669 </div>
670 </dd>
671 <dt><strong>left</strong></dt>
672 <dd>The ruby text content is aligned with the start edge of the base.
674 <p class="issue"><span class="issuehead">Issue: </span> The i18n WG feels that start and left should not be synonymous, and proposed to drop left (there is no left/right in overhang)? See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20left/start+and+right/end&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">this thread</a>.</p>
676 <div class="figure">
677 <p><img
678 alt="Diagram of glyph layout in left aligned ruby when ruby text is shorter than base"
679 class="example" width="145" height="91" src="images/ra-l.gif" /><img
680 class="example" width="145" height="91"
681 alt="Diagram of glyph layout in left aligned ruby when ruby text is longer than base"
682 src="images/ra-l-rb.gif" /></p>
683 <p><b>Figure 4.2.3</b>: Start ruby alignment</p>
684 </div>
685 </dd>
686 <dt><strong>center</strong></dt>
687 <dd>The ruby text content is centered within the width of the base. If the
688 length of the base is smaller than the length of the ruby text, then the
689 base is centered within the width of the ruby text.
691 <div class="figure">
692 <p><img class="example" width="145" height="91"
693 alt="Diagram of glyph layout in center aligned ruby when ruby text is shorter than base"
694 src="images/ra-c.gif" /><img class="example" width="145" height="91"
695 alt="Diagram of glyph layout in center aligned ruby when ruby text is longer than base"
696 src="images/ra-c-rb.gif" /></p>
697 <p><b>Figure 4.2.4</b>: Center ruby alignment</p>
698 </div>
699 </dd>
700 <dt><strong>right</strong></dt>
701 <dd>The ruby text content is aligned with the end edge of the base.
702 <p class="issue"><span class="issuehead">Issue: </span> The i18n WG feels that end and right should not be synonymous, and proposed to drop right (there is no left/right in overhang)? See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20left/start+and+right/end&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">this thread</a>.</p>
703 <div class="figure">
704 <p><img class="example" width="145" height="91"
705 alt="Diagram of glyph layout in right aligned ruby when ruby text is shorter than base"
706 src="images/ra-r.gif" /><img class="example" width="145" height="91"
707 alt="Diagram of glyph layout in right aligned ruby when ruby text is longer than base"
708 src="images/ra-r-rb.gif" /></p>
709 <p><b>Figure 4.2.5</b>: End ruby alignment</p>
710 </div>
711 </dd>
712 <dt><strong>distribute-letter</strong></dt>
713 <dd>If the width of the ruby text is smaller than that of the base, then
714 the ruby text contents are evenly distributed across the width of the
715 base, with the first and last ruby text glyphs lining up with the
716 corresponding first and last base glyphs. If the width of the ruby text
717 is at least the width of the base, then the letters of the base are
718 evenly distributed across the width of the ruby text.
720 <div class="figure">
721 <p><img class="example" width="145" height="91"
722 alt="Diagram of glyph layout in distribute-letter aligned ruby when ruby text is shorter than base"
723 src="images/ra-dl.gif" /><img class="example" width="145" height="91"
724 alt="Diagram of glyph layout in distribute-letter aligned ruby when ruby text is longer than base"
725 src="images/ra-dl-rb.gif" /></p>
726 <p><b>Figure 4.2.6</b>: Distribute-letter ruby alignment</p>
727 </div>
728 </dd>
729 <dt><strong>distribute-space</strong></dt>
730 <dd>If the width of the ruby text is smaller than that of the base, then
731 the ruby text contents are evenly distributed across the width of the
732 base, with a certain amount of white space preceding the first and
733 following the last character in the ruby text. That amount of white
734 space is normally equal to half the amount of inter-character space of
735 the ruby text. If the width of the ruby text is at least the width of
736 the base, then the same type of space distribution applies to the base.
737 In other words, if the base is shorter than the ruby text, the base is
738 distribute-space aligned. This type of alignment
739 is described by [[JLREQ]].
740 <div class="figure">
741 <p><img class="example" width="145" height="91"
742 alt="Diagram of glyph layout in distribute-space aligned ruby when ruby text is shorter than base"
743 src="images/ra-ds.gif" /><img class="example" width="145" height="91"
744 alt="Diagram of glyph layout in distribute-space aligned ruby when ruby text is longer than base"
745 src="images/ra-ds-rb.gif" /></p>
746 <p><b>Figure 4.2.7</b>: Distribute-space ruby alignment</p>
747 </div>
748 </dd>
749 <dt><strong>line-edge</strong></dt>
750 <dd>If the ruby text is not adjacent to a line edge, it is aligned as in
751 'auto'. If it is adjacent to a line edge, then it is still aligned as in
752 auto, but the side of the ruby text that touches the end of the line is
753 lined up with the corresponding edge of the base. This type of alignment
754 is described by [[JLREQ]]. This type of alignment is
755 relevant only to the scenario where the ruby text is longer than the
756 ruby base. In the other scenarios, this is just 'auto'.
757 <div class="figure">
758 <p><img class="example" width="146" height="109"
759 alt="Diagram of glyph layout in line-edge aligned ruby when ruby text is shorter than base"
760 src="images/ra-le-l.gif" /><img class="example" width="146"
761 height="110"
762 alt="Diagram of glyph layout in line-edge aligned ruby when ruby text is longer than base"
763 src="images/ra-le-r.gif" /></p>
764 <p><b>Figure 4.2.8</b>: Line edge ruby alignment</p>
765 </div>
766 </dd>
767 </dl>
769 <p>For a complex ruby with spanning elements, one additional consideration is
770 required. If the spanning element spans multiple 'rows' (other rbc or rtc
771 elements), and the ruby alignment requires space distribution among the
772 'spanned' elements, a ratio must be determined among the 'columns' of spanned
773 elements. This ratio is computed by taking into consideration the widest
774 element within each column.</p>
776 <p>In the context of this property, the 'left' and 'right' values are
777 synonymous with the 'start' and 'end' values respectively. I.e. their meaning
778 is relative according to the text layout flow. Most of the other CSS
779 properties interpret 'left' and 'right' on an 'absolute' term. See Appendix A
780 of the <a href="#CSS3TEXT">CSS3 Text Module</a> for further details.</p>
782 <h3 id="rubyover">
783 Ruby overhanging: the 'ruby-overhang' property</h3>
785 <table class="propdef">
786 <tr>
787 <th>Name:
788 <td><dfn>ruby-overhang</dfn>
789 <tr>
790 <th>Value:
791 <td>auto | start | end | none
792 <tr>
793 <th>Initial:
794 <td>none
795 <tr>
796 <th>Applies to:
797 <td>the parent of elements with display: ruby-text
798 <tr>
799 <th>Inherited:
800 <td>yes
801 <tr>
802 <th>Percentages:
803 <td>N/A
804 <tr>
805 <th>Media:
806 <td>visual
807 <tr>
808 <th>Computed value:
809 <td>specified value (except for initial and inherit)
810 </table>
812 <p>This property determines whether, and on which side, ruby text is allowed
813 to partially overhang any adjacent text in addition to its own base, when the
814 ruby text is wider than the ruby base. Note that ruby text is never allowed to
815 overhang glyphs belonging to another ruby base. <span class="issue"><span class="issuehead">Issue: </span> This rule must be broken if we are to allow support for jukugo ruby.</span> Also the user agent is free to assume
816 a maximum amount by which ruby text may overhang adjacent text. The user agent may use
817 the [[JIS4051]] recommendation of using one ruby text character
818 length as the maximum overhang length. Detailed rules for how ruby text can overhang adjacent characters for Japanese are described by [[JLREQ]].</p>
820 <p>Possible values:</p>
821 <dl>
822 <dt><strong>auto</strong></dt>
823 <dd>The ruby text can overhang text adjacent to the base on either side. [[JLREQ]] and [[JIS4051]] specify the categories of characters that
824 ruby text can overhang. The user agent is free to follow those recommendations or specify its own classes of
825 characters to overhang. This is the initial value.
826 <div class="figure">
827 <p><img class="example" width="177" height="91"
828 alt="Diagram of glyph layout in overhanging ruby" src="images/ro-a.gif" /></p>
829 <p><b>Figure 4.3.1</b>: Ruby overhanging adjacent text</p>
830 </div>
831 </dd>
832 <dt><strong>start</strong></dt>
833 <dd>The ruby text can only overhang the text that precedes it. That means, for
834 example, that ruby cannot overhang text that is to the right of it in
835 horizontal LTR layout, and it cannot overhang text that is below it in
836 vertical-ideographic layout.
837 <div class="figure">
838 <p><img class="example" width="199" height="91"
839 alt="Diagram of glyph layout when ruby overhangs the preceding glyphs only"
840 src="images/ro-s.gif" /></p>
841 <p><b>Figure 4.3.2</b>: Ruby overhanging preceding text only</p>
842 </div>
843 </dd>
844 <dt><strong>end</strong></dt>
845 <dd>The ruby text can only overhang the text that follows it. That means, for
846 example, that ruby cannot overhang text that is to the left of it in
847 horizontal LTR layout, and it cannot overhang text that is above it in
848 vertical-ideographic layout.
849 <div class="figure">
850 <p><img class="example" width="198" height="91"
851 alt="Diagram of glyph layout when ruby overhangs the following characters only"
852 src="images/ro-e.gif" /></p>
853 <p><b>Figure 4.3.3</b>: Ruby overhanging following text only</p>
854 </div>
855 </dd>
856 <dt><strong>none</strong></dt>
857 <dd>The ruby text cannot overhang any text adjacent to its base, only its
858 own base.
860 <div class="figure">
861 <p><img class="example" width="220" height="91"
862 alt="Diagram of glyph layout in non-overhanging ruby"
863 src="images/ro-n.gif" /></p>
864 <p><b>Figure 4.3.4</b>: Ruby not allowed to overhang adjacent text</p>
865 </div>
866 </dd>
867 </dl>
869 <h3 id="rubyspan">
870 Ruby annotation spanning: the 'ruby-span' property</h3>
872 <table class="propdef">
873 <tr>
874 <th>Name:
875 <td><dfn>ruby-span</dfn>
876 <tr>
877 <th>Value:
878 <td>attr(x) | none
879 <tr>
880 <th>Initial:
881 <td>none
882 <tr>
883 <th>Applies to:
884 <td>elements with display: ruby-text
885 <tr>
886 <th>Inherited:
887 <td>no
888 <tr>
889 <th>Percentages:
890 <td>N/A
891 <tr>
892 <th>Media:
893 <td>visual
894 <tr>
895 <th>Computed value:
896 <td><number>
897 </table>
899 <p>This property controls the spanning behavior of annotation elements. </p>
901 <p class="note"><span class="note-label">Note:</span> A XHTML user agent may also use the <samp>rbspan</samp>
902 attribute to get the same effect.</p>
904 <p>Possible values:</p>
906 <dl>
907 <dt><strong>attr(x)</strong></dt>
908 <dd>The value of attribute 'x' as a string value. The string value is
909 evaluated as a <number> to determine the number of ruby base elements to be
910 spanned by the annotation element. If the <number> is '0', it is replaced by
911 '1'.The <number> is the computed value. </dd>
912 <dt>none</dt>
913 <dd>No spanning. The computed value is '1'.</dd>
914 </dl>
916 <p>The following example shows an XML example using the 'display' property
917 values associated with the 'ruby structure and the 'ruby-span' property</p>
918 <pre class="xml">myruby { display: ruby; }
919 myrbc { display: ruby-base-container; }
920 myrb { display: ruby-base; }
921 myrtc.before { display: ruby-text-container; ruby-position: before}
922 myrtc.after { display: ruby-text-container; ruby-position: after}
923 myrt { display: ruby-text; ruby-span: attr(rbspan); }
924 ...
925 <myruby>
926 <myrbc>
927 <myrb>10</myrb>
928 <myrb>31</myrb>
929 <myrb>2002</myrb>
930 </myrbc>
931 <myrtc class="before">
932 <myrt>Month</myrt>
933 <myrt>Day</myrt>
934 <myrt>Year</myrt>
935 </myrtc>
936 <myrtc class="after">
937 <myrt rbspan="3">Expiration Date</myrt>
938 </myrtc>
939 </myruby></pre>
941 <p class="issue"><span class="issuehead">Issue: </span> The i18n WG has requested the addition of a sample user agent default style sheet, as promised by Ruby Annotation section 3.4. See <a href="http://www.w3.org/Search/Mail/Public/advanced_search?keywords=&hdr-1-name=subject&hdr-1-query=[CSS3+Ruby]%20Default+stylesheet&hdr-2-name=from&hdr-2-query=&hdr-3-name=message-id&hdr-3-query=&index-grp=Member__FULL+Public__FULL&index-type=t&type-index=public-i18n-core%40w3.org&resultsperpage=20&sortby=date">this thread</a>.</p>
943 <h2 id="profiles">
944 Profiles</h2>
946 <p>There are two modules defined by this module:</p>
948 <p>CSS3 Simple Ruby model</p>
950 <p>CSS3 Complex Ruby model.</p>
952 <p>They both contain all the properties specified by this CSS chapter, i.e. <a
953 href="#rubyalign">'ruby-align'</a>, <a href="#rubyover">'ruby-overhang'</a>, <a href="#rubypos">'ruby-position'</a>
954 and <a href="#rubyspan">'ruby-span'</a>. They differ by the required
955 'display' property values. The Simple Ruby model requires the values: 'ruby',
956 'ruby-base' and 'ruby-text'. The Complex Ruby model requires in addition the
957 values: 'ruby-base-container' and 'ruby-text-container'.</p>
959 <h2 id="glossary">
960 Glossary</h2>
961 <dl>
962 <dt><a id="g-bopomofo"><strong><span
963 lang="zh">Bopomofo</span></strong></a></dt>
964 <dd>37 characters and 4 tone markings used as phonetics in Chinese,
965 especially standard Mandarin.</dd>
966 <dt><a id="g-hanja"><strong><span
967 lang="ko">Hanja</span></strong></a></dt>
968 <dd>Subset of the Korean writing system that utilizes ideographic
969 characters borrowed or adapted from the Chinese writing system. Also see
970 <a href="#g-kanji"><span lang="ja">Kanji</span></a>.</dd>
971 <dt><a id="g-hiragana"><strong><span
972 lang="ja">Hiragana</span></strong></a></dt>
973 <dd>Japanese syllabic script, or character of that script. Rounded and
974 cursive in appearance. Subset of the Japanese writing system, used together
975 with kanji and katakana. In recent times, mostly used to write Japanese
976 words when kanji are not available or appropriate, and word endings and
977 particles. Also see <a
978 href="#g-katakana"><span lang="ja">Katakana</span></a>.</dd>
979 <dt><a id="g-ideogram"><strong>Ideograph</strong></a></dt>
980 <dd>A character that is used to represent an idea, word, or word component,
981 in contrast to a character from an alphabetic or syllabic script. The most
982 well-known ideographic script is used (with some variation) in East Asia
983 (China, Japan, Korea,...).</dd>
984 <dt><a id="g-kana"><strong><span lang="ja">Kana</span></strong></a></dt>
985 <dd>Collective term for hiragana and katakana.</dd>
986 <dt><a id="g-kanji"><strong>Kanji</strong></a></dt>
987 <dd>Japanese term for ideographs; ideographs used in Japanese. Subset of the
988 Japanese writing system, used together with hiragana and katakana. Also see <a
989 href="#g-hanja"><span lang="ko">Hanja</span></a>.</dd>
990 <dt><a id="g-katakana"><strong><span
991 lang="ja">Katakana</span></strong></a></dt>
992 <dd>Japanese syllabic script, or character of that script. Angular in
993 appearance. Subset of the Japanese writing system, used together with
994 kanji and hiragana. In recent times, mainly used to write foreign words. Also see <a
995 href="#g-hiragana"><span lang="ja">Hiragana</span></a>.</dd>
996 <dt><a id="g-monoruby" name="g-monoruby"><strong>Mono-ruby</strong></a></dt>
997 <dd>In Japanese typography: Ruby associated with a single character of
998 the base text.</dd>
999 <dt><a id="g-ruby"><strong>Ruby</strong></a></dt>
1000 <dd>A run of text that appears in the vicinity of another run of text and
1001 serves as an annotation or a pronunciation guide for that text.</dd>
1002 </dl>
1004 <h2 id="conformance">
1005 Conformance</h2>
1007 <h3 id="conventions">
1008 Document conventions</h3>
1010 <p>Conformance requirements are expressed with a combination of
1011 descriptive assertions and RFC 2119 terminology. The key words “MUST”,
1012 “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”,
1013 “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this
1014 document are to be interpreted as described in RFC 2119.
1015 However, for readability, these words do not appear in all uppercase
1016 letters in this specification.
1018 <p>All of the text of this specification is normative except sections
1019 explicitly marked as non-normative, examples, and notes. [[!RFC2119]]</p>
1021 <p>Examples in this specification are introduced with the words “for example”
1022 or are set apart from the normative text with <code>class="example"</code>,
1023 like this:
1025 <div class="example">
1026 <p>This is an example of an informative example.</p>
1027 </div>
1029 <p>Informative notes begin with the word “Note” and are set apart from the
1030 normative text with <code>class="note"</code>, like this:
1032 <p class="note">Note, this is an informative note.</p>
1034 <h3 id="conformance-classes">
1035 Conformance classes</h3>
1037 <p>Conformance to CSS Ruby Module
1038 is defined for three conformance classes:
1039 <dl>
1040 <dt><dfn title="style sheet!!as conformance class">style sheet</dfn>
1041 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
1042 style sheet</a>.
1043 <dt><dfn>renderer</dfn></dt>
1044 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
1045 that interprets the semantics of a style sheet and renders
1046 documents that use them.
1047 <dt><dfn id="authoring-tool">authoring tool</dfn></dt>
1048 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
1049 that writes a style sheet.
1050 </dl>
1052 <p>A style sheet is conformant to CSS Ruby Module
1053 if all of its statements that use syntax defined in this module are valid
1054 according to the generic CSS grammar and the individual grammars of each
1055 feature defined in this module.
1057 <p>A renderer is conformant to CSS Ruby Module
1058 if, in addition to interpreting the style sheet as defined by the
1059 appropriate specifications, it supports all the features defined
1060 by CSS Ruby Module by parsing them correctly
1061 and rendering the document accordingly. However, the inability of a
1062 UA to correctly render a document due to limitations of the device
1063 does not make the UA non-conformant. (For example, a UA is not
1064 required to render color on a monochrome monitor.)
1066 <p>An authoring tool is conformant to CSS Ruby Module
1067 if it writes style sheets that are syntactically correct according to the
1068 generic CSS grammar and the individual grammars of each feature in
1069 this module, and meet all other conformance requirements of style sheets
1070 as described in this module.
1072 <h3 id="partial">
1073 Partial implementations</h3>
1075 <p>So that authors can exploit the forward-compatible parsing rules to
1076 assign fallback values, CSS renderers <strong>must</strong>
1077 treat as invalid (and <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore
1078 as appropriate</a>) any at-rules, properties, property values, keywords,
1079 and other syntactic constructs for which they have no usable level of
1080 support. In particular, user agents <strong>must not</strong> selectively
1081 ignore unsupported component values and honor supported values in a single
1082 multi-value property declaration: if any value is considered invalid
1083 (as unsupported values must be), CSS requires that the entire declaration
1084 be ignored.</p>
1086 <h3 id="experimental">
1087 Experimental implementations</h3>
1089 <p>To avoid clashes with future CSS features, the CSS2.1 specification
1090 reserves a <a href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
1091 syntax</a> for proprietary and experimental extensions to CSS.
1093 <p>Prior to a specification reaching the Candidate Recommendation stage
1094 in the W3C process, all implementations of a CSS feature are considered
1095 experimental. The CSS Working Group recommends that implementations
1096 use a vendor-prefixed syntax for such features, including those in
1097 W3C Working Drafts. This avoids incompatibilities with future changes
1098 in the draft.
1099 </p>
1101 <h3 id="testing">
1102 Non-experimental implementations</h3>
1104 <p>Once a specification reaches the Candidate Recommendation stage,
1105 non-experimental implementations are possible, and implementors should
1106 release an unprefixed implementation of any CR-level feature they
1107 can demonstrate to be correctly implemented according to spec.
1109 <p>To establish and maintain the interoperability of CSS across
1110 implementations, the CSS Working Group requests that non-experimental
1111 CSS renderers submit an implementation report (and, if necessary, the
1112 testcases used for that implementation report) to the W3C before
1113 releasing an unprefixed implementation of any CSS features. Testcases
1114 submitted to W3C are subject to review and correction by the CSS
1115 Working Group.
1117 <p>Further information on submitting testcases and implementation reports
1118 can be found from on the CSS Working Group's website at
1119 <a href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
1120 Questions should be directed to the
1121 <a href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
1122 mailing list.
1124 <h2 class=no-num id="acknowledgments">
1125 Acknowledgments</h2>
1127 <p>This specification would not have been possible without the help from:</p>
1129 <p>Stephen Deach, Martin Dürst, Hideki Hiura(<span lang="ja">樋浦 秀樹</span>), Masayasu Ishikawa(<span lang="ja">石川
1130 雅康</span>), Chris
1131 Pratley, Takao Suzuki(<span lang="ja">鈴木 孝雄</span>), Frank Yung-Fong Tang, Chris Thrasher, Masafumi Yabe<span lang="ja">家辺
1132 勝文</span>), Steve Zilles.</p>
1134 <h2 class=no-num id="references">
1135 References</h2>
1137 <h3 class="no-num" id="normative-references">
1138 Normative references</h3>
1139 <!--normative-->
1141 <h3 class="no-num" id="other-references">
1142 Other references</h3>
1143 <!--informative-->
1145 <h2 class="no-num" id="index">
1146 Index</h2>
1147 <!--index-->
1149 <h2 class="no-num" id="property-index">
1150 Property index</h2>
1151 <!-- properties -->
1153 </body>
1154 </html>
1155 <!-- Keep this comment at the end of the file
1156 Local variables:
1157 mode: sgml
1158 sgml-declaration:"~/SGML/HTML4.decl"
1159 sgml-default-doctype-name:"html"
1160 sgml-minimize-attributes:t
1161 sgml-nofill-elements:("pre" "style" "br")
1162 sgml-live-element-indicator:t
1163 sgml-omittag:nil
1164 sgml-shorttag:nil
1165 sgml-namecase-general:t
1166 sgml-general-insert-case:lower
1167 sgml-always-quote-attributes:t
1168 sgml-indent-step:nil
1169 sgml-indent-data:t
1170 sgml-parent-document:nil
1171 sgml-exposed-tags:nil
1172 sgml-local-catalogs:nil
1173 sgml-local-ecat-files:nil
1174 End:
1175 -->
