css-ruby/Overview.src.html@d0cb61f45f33
css-ruby/Overview.src.html
Fri, 13 Sep 2013 14:36:46 -0700
- author
- fantasai <fantasai.cvs@inkedblade.net>
- date
- Fri, 13 Sep 2013 14:36:46 -0700
- changeset 9174
- d0cb61f45f33
- parent 9173
- a509cde54544
- child 9177
- dbc00077efcc
- permissions
- -rw-r--r--
[css-ruby] Fix more markup errors
1 <!DOCTYPE html>
2 <!--
4 Issues:
5 bidi
6 box layout/sizing
7 clean up inter-character vs. parallel layout requirements
9 Redo all examples with consistent font. (M+ 2p?)
11 -->
12 <html lang="en">
13 <head>
14 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
15 <title>CSS Ruby Module Level 1</title>
16 <link rel=contents href="#contents">
17 <link rel=index href="#index">
18 <link rel="stylesheet" type="text/css" href="../default.css">
19 <link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
20 <link rel="stylesheet" type="text/css" href="http://www.w3.org/StyleSheets/TR/W3C-[STATUS].css">
21 </head>
23 <body class="h-entry">
25 <div class="head">
26 <!--logo-->
28 <h1 class="p-name">CSS Ruby Module Level 1</h1>
30 <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>
31 <dl>
32 <dt>This version:
33 <dd><a class="u-url" href="[VERSION]">[VERSION]</a>
35 <dt>Latest version:
36 <dd><a href="http://www.w3.org/TR/[SHORTNAME]/">http://www.w3.org/TR/css3-ruby/</a>
38 <dt>Editor's draft:
39 <dd><a href="http://dev.w3.org/csswg/[SHORTNAME]/">http://dev.w3.org/csswg/[SHORTNAME]/</a>
40 (<a href="https://dvcs.w3.org/hg/csswg/log/tip/[SHORTNAME]/Overview.src.html">change log</a>)
42 <dt>Previous version:
43 <dd><a href="http://www.w3.org/TR/2011/WD-css3-ruby-20110630/">
44 http://www.w3.org/TR/2011/WD-css3-ruby-20110630/</a>
46 <dt>Issue Tracking:</dt>
47 <dd><a rel="issues" href="http://www.w3.org/Style/CSS/Tracker/products/FIXME">http://www.w3.org/Style/CSS/Tracker/products/FIXME</a>
49 <dt>Feedback:</dt>
50 <dd><a href="mailto:www-style@w3.org?subject=%5BSHORTNAME%5D%20feedback"
51 >www-style@w3.org</a>
52 with subject line “<kbd>[[SHORTNAME]]
53 <var>… message topic …</var></kbd>”
54 (<a rel="discussion" href="http://lists.w3.org/Archives/Public/www-style/"
55 >archives</a>)
57 <dt>Editors:
58 <dd class="p-author h-card vcard">
59 <a class="p-name fn u-url url" rel="author"
60 href="http://fantasai.inkedblade.net/contact">Elika J. Etemad</a>,
61 <a class="p-org org h-org" href="http://www.mozilla.org/">Mozilla</a>
62 <dd class="p-author h-card vcard">
63 <a class="p-name fn u-url url" rel="author"
64 href="mailto:koji.a.ishii@mail.rakuten.com">Koji Ishii</a>,
65 <span class="p-org org">Rakuten, Inc.</span>
66 <dd class="p-author h-card vcard">
67 <a class="p-name fn u-url url" rel="author"
68 href="mailto:ishida@w3.org">Richard Ishida</a>,
69 <span class="p-org org">W3C</span>
71 <dt>Former editors:
72 <dd>Michel Suignard, Microsoft
73 <dd>Marcin Sawicki, Microsoft
74 </dl>
76 <!--copyright-->
78 <hr title="Separator for header">
79 </div>
81 <h2 class="no-num no-toc" id="abstract">Abstract</h2>
83 <p>
84 <span class="p-summary">
85 “Ruby” are short runs of text alongside the base text,
86 typically used in East Asian documents to indicate pronunciation
87 or to provide a short annotation.
88 This module describes the rendering model and formatting controls
89 related to displaying ruby annotations in CSS.
90 </span>
92 <a href="http://www.w3.org/TR/CSS/">CSS</a> is a language for describing
93 the rendering of structured documents (such as HTML and XML) on screen, on
94 paper, in speech, etc.
96 <h2 class="no-num no-toc" id="status">Status of this document</h2>
98 <!--status-->
100 <p>The following features are at risk: …
102 <h2 class="no-num no-toc" id="contents">
103 Table of Contents</h2>
105 <!--toc-->
107 <h2 id="intro">
108 Introduction</h2>
110 <p><em>This section is not normative.</em>
112 <h3 id="placement">
113 Module interactions</h3>
115 <p>This module extends the inline box model of CSS Level 2 [[!CSS21]]
116 to support ruby.
118 <p>None of the properties in this module apply to the <code>::first-line</code> or
119 <code>::first-letter</code> pseudo-elements.
121 <h3 id="values">
122 Values</h3>
124 <p>This specification follows the
125 <a href="http://www.w3.org/TR/CSS21/about.html#property-defs">CSS property
126 definition conventions</a> from [[!CSS21]]. Value types not defined in
127 this specification are defined in CSS Level 2 Revision 1 [[!CSS21]].
128 Other CSS modules may expand the definitions of these value types: for
129 example [[CSS3VAL]], when combined with this module, expands the
130 definition of the <var><length></var> value type as used in this specification.</p>
132 <p>In addition to the property-specific values listed in their definitions,
133 all properties defined in this specification also accept the
134 <a href="http://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>
135 keyword as their property value. For readability it has not been repeated
136 explicitly.
138 <h3 id="diagram-conventions">
139 Diagram conventions</h3>
141 <p>Many typographical conventions in East Asian typography depend
142 on whether the character rendered is wide (CJK) or narrow (non-CJK).
143 There are a number of illustrations in this document
144 for which the following legend is used:
146 <dl>
147 <dt><img alt="Symbolic wide-cell glyph representation" width="39" height="39" src="images/fullwidth.gif">
148 <dd>Wide-cell glyph (e.g. Han) that is the <var>n</var>th character in the text run.
149 They are typically sized to 50% when used as annotations.
150 <dt><img alt="Symbolic narrow-cell glyph representation" width="19" height="39" src="images/halfwidth.gif">
151 <dd>Narrow-cell glyph (e.g. Roman) which is the <var>n</var>th glyph in the text run.
152 </dl>
154 <p>The orientation which the above symbols assume in the diagrams
155 corresponds to the orientation that the glyphs they represent
156 are intended to assume when rendered by the user agent.
157 Spacing between these characters in the diagrams is incidental,
158 unless intentionally changed to make a point.
160 <h3 id="ruby-def">
161 What is ruby?</h3>
163 <p><dfn>Ruby</dfn> is the commonly-used name for a run of text
164 that appears alongside another run of text (referred to as the “base”)
165 and serves as an annotation or a pronunciation guide associated with that run of text.
167 <p>The following figures show two examples of Ruby,
168 a simple case and one with more complicated structure.
170 <div class="example">
171 <p>In this first example, a single annotation is used to annotate the base text.
172 <div class="figure">
173 <p><img src="images/licence.png"
174 alt="Example of ruby applied on top of a Japanese expression">
175 <p class="caption">Example of ruby used in Japanese (simple case)
176 </div>
177 <p>In Japanese typography, this case is sometimes called
178 <i lang="ja">taigo</i> ruby or group-ruby (per-word ruby),
179 because the annotation as a whole is associated
180 with multi-character word (as a whole).
181 </div>
183 <div class="example">
184 <p>In this second example,
185 two levels of annotations are attached to a base sequence:
186 the hiragana characters on top refer to the pronunciation of each of the base kanji characters,
187 while the words “Keio” and “University” on the bottom are annotations describing the English translation.
188 <div class="figure">
189 <p><img src="images/ruby-univ.gif"
190 alt="Example showing complex ruby with annotation text over and under the base characters">
191 <p class="caption">Complex ruby with annotation text over and under the base characters
192 </div>
193 <p>
194 <p>Notice that to allow correct association between the hiragana characters and
195 their corresponding Kanji base characters,
196 the spacing between these Kanji characters is adjusted.
197 (This happens around the fourth Kanji character in the figure above.)
198 To avoid variable spacing between the Kanji characters in the example above
199 the hiragana annotations can be styled as a <i>collapsed annotation</i>,
200 which will look more like the group-ruby example earlier.
201 However because the base-annotation pairings are recorded in the ruby structure,
202 if the text breaks across lines, the annotation characters will stay
203 correctly paired with their respective base characters.
204 </div>
206 <p><i>Ruby</i> formatting as used in Japanese is described in JIS X-4051 [[JIS4051]] (in Japanese)
207 and in Requirements for Japanese Text Layout [[JLREQ]] (in English and Japanese)].
208 In HTML, ruby structure and markup to represent it is described
209 in the Ruby Markup Extension specification.
210 This module describes the CSS rendering model
211 and formatting controls relevant to ruby layout of such markup.
213 <h2 id="ruby-model">
214 Ruby Formatting Model</h2>
216 <p>The CSS ruby model is based on
217 the <a href="http://darobin.github.io/html-ruby/">HTML Ruby Markup Extension</a>
218 and <a href="http://www.w3.org/TR/ruby/">XHTML Ruby Annotation Recommendation</a> [[RUBY]].
219 In this model, a ruby structure consists of
220 one or more <dfn>ruby base</dfn> elements representing the base (annotated) text,
221 associated with one or more levels of <dfn>ruby annotation</dfn> elements representing the annotations.
222 The structure of ruby is similar to that of a table:
223 there are “rows” (the base text level, each annotation level)
224 and “columns” (each <i>ruby base</i> and its corresponding <i>ruby annotations</i>).
226 <p>Consecutive bases and annotations are grouped together into <dfn>ruby segments</dfn>.
227 Within a <i>ruby segment</i>, a <i>ruby annotation</i> may span multiple <i>ruby bases</i>.
229 <p class="note">In HTML, a single <code><ruby></code> element may contain multiple <i>ruby segments</i>.
230 (In the XHTML Ruby model, a single <code><ruby></code> element can only contain one <i>ruby segment</i>.)
232 <h3 id="ruby-display">
233 Ruby-specific 'display' property values</h3>
235 <p>For document languages (such as XML applications) that do not have pre-defined ruby elements,
236 authors must map document language elements to ruby elements;
237 this is done with the 'display' property.
239 <table class="propdef">
240 <tr>
241 <th>Name:
242 <td>display
243 <tr>
244 <th><a href="#values">New Values</a>:
245 <td>ruby | ruby-base | ruby-text | ruby-base-container | ruby-text-container
246 </table>
248 <p>The following new 'display' values assign ruby layout roles to an arbitrary element:
250 <dl>
251 <dt>''ruby''
252 <dd>Specifies that an element generates a <dfn title="ruby container | ruby container box">ruby container box</dfn>.
253 (Corresponds to HTML/XHTML <code><ruby></code> elements.)
254 <dt>''ruby-base''
255 <dd>Specifies that an element generates a <dfn title="ruby base box | ruby base">ruby base box</dfn>.
256 (Corresponds to HTML/XHTML <code><rb></code> elements.)
257 <dt>''ruby-text''
258 <dd>Specifies that an element generates a <dfn title="ruby annotation box | ruby annotation">ruby annotation box</dfn>.
259 (Corresponds to HTML/XHTML <code><rt></code> elements.)
260 <dt>''ruby-base-container''
261 <dd>Specifies that an element generates a <dfn title="ruby base container box | ruby base container">ruby base container box</dfn>.
262 (Corresponds to XHTML <code><rbc></code> elements; always implied in HTML.)
263 <dt>''ruby-text-container''
264 <dd>Specifies that an element generates a <dfn title="ruby annotation container box | ruby annotation container">ruby annotation container box</dfn>.
265 (Corresponds to HTML/XHTML <code><ruby></code> elements.)
266 </dl>
268 <h3 id="box-fixup">
269 Anonymous Ruby Box Generation</h3>
271 <p>The CSS model does not require that the document language
272 include elements that correspond to each of these components.
273 Missing parts of the structure are implied through the anonymous box generation rules
274 <a href="http://www.w3.org/TR/CSS21/tables.html#anonymous-boxes">similar to those used to normalize tables</a>. [[!CSS21]]
276 <ol>
277 <li>Any in-flow block-level boxes directly contained by a
278 <i>ruby container</i>,
279 <i>ruby base container</i>,
280 <i>ruby annotation container</i>,
281 <i>ruby base box</i>,
282 or <i>ruby annotation box</i>
283 are forced to be inline-level boxes,
284 and their 'display' value computed accordingly.
285 For example,
286 the 'display' property of an in-flow element with ''display: block''
287 parented by an element with ''display: ruby-text''
288 computes to ''inline-block''.
289 This computation occurs after any intermediary anonymous-box fixup
290 (such as that required by internal table elements).
292 <li>Any consecutive sequence of <i>ruby bases</i> not parented by a <i>ruby base container</i>
293 is wrapped in an anonymous <i>ruby base container</i>.
294 Similarly, any consecutive sequence of <i>ruby annotations</i> not parented by a <i>ruby annotation container</i>
295 is wrapped in an anonymous <i>ruby annotation container</i>.
297 <li>Within each <i>ruby base container</i>,
298 each sequence of inline-level boxes is wrapped in an anonymous <i>ruby base box</i>.
299 Similarly, within each <i>ruby annotation container</i>,
300 each sequence of inline-level boxes is wrapped in an anonymous <i>ruby annotation box</i>.
302 <li>A sequence of <i>ruby base containers</i> and/or <i>ruby annotation containers</i>
303 not parented by a <i>ruby container</i>
304 is wrapped in an anonymous <i>ruby container</i>.
305 </ol>
307 <p>At this point, all ruby layout structures are properly parented,
308 and the UA can start to associate bases with their annotations.
310 <p class="note">
311 Note that the UA is not required to create any of these anonymous boxes in its internal structures,
312 as long as pairing and layout behaves as if they existed.
314 <h3 id="pairing">
315 Ruby Pairing and Annotation Levels</h3>
317 <p>Within a ruby structure,
318 each <i>ruby base</i> is associated with <i>ruby annotations</i>
319 and vice versa.
320 A <i>ruby base</i> can be associated with at most one <i>ruby annotation</i> per annotation level.
321 If there are multiple annotation levels, it can therefore be associated with multiple <i>ruby annotations</i>.
322 A <i>ruby annotation</i> is associated with one or more <i>ruby bases</i>;
323 annotations can span multiple bases.
325 <p><dfn>Annotation pairing</dfn> is the process of associating
326 <i>ruby annotations</i> with <i>ruby bases</i>.
328 <ol>
329 <li>
330 <p>First, the ruby structure is divided into <i>ruby segments</i>,
331 each consisting of a single <i>ruby base container</i>
332 followed by one or more <i>ruby annotation containers</i>.
333 If the first child of a <i>ruby container</i> is a <i>ruby annotation container</i>,
334 an anonymous, empty <i>ruby base container</i> is assumed to exist before it.
335 Similarly, if the <i>ruby container</i> contains consecutive <i>ruby base containers</i>,
336 anonymous, empty <i>ruby annotation containers</i> are assumed to exist between them.
337 The <i>ruby base container</i> in each segment is thus associated
338 with each of the <i>ruby annotation containers</i> in that segment.
340 <p>Each <i>ruby annotation containers</i> in a <i>ruby segment</i>
341 represents one <dfn title="annotation level | level">level</dfn> of annotation:
342 the first one represents the first level of annotation,
343 the second one represents the second level of annotation,
344 and so on.
346 <li>Within each <i>ruby segment</i>,
347 each <i>ruby base box</i> in the <i>ruby base container</i>
348 is paired with one <i>ruby annotation box</i>
349 from each <i>ruby annotation container</i> in its <i>ruby segment</i>.
350 If there are not enough <i>ruby annotations</i> in a <i>ruby annotation container</i>,
351 the last one is associated with any excess <i>ruby bases</i>.
352 (If there are not any in the <i>ruby annotation container</i>, an anonymous empty one is assumed to exist.)
353 If there are not enough <i>ruby bases</i>,
354 any remaining <i>ruby annotations</i> are assumed to be associated
355 with empty, anonymous bases inserted at the end of the <i>ruby base container</i>.
357 <p>If an implementation supports ruby markup with explicit spanning
358 (e.g. XHTML Complex Ruby Annotations),
359 it must adjust the pairing rules to pair spanning annotations to multiple bases
360 appropriately.
361 </ol>
363 <p>A this point, ruby “columns” are defined,
364 each represented by a single <i>ruby base</i>
365 and associated with one <i>ruby annotation</i> (possibly an empty, anonymous one)
366 from each <i>annotation level</i>.
368 <h4 id="nested-pairing">
369 Nested Ruby</h4>
371 <p>When <i>ruby containers</i> are nested,
372 pairing begins with the deepest <i>ruby container</i>,
373 then expands out,
374 treating each <i>ruby container</i> nested within another <i>ruby container</i>
375 essentially as a single <i>ruby base</i> in the outer <i>ruby container</i>,
376 and associating each <i>ruby annotation</i>
377 paired with the nested <i>ruby container</i>
378 as being associated with (spanning) all of its <i>ruby bases</i>.
380 <p>Using nested <i>ruby containers</i> thus allows the representation
381 of complex spanning relationships.
383 <p class="issue">This has to be Level 1 because HTML5 allows it, so we have to handle it. Yay HTML5.
385 <h3 id="autohide">
386 Autohiding Annotations</h3>
388 <p>If a <i>ruby annotation</i> has the exact same text content as its base,
389 it is <dfn title="hidden ruby annotation | hidden annotation">hidden</dfn>.
390 Hiding a <i>ruby annotation</i> does not affect annotation pairing
391 or the block-axis positioning of boxes in other <i>levels</i>.
392 However the <i>hidden annotation</i> is not visible,
393 and it has no impact on layout
394 other than to separate adjacent sequences of <i>ruby annotation boxes</i> within its level,
395 as if they belonged to separate segments
396 and the <i>hidden annotation</i>’s base were not a <i>ruby base</i> but an intervening inline.
398 <div class="example">
399 <p>This is to allow correct inlined display of annotations
400 for Japanese words that are a mix of kanji and hirangana.
401 For example, the word <i>振り仮名</i> should be inlined as
402 <p class="figure">振り仮名(ふりがな)
403 <p>and therefore marked up as
404 <pre>
405 <!-- --><ruby>
406 <!-- --> <rb>振</rb><rb>り</rb><rb>仮</rb><rb>名</rb>
407 <!-- --> <rp>(</rp><rt>ふ</rt><rt>り</rt><rt>が</rt><rt>な</rt><rp>)</rp>
408 <!-- --><ruby></pre>
409 <p>However, when displayed as ruby, the “り” should be hidden
410 <div class="figure">
411 <p><img src="images/furigana-separate.png"
412 alt="Hiragana annotations for 振り仮名 appear, each above its base character.">
413 <p class="caption">Hiragana ruby for 振り仮名
414 </div>
415 </div>
417 <p class="note">
418 Future levels of CSS Ruby may add controls for this,
419 but in this level it is always forced.
421 <p>The content comparison for this auto-hiding behavior
422 takes place prior to white space collapsing
423 and ignores elements (considers only the <code>textContent</code> of the boxes).
424 <p class="issue">Is before or after white space collapsing easier? We should do whatever is easier, as it really doesn't matter much which way to go.
426 <h3 id="white-space">
427 White Space</h3>
429 <p><i>Collapsible</i> white space within a ruby structure is discarded
430 <ul>
431 <li>at the beginning and end of a <i>ruby container</i>, <i>ruby annotation container</i>, or <i>ruby base container</i>,
432 <li>at the beginning/end of a <i>ruby annotation box</i> or <i>ruby base box</i> if white space is not its only contents,
433 <li>between a <i>ruby base container</i> and its following <i>ruby annotation container</i>,
434 <li>between <i>ruby annotation containers</i>.
435 </ul>
437 <p>Between <i>ruby segments</i>, between <i>ruby bases</i>, and between <i>ruby annotations</i>, however,
438 white space is not discarded.
440 <p>Where undiscarded white space is <i>collapsible</i>, it will collapse
441 following the standard <a href="http://www.w3.org/TR/css3-text/#white-space-rules">white space processing rules</a>. [[!CSS3TEXT]]
442 For <i>collapsible</i> white space between <i>ruby segments</i>, however,
443 the contextual text for determining collapsing behavior is given by the <i>ruby bases</i> on either side,
444 not the text on either side of the white space in the source document.
446 <div class="note">
447 <p>Note that the white space processing rules
448 cause a white space sequence containing a <i>segment break</i> (such as a line feed)
449 to <a href="http://www.w3.org/TR/css3-text/#line-break-transform">collapse to nothing</a> between CJK characters.
450 This means that CJK ruby can safely use white space for indentation of the ruby markup.
451 For example, the following markup will display without any spaces:
452 <pre>
453 <!-- --><ruby>
454 <!-- --> <rb>東</rb><rb>京</rb>
455 <!-- --> <rt>とう</rt><rt>きょう</rt>
456 <!-- --></ruby></pre>
457 <p>However, white space that does not contain a <i>segment break</i> does not collapse completely away,
458 so this markup will display with a space between the first and second ruby pairs:
459 <pre>
460 <!-- --><ruby>
461 <!-- --> <rb>東</rb> <rb>京</rb>
462 <!-- --> <rt>とう</rt> <rt>きょう</rt>
463 <!-- --></ruby></pre>
464 </div>
466 <p>Any preserved white space is then wrapped in an anonymous box belonging to
467 the <i>ruby base container</i> (if between <i>ruby bases</i>),
468 <i>ruby annotation container</i> (if between <i>ruby annotations</i>),
469 or <i>ruby container</i> (if between <i>ruby segments</i>).
470 In the latter case, the text is considered part of the <i>base level</i>.
471 Such anonynmous boxes do not take part in pairing.
472 They merely ensure separation between adjacent bases/annotations.
474 <p class="issue">Specify how these anonymous white space boxes impact layout.
476 <div class="example">
477 <p>These rules allow ruby to be used with space-separated scripts such as Latin.
478 For example,
479 <pre>
480 <!-- --><ruby>
481 <!-- --> <rb>W</rb><rb>W</rb><rb>W</rb>
482 <!-- --> <rt>World</rt> <rt>Wide</rt> <rt>Web</rt>
483 <!-- --></ruby></pre>
484 <p>They also ensure that annotated white space is preserved. For example,
485 <pre>
486 <!-- --><ruby>
487 <!-- --> <rb>Aerith</rb><rb> </rb><rb>Gainsboro</rb>
488 <!-- --> <rt>エアリス</rt><rt>・</rt><rt>ゲインズブール</rt>
489 <!-- --></ruby></pre>
490 </div>
492 <h3 id="ruby-layout">
493 Ruby layout</h3>
495 <p>When a ruby structure is laid out,
496 its base level is laid out on the line,
497 aligned according to its 'vertical-align' property
498 exactly as if its <i>bases</i> were a regular sequence of <i>inline</i> boxes.
499 Each <i>ruby base container</i> is sized and positioned
500 to contain exactly the full height of its <i>ruby bases</i>.
502 <p><i>Ruby annotations</i> associated with the base level
503 are then positioned with respect to their <i>ruby base boxes</i>
504 according to the applicable 'ruby-position' values.
505 <i>Ruby annotations</i> within a level (within a single <i>ruby container</i>)
506 are aligned to each other as if they were inline boxes
507 participating in the same inline formatting context.
508 Each <i>ruby annotation container</i> is sized and positioned
509 to contain exactly the full height of its <i>ruby annotations</i>.
511 <p>A ruby container (or fragment thereof)
512 measures as wide as the content of its widest level.
513 Similarly, <i>ruby base boxes</i> and <i>ruby annotation boxes</i>
514 within a ruby “column” have the measure of the widest content in that “column”.
515 In the case of spanning <i>annotations</i>
516 (whether actually spanning or pretending to span per 'ruby-collapse'),
517 the measures of the <i>ruby annotation box</i> and
518 the sum of its associated <i>ruby base boxes</i> must match.
520 <p>How the extra space is distributed
521 when ruby content is narrower than the measure of its box
522 is specified by the 'ruby-align' property.
524 <h4 id="inter-character-layout">
525 Inter-character ruby layout</h4>
527 <p>Inter-character annotations have special layout.
528 When 'ruby-position' indicates ''inter-character'' annotations,
529 the affected <i>annotation boxes</i>
530 are spliced into and measured as part of the layout of the base level.
531 The <i>ruby base container</i> must be sized to include both the <i>base boxes</i>
532 as well as the ''inter-character'' <i>annotation boxes</i>.
533 The affected <i>ruby annotation container</i> is similarly sized
534 so that its content box coincides with that of the <i>ruby base container</i>.
536 <p>For the purpose of laying out other levels of annotations,
537 an ''inter-character'' annotation effectively becomes part of its base.
538 <span class="issue">Or should it become a quasi-base between two bases?</span>
539 A spanning ''inter-character'' annotation is placed after
540 all the bases that it spans.
542 <h3 id="box-style">
543 Styling Ruby Boxes</h3>
545 <p>In most respects, ruby boxes can be styled similar to inline boxes.
546 However, the UA is not required to support
547 any of the box properties (borders, margins, padding),
548 any of the background properties or outline properties,
549 or any other property that illustrates the bounds of the box
550 on <i>ruby base container boxes</i>, <i>ruby annotation container boxes</i>,
551 or <a href="#nested-pairing">ruby-internal <i>ruby container boxes</i></a>.
552 The UA may implement these boxes simply as abstractions for inheritance
553 and control over the layout of their contents.
555 <p class="issue">
556 Alternatively... use margins to control offsets?
557 Or could line-height be adequate? Its centering behavior can be awkward.
559 <h3 id="line-breaks">
560 Ruby box and line breaking</h3>
562 <p>When there is not enough space for an entire <i>ruby container</i> to fit on the line,
563 the ruby may be broken wherever all levels simultaneously allow a break.
564 Ruby most often breaks between base-annotation sets,
565 but if the line-breaking rules allow it, can also break within a <i>ruby base</i>
566 (and, in parallel, its associated <i>annotation boxes</i>).
568 <p>Whenever ruby breaks across lines, <i>ruby annotations</i> must stay
569 with their respective <i>bases</i>.
570 The line <em>must not</em> break between a <i>ruby base</i> and its <i>annotations</i>,
571 even in the case of ''inter-character'' <i>annotations</i>.
573 <div class="figure">
574 <img src="images/r-break-b.gif"
575 alt='Diagram showing the line breaking opportunity in a "Bopomofo" ruby'>
576 <p class="caption">''inter-character'' ruby line breaking opportunity
577 </div>
579 <h4 id="break-between">
580 Breaking between bases</h4>
582 <p>In typical cases, <i>ruby base boxes</i> and <i>ruby annotation boxes</i>
583 are styled to forbid internal line wrapping and do not contain forced breaks.
584 (See <a href="#default-stylesheet">Appendix A</a>.)
585 In such cases the <i>ruby container</i> can only break between adjacent <i>ruby bases</i>,
586 and only if no <i>ruby annotations</i> span those <i>ruby bases</i>.
588 <div class="figure">
589 <p><img src="images/r-break-a.gif"
590 alt="Diagram showing the line breaking opportunity in a complex ruby">
591 <p class="caption">Ruby line breaking opportunity
592 </div>
594 <p>Whether ruby can break between two adjacent <i>ruby bases</i>
595 is controlled by normal line-breaking rules for the base text,
596 exactly as if the <i>ruby bases</i> were adjacent <i>inline</i> boxes.
597 (The annotations are ignored when determining soft wrap opportunities for the base level.)
599 <div class="example">
600 <p>For example, if two adjacent ruby bases are “蝴” and “蝶”,
601 the line may break between them,
602 because lines are normally allowed to break between two Han characters.
603 However, if 'word-break' is ''keep-all'', that line break is forbidden.
604 <pre><ruby>蝴<rt>hú</rt>蝶<rt>dié</rt></pre>
605 </div>
607 <p>Inter-base white space is significant for evaluating line break opportunities between <i>ruby bases</i>.
608 As with white space between inlines, it collapses when the line breaks there.
609 Similarly, annotation white space is also trimmed at a line break.
611 <div class="example">
612 <p>For example, given the following markup:
613 <pre><ruby><rb>one</rb> <rb>two</rb> <rt>1</rt> <rt>2</rt></ruby></pre>
614 <p>Due to the space, the line may break between “one” and “two“.
615 If the line breaks there, that space—and the space between “1” and “2”—disappears,
616 in accordance with standard CSS white space processing rules. [[CSS3TEXT]]
617 </div>
619 <h4 id="break-within">
620 Breaking within bases</h4>
622 <p>For longer base texts, it is sometimes appropriate to allow breaking within a base-annotation pair.
623 For example, if an English sentence is annotated with its Japanese translation,
624 allowing the text to wrap allows for reasonable line breaking behavior in the paragraph.
626 <p class="issue">
627 Insert scanned example so people don't think this is just the ramblings of an insane spec-writer.
629 <p>Line-breaking within a <i>ruby base</i> is only allowed if the 'white-space' property
630 of the <i>ruby base</i> and all its parallel <i>annotations</i> allow it,
631 and there exists a <i>soft wrap opportunity</i> <em>within</em> (i.e. not at the start or end)
632 the content of each base/annotation box.
633 Since there is no structural correspondance between fragments of content
634 within <i>ruby bases</i> and <i>annotations</i>,
635 the UA may break at any set of opportunities;
636 but it is recommended that the UA attempt to proportionally balance
637 the amount of content inside each fragment.
639 <p>There are no line breaking opportunities within ''inter-character'' <i>annotations</i>.
641 <p>Ruby alignment takes place within each fragment, after line-breaking.
643 <h3 id="ruby-bidi">
644 Bidi Reordering</h3>
646 <p class="issue">
647 Constraints:
648 Text within a ruby base must remain contiguous,
649 and bases belonging to a single annotation must remain contiguous.
650 Still figuring out exactly to enforce these limitations in a sensible manner.
652 <!--
654 <p>The Unicode bidirectional algorithm orders logically-stored text for visual presentation
655 when characters from scripts of opposing directionalities are mixed
656 within a single paragraph.
657 (See [[CSS3-WRITING-MODES]] for a more in-depth discussion of bidirectional text in CSS.)
658 Bidi reordering of ruby-annotation pairs is controlled by the ordering of the base text, as follows:
660 <h4 id="bidi-B">Proposal A</h4>
662 <p class="note">This proposal is simpler, but will require more frequent tagging of mixed-directionality content.
664 <p>To avoid the interference of the <i>annotations</i> in the ordering of base text,
665 all annotations are ignored for the purpose of resolving neutral characters in the base level.
667 <p>To preserve the correspondance of <i>ruby annotations</i>
668 to their respective <i>ruby bases</i>,
669 a few restrictions are imposed:
670 <ul>
671 <li>The contents of a <i>ruby base</i> or <i>ruby annotation</i> must remain contiguous.
672 To this end, the contents of each <i>ruby base</i> and <i>ruby annotation</i> are treated as if within a <i>bidi isolation</i>.
673 <li>For the purpose of ordering <i>ruby bases</i> within a <i>ruby container</i>,
674 each <i>ruby base</i> is treated as a strong character of its specified 'direction'.
675 (<i>Ruby annotations</i> are positioned with respect to their <i>bases</i>,
676 so are affected by reordering, but do not themselves participate in reordering.)
677 <li>All <i>bases</i> spanned by a single <i>annotation</i> must remain contiguous.
678 To this end, the embedding level of all bases spanned by a spanning <i>annotation</i>
679 is increased by two prior to reordering.
680 </ul>
682 <h4 id="bidi-B">Proposal B</h4>
684 <p class="note">This preserves some aspects of implicit bidi.
685 For example, annotating each half of "first-second" would not cause the word to reverse itself to "second-first" within an opposite-order paragraph.
687 <p>To avoid the interference of the <i>annotations</i> in the ordering of the base text,
688 all annotations are ignored for the purpose of resolving neutral characters in the base text;
689 and the base text is resolved exactly as if each <i>ruby base</i> were
690 just a normal <i>inline box</i> embedded in the <i>ruby container</i>'s inline formatting context.
692 <p>Furthermore, to preserve the correspondance of <i>ruby annotations</i>
693 to their respective <i>ruby bases</i>,
694 a few restrictions are imposed:
695 <ul>
696 <li>The contents of a <i>ruby base</i> must remain contiguous.
697 <li>All <i>bases</i> spanned by a single <i>annotation</i> must remain contiguous.
698 </ul>
699 <p>To this end, the text of <i>ruby base</i> boxes that are not <i>bidi-isolated</i>
700 must have its embedding level increased by two;
701 and if an <i>annotation</i> spans more than one <i>ruby base</i>,
702 the spanned text's embedding level
703 (or the embedding level assigned to the isolation, if the <i>ruby base</i> is <i>bidi-isolated</i>)
704 is further increased by two.
706 -->
708 <h3 id="line-height">
709 Ruby box and line stacking</h3>
711 <p>The 'line-height' property controls spacing between lines in CSS.
712 When inline content on line is shorter than the 'line-height',
713 half-leading is added on either side of the content,
714 as specificed in <a href="http://www.w3.org/TR/CSS21/visudet.html#line-height">CSS2.1§10.8</a>. [[!CSS21]]
716 <p>In order to ensure consistent spacing of lines,
717 documents with ruby typically ensure that the 'line-height' is large enough
718 to accommodate ruby between lines of text.
719 Therefore, ordinarily, <i>ruby annotation containers</i> and <i>ruby annotation boxes</i>
720 do not contribute to the measured height of a line's inline contents;
721 any alignment (see 'vertical-align') and line-height calculations
722 are performed using only the <i>ruby base container</i>,
723 exactly as if it were a normal inline.
725 <p>However, if the 'line-height' specified on the <i>ruby container</i>
726 is less than the distance between
727 the top of the top <i>ruby annotation container</i>
728 and the bottom of the bottom <i>ruby annotation container</i>,
729 then additional leading is added
730 on the appropriate side of the <i>ruby base container</i>
731 such that if a block consisted of three lines
732 each containing ruby identical to this,
733 none of the <i>ruby containers</i> would overlap.
735 <p class="note">Note that this does not ensure that the <i>ruby annotations</i> remain within the line box.
736 It merely ensures that <em>if all lines had equal spacing</em>
737 and equivalent amounts and positioning of <i>ruby annotations</i>,
738 there would be enough room to avoid overlap.
740 <p>Authors should ensure appropriate 'line-height' and 'padding' to accommodate ruby,
741 and be particularly careful at the beginning or end of a block
742 and when a line contains inline-level content
743 (such as images, inline blocks, or elements shifted with 'vertical-align')
744 taller than the paragraph's default font size.
746 <div class="figure">
747 <p><img src="images/rlh-a.gif"
748 alt="The content of each line sits in the middle of its line height;
749 the additional space on each side is called half-leading.
750 Ruby fits between lines if it is smaller than twice the half-leading,
751 but this means that it occupies space belonging to the half-leading of the previous line.">
752 <p class="caption">Ruby annotations will often overflow the line;
753 authors should ensure content over/under a ruby-annotated line
754 is adequately spaced to leave room for the ruby.
755 </div>
757 <p class="note">More control over how ruby affects alignment and line layout
758 will be part of the CSS Line Layout Module Level 3.
759 Note, it is currently in the process of being rewritten;
760 the current drafts should not be relied upon.
762 <h2 id="ruby-props">
763 Ruby Properties</h2>
765 <p>The following properties are introduced to control ruby positioning and alignment.
767 <h3 id="rubypos">
768 Ruby positioning: the 'ruby-position' property</h3>
770 <table class="propdef">
771 <tr>
772 <th>Name:
773 <td><dfn>ruby-position</dfn>
774 <tr>
775 <th><a href="#values">Value</a>:
776 <td>[ over | under | inter-character ] && [ right | left ]
777 <tr>
778 <th>Initial:
779 <td>over right
780 <tr>
781 <th>Applies to:
782 <td>ruby annotation containers
783 <tr>
784 <th>Inherited:
785 <td>yes
786 <tr>
787 <th>Percentages:
788 <td>N/A
789 <tr>
790 <th>Media:
791 <td>visual
792 <tr>
793 <th>Computed value:
794 <td>specified value
795 <tr>
796 <th>Animatable:
797 <td>no
798 <tr>
799 <th>Canonical order:
800 <td><abbr title="follows order of property value definition">per grammar</abbr>
801 </table>
803 <p>This property controls position of the ruby text with respect to its base.
804 Values have the following meanings:
806 <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>
807 <dl>
808 <dt><dfn title="ruby-position:over">''over''</dfn>
809 <dd>The ruby text appears <i>over</i> the base in horizontal text.
811 <div class="figure">
812 <p><img src="images/shinkansen-top.gif"
813 alt="Diagram of ruby glyph layout in horizontal mode with ruby text appearing above the base">
814 <p class="caption">Ruby over Japanese base text in horizontal layout
815 </div>
816 </dd>
818 <dt><dfn title="ruby-position:right">''right''</dfn>
819 <dd>The ruby text appears on the right side of the base in vertical text.
820 <div class="figure">
821 <p><img src="images/shinkansen-right.gif" width="33"
822 alt="Diagram of ruby glyph layout in vertical mode with ruby text apearing vertically on the right of the base">
823 <p class="caption">Ruby to the right of Japanese base text in vertical layout
824 </div>
825 </dd>
827 <dt><dfn title="ruby-position:under">''under''</dfn>
828 <dd>The ruby text appears under the base in horizontal text.
829 This is a relatively rare setting used in ideographic East Asian writing systems,
830 most easily found in educational text.
832 <div class="figure">
833 <p><img src="images/shinkansen-bottom.gif"
834 alt="Diagram of ruby glyph layout in horizontal mode with ruby text appearing below the base">
835 <p class="caption">Ruby under Japanese base text in horizontal layout
836 </div>
837 </dd>
839 <dt><dfn title="ruby-position:left">''left''</dfn>
840 <dd>The ruby text appears on the left side of the base in vertical text.
842 <div class="figure">
843 <p><img src="images/shinkansen-left.gif"
844 alt="Diagram of ruby glyph layout in vertical mode with ruby text apearing vertically on the left of the base">
845 <p class="caption">Ruby to the left of Japanese base text in vertical layout
846 </div>
847 </dd>
849 <dt><dfn title="ruby-position:inter-character">''inter-character''</dfn></dt>
850 <dd>
851 <p>The ruby text appears on the right of the base in horizontal text.
852 This value forces the 'writing-mode' of the <i>ruby annotation</i> to be vertical.
854 <p>This value is provided for the special case of traditional Chinese
855 as used especially in Taiwan:
856 ruby (made of <a href="#g-bopomofo">bopomofo</a> glyphs) in that context
857 appears vertically along the right side of the base glyph,
858 even when the layout of the base characters is horizontal:
860 <div class="figure">
861 <p><img src="images/bopomofo.gif"
862 alt="Example of Taiwanese-style ruby">
863 <p class="caption">“Bopomofo” ruby in traditional Chinese
864 (ruby text shown in blue for clarity) in horizontal layout
865 </div>
866 <p class="note">
867 Note that the user agent is responsible for ensuring the correct relative alignment and positioning of the glyphs,
868 including those corresponding to the tone marks, when displaying.
869 Tone marks are spacing characters that occur (in memory) at the end of the ruby text for each base character.
870 They are usually displayed in a separate column to the right of the bopomofo characters,
871 and the height of the tone mark depends on the number of characters in the syllable.
872 One tone mark, however, is placed above the bopomofo, not to the right of it.
873 <!-- See Taiwanese requirements doc for EPUB at http://epub-revision.googlecode.com/files/EGLS_TW_eng.ppt -->
874 </dd>
875 </dl>
877 <p>If multiple <i>ruby annotation containers</i> have the same 'ruby-position',
878 they stack along the block axis,
879 with lower levels of annotation closer to the base text.
881 <h3 id="collapsed-ruby">
882 Collapsed Ruby Annotations: the 'ruby-merge' property</h3>
884 <table class="propdef">
885 <tr>
886 <th>Name:
887 <td><dfn>ruby-merge</dfn>
888 <tr>
889 <th><a href="#values">Value</a>:
890 <td>separate | collapse | auto
891 <tr>
892 <th>Initial:
893 <td>separate
894 <tr>
895 <th>Applies to:
896 <td>ruby annotation containers
897 <tr>
898 <th>Inherited:
899 <td>yes
900 <tr>
901 <th>Percentages:
902 <td>N/A
903 <tr>
904 <th>Media:
905 <td>visual
906 <tr>
907 <th>Computed value:
908 <td>specified value
909 <tr>
910 <th>Animatable:
911 <td>no
912 <tr>
913 <th>Canonical order:
914 <td><abbr title="follows order of property value definition">per grammar</abbr>
915 </table>
917 <p>
918 This property controls how ruby annotation boxes should be rendered
919 when there are more than one in a ruby container box.
921 <p>Possible values:</p>
922 <dl>
923 <dt><dfn title="ruby-merge:separate">''separate''</dfn>
924 <dd>
925 <p>
926 Each ruby annotation box is rendered in the same column(s) as its corresponding base box(es).
927 This style is called “mono ruby” in [[JLREQ]].
929 <div class="example">
930 <p>For example, the following two markups render the same:
931 <pre><ruby>無<rt>む</ruby><ruby>常<rt>じょう</ruby></pre>
932 <p>and:
933 <pre><ruby style="ruby-merge:separate"><rb>無<rb>常<rt>む<rt>じょう</ruby></pre>
934 </div>
935 </dd>
937 <dt><dfn title="ruby-merge:collapse">''collapse''</dfn>
938 <dd>
939 <p>
940 All <i>ruby annotation boxes</i> within the same <i>ruby segment</i> on the same line are concatenated,
941 and laid out as if their contents belonged to a single <i>ruby annotation box</i>
942 spanning all their associated <i>ruby base boxes</i>.
943 This style renders similar to “group ruby” in [[JLREQ]],
944 except that <i>ruby annotations</i> are kept together with their respective <i>ruby bases</i> when breaking lines.
945 </p>
947 <div class="example">
948 <p>The following two markups render the same both characters fit on one line:
949 <pre><ruby>無常<rt>むじょう</ruby></pre>
950 <p>and:
951 <pre><ruby style="ruby-merge:collapse"><rb>無<rb>常<rt>む<rt>じょう</ruby></pre>
952 <p>However, the second one renders the same as ''ruby-position: separate''
953 when the two bases are split across lines.
954 </div>
955 </dd>
957 <dt><dfn title="ruby-merge:auto">''auto''</dfn></dt>
958 <dd>
959 <p>
960 The user agent may use any algorithm to determine how each ruby annotation box
961 is rendered to its corresponding base box,
962 with the intention that if all annotations fit over their respective bases,
963 the result is identical to “mono ruby”,
964 but if some annotations are wider than their bases
965 the space is shared in some way
966 to avoid forcing space between bases.
967 <div class="example">
968 <p>
969 One possible algorithm is described as “jukugo ruby” in [[JLREQ]].
970 <p>
971 Another, more simplified algorithm of “jukugo ruby” is
972 to render as ''separate'' if all ruby annotation boxes fit
973 within the advances of their corresponding base boxes,
974 and render as ''collapse'' otherwise.
975 </p>
976 </div>
977 </dd>
978 </dl>
980 <h3 id="ruby-align-property"><a id="rubyalign"></a>
981 Ruby Text Distribution: the 'ruby-align' property</h3>
983 <table class="propdef">
984 <tr>
985 <th>Name:
986 <td><dfn>ruby-align</dfn>
987 <tr>
988 <th><a href="#values">Value</a>:
989 <td>start | center | space-between | space-around
990 <tr>
991 <th>Initial:
992 <td>space-around
993 <tr>
994 <th>Applies to:
995 <td>ruby bases, ruby annotations, ruby base containers, ruby annotation containers
996 <tr>
997 <th>Inherited:
998 <td>yes
999 <tr>
1000 <th>Percentages:
1001 <td>N/A
1002 <tr>
1003 <th>Media:
1004 <td>visual
1005 <tr>
1006 <th>Computed value:
1007 <td>specified value (except for initial and inherit)
1008 </table>
1010 <p>This property specifies how text is distributed within the various ruby boxes
1011 when their contents do not exactly fill their respective boxes.
1012 Note that space distributed by 'ruby-align' is unrelated to, and independent of,
1013 any space distributed due to justification.
1015 <p>Values have the following meanings:
1016 <dl>
1017 <dt><dfn title="ruby-align:start">''start''</dfn></dt>
1018 <dd>The ruby content is aligned with the start edge of its box.
1019 <div class="figure">
1020 <p><img
1021 alt="Diagram of glyph layout in left aligned ruby when ruby text is shorter than base"
1022 width="145" height="91" src="images/ra-l.gif" /><img
1023 width="145" height="91"
1024 alt="Diagram of glyph layout in left aligned ruby when ruby text is longer than base"
1025 src="images/ra-l-rb.gif" />
1026 <p class="caption">''start'' ruby distribution
1027 </div>
1028 </dd>
1030 <dt><dfn title="ruby-align:center">''center''</dfn></dt>
1031 <dd>The ruby content is centered within its box.
1032 <div class="figure">
1033 <p><img width="145" height="91"
1034 alt="Diagram of glyph layout in center aligned ruby when ruby text is shorter than base"
1035 src="images/ra-c.gif" /><img width="145" height="91"
1036 alt="Diagram of glyph layout in center aligned ruby when ruby text is longer than base"
1037 src="images/ra-c-rb.gif" />
1038 <p class="caption">''center'' ruby distribution
1039 </div>
1040 </dd>
1042 <dt><dfn title="ruby-align:space-between">''space-between''</dfn></dt>
1043 <dd>
1044 <p>The ruby content expands as defined for normal text justification
1045 (as defined by 'text-justify'),
1046 except that if there are no <a href="http://www.w3.org/TR/css3-text/#expansion-opportunity"><i>expansion opportunities</i></a>
1047 the content is centered.
1048 <div class="figure">
1049 <p><img width="145" height="91"
1050 alt="Diagram of glyph layout in distribute-letter aligned ruby when ruby text is shorter than base"
1051 src="images/ra-dl.gif" /><img width="145" height="91"
1052 alt="Diagram of glyph layout in distribute-letter aligned ruby when ruby text is longer than base"
1053 src="images/ra-dl-rb.gif" />
1054 <p class="caption">''space-between'' ruby distribution
1055 </div>
1056 </dd>
1058 <dt><dfn title="ruby-align:space-around">''space-around''</dfn></dt>
1059 <dd>
1060 <p>As for ''space-between''
1061 except that there exists an extra <a href="http://www.w3.org/TR/css3-text/#expansion-opportunity"><i>expansion opportunity</i></a>
1062 whose space is distributed half before and half after the ruby content.
1063 <div class="example">
1064 <p>Since a typical implementation will by default define <i>expansion opportunities</i>
1065 between every adjacent pair of CJK <i>characters</i>
1066 and not between adjacent pairs of Latin <i>characters</i>,
1067 this should result in the behavior recommended by [[JLREQ]]:
1068 for wide-cell ruby content to be distributed...
1069 <div class="figure">
1070 <p><img width="145" height="91"
1071 alt="Diagram of glyph layout in auto aligned ruby when ruby text is shorter than base"
1072 src="images/ra-ds.gif" /><img width="145" height="91"
1073 alt="Diagram of glyph layout in auto aligned ruby when ruby text is longer than base"
1074 src="images/ra-ds-rb.gif" />
1075 <p class="caption">Wide-cell text in ''space-around'' ruby distribution is spaced apart
1076 </div>
1077 <p>... and narrow-cell glyph ruby to be centered.
1078 <div class="figure">
1079 <p><img
1080 alt="Diagram of glyph layout in auto aligned ruby when halfwidth ruby text is shorter than base"
1081 width="145" height="91"
1082 src="images/ra-c-h.gif" /><img
1083 alt="Diagram of character layout in auto aligned ruby when ruby text is longer than narrow-width base"
1084 width="145" height="91"
1085 src="images/ra-c-rb-h.gif" />
1086 <p class="caption">Narrow-width ruby text in ''space-around'' ruby distribution is centered
1087 </div>
1088 </div>
1089 </dd>
1090 </dl>
1092 <p class="issue">Add a paragraph explaining how to distribute space in situations with spanning annotations.
1093 <!--
1094 <p>For a complex ruby with spanning elements, one additional consideration is
1095 required. If the spanning element spans multiple 'rows' (other rbc or rtc
1096 elements), and the ruby alignment requires space distribution among the
1097 'spanned' elements, a ratio must be determined among the 'columns' of spanned
1098 elements. This ratio is computed by taking into consideration the widest
1099 element within each column.</p>
1100 -->
1101 <h2 id="edge-effects">
1102 Edge Effects</h2>
1104 <h3 id="ruby-overhang">
1105 Overhanging Ruby</h3>
1107 <p>
1108 When <i>ruby annotation box</i> is longer than its corresponding <i>ruby base box</i>,
1109 the <i>ruby annotation box</i> may partially overhang adjacent boxes.
1110 </p>
1111 <p>
1112 This level of the specification does not define
1113 how much the overhang may be allowed, and under what conditions.
1114 </p>
1116 <p>If the ruby text is not allowed to overhang,
1117 then the ruby behaves like a traditional inline box,
1118 i.e. only its own contents are rendered within its boundaries
1119 and adjacent elements do not cross the box boundary:
1121 <div class="figure">
1122 <p><img src="images/ro-n.gif"
1123 alt="Diagram showing the ruby boxes interacting with adjacent text">
1124 <p class="caption">Simple ruby whose text is not allowed to overhang adjacent text
1125 </div>
1127 <p>However, if <i>ruby annotation</i> content is allowed to overhang adjacent elements
1128 and it happens to be wider than its base,
1129 then the adjacent content is partially rendered within the area of the <i>ruby container box</i>,
1130 while the <i>ruby annotation</i> may partially overlap the upper blank parts of the adjacent content:
1132 <div class="figure">
1133 <p><img src="images/ro-a.gif"
1134 alt="Diagram showing the ruby boxes interacting with adjacent text">
1135 <p class="caption">Simple ruby whose text is allowed to overhang adjacent text
1136 </div>
1138 <p>The <i>ruby annotations</i> related to a <i>ruby base</i>
1139 must never overhang another <i>ruby base</i>.
1141 <p>The alignment of the contents of the base or the ruby text
1142 is not affected by overhanging behavior.
1143 The alignment is achieved the same way regardless of the overhang behavior setting
1144 and it is computed before the space available for overlap is determined.
1145 It is controlled by the 'ruby-align' property.
1147 <p class="issue">
1148 I suspect overhanging interacts with alignment in some cases;
1149 might need to look into this later.
1151 <p>This entire logic applies the same way in vertical ideographic layout,
1152 only the dimension in which it works in such a layout is vertical,
1153 instead of horizontal.
1155 <div class="example">
1156 <p>
1157 The user agent may use [[JIS4051]] recommendation of
1158 using one ruby text character length as the maximum overhang length.
1159 Detailed rules for how ruby text can overhang adjacent characters for Japanese are described by [[JLREQ]].
1160 </p>
1161 </div>
1163 <h3 id="line-edge">
1164 Line-edge Alignment</h3>
1166 <p>
1167 When a <i>ruby annotation box</i> that is longer than its <i>ruby base</i>
1168 is at the start or end edge of a line,
1169 the user agent <em>may</em> force the side of the <i>ruby annotation</i> that touches the edge of the line
1170 to align to the corresponding edge of the base.
1171 This type of alignment is described by [[JLREQ]].
1172 </p>
1173 <p>
1174 This level of the specification does not provide a mechanism to control this behavior.
1175 </p>
1176 <div class="figure">
1177 <p><img src="images/ra-le-l.gif"
1178 alt="Diagram of glyph layout in line-edge aligned ruby when ruby text is shorter than base">
1179 <img src="images/ra-le-r.gif"
1180 alt="Diagram of glyph layout in line-edge aligned ruby when ruby text is longer than base">
1181 <p class="caption">Line-edge alignment
1182 </div>
1184 <!--
1185 <h3 id="rubyover">
1186 Ruby overhanging: the 'ruby-overhang' property</h3>
1188 <table class="propdef">
1189 <tr>
1190 <th>Name:
1191 <td><dfn>ruby-overhang</dfn>
1192 <tr>
1193 <th>Value:
1194 <td>auto | start | end | none
1195 <tr>
1196 <th>Initial:
1197 <td>none
1198 <tr>
1199 <th>Applies to:
1200 <td>the parent of elements with display: ruby-text
1201 <tr>
1202 <th>Inherited:
1203 <td>yes
1204 <tr>
1205 <th>Percentages:
1206 <td>N/A
1207 <tr>
1208 <th>Media:
1209 <td>visual
1210 <tr>
1211 <th>Computed value:
1212 <td>specified value (except for initial and inherit)
1213 </table>
1215 <p>This property determines whether, and on which side, ruby text is allowed
1216 to partially overhang any adjacent text in addition to its own base, when the
1217 ruby text is wider than the ruby base. Note that ruby text is never allowed to
1218 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
1219 a maximum amount by which ruby text may overhang adjacent text. The user agent may use
1220 the [[JIS4051]] recommendation of using one ruby text character
1221 length as the maximum overhang length. Detailed rules for how ruby text can overhang adjacent characters for Japanese are described by [[JLREQ]].</p>
1223 <p>Possible values:</p>
1224 <dl>
1225 <dt><strong>auto</strong></dt>
1226 <dd>The ruby text can overhang text adjacent to the base on either side. [[JLREQ]] and [[JIS4051]] specify the categories of characters that
1227 ruby text can overhang. The user agent is free to follow those recommendations or specify its own classes of
1228 characters to overhang. This is the initial value.
1229 <div class="figure">
1230 <p><img class="example" width="177" height="91"
1231 alt="Diagram of glyph layout in overhanging ruby" src="images/ro-a.gif" /></p>
1232 <p><b>Figure 4.3.1</b>: Ruby overhanging adjacent text</p>
1233 </div>
1234 </dd>
1235 <dt><strong>start</strong></dt>
1236 <dd>The ruby text can only overhang the text that precedes it. That means, for
1237 example, that ruby cannot overhang text that is to the right of it in
1238 horizontal LTR layout, and it cannot overhang text that is below it in
1239 vertical-ideographic layout.
1240 <div class="figure">
1241 <p><img class="example" width="199" height="91"
1242 alt="Diagram of glyph layout when ruby overhangs the preceding glyphs only"
1243 src="images/ro-s.gif" /></p>
1244 <p><b>Figure 4.3.2</b>: Ruby overhanging preceding text only</p>
1245 </div>
1246 </dd>
1247 <dt><strong>end</strong></dt>
1248 <dd>The ruby text can only overhang the text that follows it. That means, for
1249 example, that ruby cannot overhang text that is to the left of it in
1250 horizontal LTR layout, and it cannot overhang text that is above it in
1251 vertical-ideographic layout.
1252 <div class="figure">
1253 <p><img class="example" width="198" height="91"
1254 alt="Diagram of glyph layout when ruby overhangs the following characters only"
1255 src="images/ro-e.gif" /></p>
1256 <p><b>Figure 4.3.3</b>: Ruby overhanging following text only</p>
1257 </div>
1258 </dd>
1259 <dt><strong>none</strong></dt>
1260 <dd>The ruby text cannot overhang any text adjacent to its base, only its
1261 own base.
1263 <div class="figure">
1264 <p><img class="example" width="220" height="91"
1265 alt="Diagram of glyph layout in non-overhanging ruby"
1266 src="images/ro-n.gif" /></p>
1267 <p><b>Figure 4.3.4</b>: Ruby not allowed to overhang adjacent text</p>
1268 </div>
1269 </dd>
1270 </dl>
1272 <h3 id="rubyspan">
1273 Ruby annotation spanning: the 'ruby-span' property</h3>
1275 <table class="propdef">
1276 <tr>
1277 <th>Name:
1278 <td><dfn>ruby-span</dfn>
1279 <tr>
1280 <th>Value:
1281 <td>attr(x) | none
1282 <tr>
1283 <th>Initial:
1284 <td>none
1285 <tr>
1286 <th>Applies to:
1287 <td>elements with display: ruby-text
1288 <tr>
1289 <th>Inherited:
1290 <td>no
1291 <tr>
1292 <th>Percentages:
1293 <td>N/A
1294 <tr>
1295 <th>Media:
1296 <td>visual
1297 <tr>
1298 <th>Computed value:
1299 <td><number>
1300 </table>
1302 <p>This property controls the spanning behavior of annotation elements. </p>
1304 <p class="note"><span class="note-label">Note:</span> A XHTML user agent may also use the <samp>rbspan</samp>
1305 attribute to get the same effect.</p>
1307 <p>Possible values:</p>
1309 <dl>
1310 <dt><strong>attr(x)</strong></dt>
1311 <dd>The value of attribute 'x' as a string value. The string value is
1312 evaluated as a <number> to determine the number of ruby base elements to be
1313 spanned by the annotation element. If the <number> is '0', it is replaced by
1314 '1'.The <number> is the computed value. </dd>
1315 <dt>none</dt>
1316 <dd>No spanning. The computed value is '1'.</dd>
1317 </dl>
1319 <p>The following example shows an XML example using the 'display' property
1320 values associated with the 'ruby structure and the 'ruby-span' property</p>
1321 <pre class="xml">myruby { display: ruby; }
1322 myrbc { display: ruby-base-container; }
1323 myrb { display: ruby-base; }
1324 myrtc.before { display: ruby-text-container; ruby-position: before}
1325 myrtc.after { display: ruby-text-container; ruby-position: after}
1326 myrt { display: ruby-text; ruby-span: attr(rbspan); }
1327 ...
1328 <myruby>
1329 <myrbc>
1330 <myrb>10</myrb>
1331 <myrb>31</myrb>
1332 <myrb>2002</myrb>
1333 </myrbc>
1334 <myrtc class="before">
1335 <myrt>Month</myrt>
1336 <myrt>Day</myrt>
1337 <myrt>Year</myrt>
1338 </myrtc>
1339 <myrtc class="after">
1340 <myrt rbspan="3">Expiration Date</myrt>
1341 </myrtc>
1342 </myruby></pre>
1343 -->
1345 <h2 id="default-stylesheet" class="no-num">
1346 Appendix A: Default Style Sheet</h2>
1348 <p><em>This section is informative.</em>
1350 <h3 id="default-ua-ruby" class="no-num">
1351 <span class="secno">A.1</span> Supporting Ruby Layout</h3>
1353 <p>The following represents a default UA style sheet
1354 for rendering HTML and XHTML ruby markup as ruby layout:
1356 <pre>
1357 <!-- -->ruby { display: ruby; }
1358 <!-- -->rb { display: ruby-base; white-space: nowrap; }
1359 <!-- -->rt { display: ruby-text; white-space: nowrap; font-size: 50%; }
1360 <!-- -->rbc { display: ruby-base-container; }
1361 <!-- -->rtc { display: ruby-text-container; }
1362 <!-- -->ruby, rb, rt, rbc, rtc { unicode-bidi: isolate; }</pre>
1364 <p>Additional rules for UAs supporting the relevant features of [[CSS3-TEXT-DECOR]] and [[CSS3-FONTS]]:
1365 <pre>rt { font-variant-east-asian: ruby; text-emphasis: none; }</pre>
1367 <p class="note">Authors should not use the above rules;
1368 a UA that supports ruby layout should provide these by default.
1370 <h3 id="default-inline" class="no-num">
1371 <span class="secno">A.2</span> Inlining Ruby Annotations</h3>
1373 <p>The following represents a sample style sheet
1374 for rendering HTML and XHTML ruby markup as inline annotations:
1376 <pre>ruby, rb, rt, rbc, rtc, rp {
1377 <!-- --> display: inline; white-space: inherit;
1378 <!-- --> font-variant-east-asian: inherit; text-emphasis: inherit; }</pre>
1380 <h3 id="default-parens" class="no-num">
1381 <span class="secno">A.3</span> Generating Parentheses</h3>
1383 <p>Unfortunately, because Selectors cannot match against text nodes,
1384 it's not possible with CSS to express rules that will automatically and correctly
1385 add parentheses to unparenthesized ruby annotations in HTML.
1386 (This is because HTML ruby allows implying the <i>ruby base</i> from raw text, without a corresponding element.)
1387 However, these rules will handle cases where either <code><rb></code>
1388 or <code><rtc></code> is used rigorously.
1390 <pre>
1391 <!-- -->/* Parens around <rtc> */
1392 <!-- -->rtc::before { content: "("; }
1393 <!-- -->rtc::after { content: ")"; }
1395 <!-- -->/* Parens before first <rt> not inside <rtc> */
1396 <!-- -->rb + rt::before,
1397 <!-- -->rtc + rt::before { content: "("; }
1399 <!-- -->/* Parens after <rt> not inside <rtc> */
1400 <!-- -->rb ~ rt:last-child::after,
1401 <!-- -->rt + rb::before { content: ")"; }
1402 <!-- -->rt + rtc::before { content: ")("; }</pre>
1404 <h2 id="glossary">
1405 Glossary</h2>
1406 <dl>
1407 <dt><a id="g-bopomofo"><strong><span
1408 lang="zh">Bopomofo</span></strong></a></dt>
1409 <dd>37 characters and 4 tone markings used as phonetics in Chinese,
1410 especially standard Mandarin.</dd>
1411 <dt><a id="g-hanja"><strong><span
1412 lang="ko">Hanja</span></strong></a></dt>
1413 <dd>Subset of the Korean writing system that utilizes ideographic
1414 characters borrowed or adapted from the Chinese writing system. Also see
1415 <a href="#g-kanji"><span lang="ja">Kanji</span></a>.</dd>
1416 <dt><a id="g-hiragana"><strong><span
1417 lang="ja">Hiragana</span></strong></a></dt>
1418 <dd>Japanese syllabic script, or character of that script. Rounded and
1419 cursive in appearance. Subset of the Japanese writing system, used together
1420 with kanji and katakana. In recent times, mostly used to write Japanese
1421 words when kanji are not available or appropriate, and word endings and
1422 particles. Also see <a
1423 href="#g-katakana"><span lang="ja">Katakana</span></a>.</dd>
1424 <dt><a id="g-ideogram"><strong>Ideograph</strong></a></dt>
1425 <dd>A character that is used to represent an idea, word, or word component,
1426 in contrast to a character from an alphabetic or syllabic script. The most
1427 well-known ideographic script is used (with some variation) in East Asia
1428 (China, Japan, Korea,...).</dd>
1429 <dt><a id="g-kana"><strong><span lang="ja">Kana</span></strong></a></dt>
1430 <dd>Collective term for hiragana and katakana.</dd>
1431 <dt><a id="g-kanji"><strong>Kanji</strong></a></dt>
1432 <dd>Japanese term for ideographs; ideographs used in Japanese. Subset of the
1433 Japanese writing system, used together with hiragana and katakana. Also see <a
1434 href="#g-hanja"><span lang="ko">Hanja</span></a>.</dd>
1435 <dt><a id="g-katakana"><strong><span
1436 lang="ja">Katakana</span></strong></a></dt>
1437 <dd>Japanese syllabic script, or character of that script. Angular in
1438 appearance. Subset of the Japanese writing system, used together with
1439 kanji and hiragana. In recent times, mainly used to write foreign words. Also see <a
1440 href="#g-hiragana"><span lang="ja">Hiragana</span></a>.</dd>
1441 </dl>
1443 <h2 id="conformance">
1444 Conformance</h2>
1446 <h3 id="conventions">
1447 Document conventions</h3>
1449 <p>Conformance requirements are expressed with a combination of
1450 descriptive assertions and RFC 2119 terminology. The key words “MUST”,
1451 “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”,
1452 “RECOMMENDED”, “MAY”, and “OPTIONAL” in the normative parts of this
1453 document are to be interpreted as described in RFC 2119.
1454 However, for readability, these words do not appear in all uppercase
1455 letters in this specification.
1457 <p>All of the text of this specification is normative except sections
1458 explicitly marked as non-normative, examples, and notes. [[!RFC2119]]</p>
1460 <p>Examples in this specification are introduced with the words “for example”
1461 or are set apart from the normative text with <code>class="example"</code>,
1462 like this:
1464 <div class="example">
1465 <p>This is an example of an informative example.</p>
1466 </div>
1468 <p>Informative notes begin with the word “Note” and are set apart from the
1469 normative text with <code>class="note"</code>, like this:
1471 <p class="note">Note, this is an informative note.</p>
1473 <h3 id="conformance-classes">
1474 Conformance classes</h3>
1476 <p>Conformance to CSS Ruby Module
1477 is defined for three conformance classes:
1478 <dl>
1479 <dt><dfn title="style sheet!!as conformance class">style sheet</dfn>
1480 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#style-sheet">CSS
1481 style sheet</a>.
1482 <dt><dfn>renderer</dfn></dt>
1483 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
1484 that interprets the semantics of a style sheet and renders
1485 documents that use them.
1486 <dt><dfn id="authoring-tool">authoring tool</dfn></dt>
1487 <dd>A <a href="http://www.w3.org/TR/CSS21/conform.html#user-agent">UA</a>
1488 that writes a style sheet.
1489 </dl>
1491 <p>A style sheet is conformant to CSS Ruby Module
1492 if all of its statements that use syntax defined in this module are valid
1493 according to the generic CSS grammar and the individual grammars of each
1494 feature defined in this module.
1496 <p>A renderer is conformant to CSS Ruby Module
1497 if, in addition to interpreting the style sheet as defined by the
1498 appropriate specifications, it supports all the features defined
1499 by CSS Ruby Module by parsing them correctly
1500 and rendering the document accordingly. However, the inability of a
1501 UA to correctly render a document due to limitations of the device
1502 does not make the UA non-conformant. (For example, a UA is not
1503 required to render color on a monochrome monitor.)
1505 <p>An authoring tool is conformant to CSS Ruby Module
1506 if it writes style sheets that are syntactically correct according to the
1507 generic CSS grammar and the individual grammars of each feature in
1508 this module, and meet all other conformance requirements of style sheets
1509 as described in this module.
1511 <h3 id="partial">
1512 Partial implementations</h3>
1514 <p>So that authors can exploit the forward-compatible parsing rules to
1515 assign fallback values, CSS renderers <strong>must</strong>
1516 treat as invalid (and <a href="http://www.w3.org/TR/CSS21/conform.html#ignore">ignore
1517 as appropriate</a>) any at-rules, properties, property values, keywords,
1518 and other syntactic constructs for which they have no usable level of
1519 support. In particular, user agents <strong>must not</strong> selectively
1520 ignore unsupported component values and honor supported values in a single
1521 multi-value property declaration: if any value is considered invalid
1522 (as unsupported values must be), CSS requires that the entire declaration
1523 be ignored.</p>
1525 <h3 id="experimental">
1526 Experimental implementations</h3>
1528 <p>To avoid clashes with future CSS features, the CSS2.1 specification
1529 reserves a <a href="http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords">prefixed
1530 syntax</a> for proprietary and experimental extensions to CSS.
1532 <p>Prior to a specification reaching the Candidate Recommendation stage
1533 in the W3C process, all implementations of a CSS feature are considered
1534 experimental. The CSS Working Group recommends that implementations
1535 use a vendor-prefixed syntax for such features, including those in
1536 W3C Working Drafts. This avoids incompatibilities with future changes
1537 in the draft.
1538 </p>
1540 <h3 id="testing">
1541 Non-experimental implementations</h3>
1543 <p>Once a specification reaches the Candidate Recommendation stage,
1544 non-experimental implementations are possible, and implementors should
1545 release an unprefixed implementation of any CR-level feature they
1546 can demonstrate to be correctly implemented according to spec.
1548 <p>To establish and maintain the interoperability of CSS across
1549 implementations, the CSS Working Group requests that non-experimental
1550 CSS renderers submit an implementation report (and, if necessary, the
1551 testcases used for that implementation report) to the W3C before
1552 releasing an unprefixed implementation of any CSS features. Testcases
1553 submitted to W3C are subject to review and correction by the CSS
1554 Working Group.
1556 <p>Further information on submitting testcases and implementation reports
1557 can be found from on the CSS Working Group's website at
1558 <a href="http://www.w3.org/Style/CSS/Test/">http://www.w3.org/Style/CSS/Test/</a>.
1559 Questions should be directed to the
1560 <a href="http://lists.w3.org/Archives/Public/public-css-testsuite">public-css-testsuite@w3.org</a>
1561 mailing list.
1563 <h2 class=no-num id="acknowledgments">
1564 Acknowledgments</h2>
1566 <p>This specification would not have been possible without the help from:</p>
1568 <p>Stephen Deach, Martin Dürst, Hideki Hiura(<span lang="ja">樋浦 秀樹</span>), Masayasu Ishikawa(<span lang="ja">石川
1569 雅康</span>), Chris
1570 Pratley, Takao Suzuki(<span lang="ja">鈴木 孝雄</span>), Frank Yung-Fong Tang, Chris Thrasher, Masafumi Yabe<span lang="ja">家辺
1571 勝文</span>), Steve Zilles.</p>
1573 <h2 class="no-num" id="changes">
1574 Changes</h2>
1576 <p>The following major changes have been made since the previous Working Draft:
1577 <dl>
1578 <dt>Remove 'ruby-span' and mentions of <code>rbspan</code>.
1579 <dd>
1580 Explicit spanning is not used in HTML ruby in favor of implicit spanning.
1581 This can't handle some pathological double-sided spanning cases,
1582 but there seems to be no requirement for these at the moment.
1583 (For implementations that support full complex XHTML Ruby,
1584 they can imply spanning from the markup the same magic way
1585 that we handle cell spanning from tables. It doesn't seem
1586 necessary to include controls this in Level 1.)
1588 <dt>Defer 'ruby-overhang' and ''ruby-align: line-end'' to Level 2.
1589 <dd>
1590 It's somewhat complicated, advanced feature.
1591 Proposal is to make this behavior UA-defined
1592 and provide some examples of acceptable options.
1594 <dt>Close issue requesting 'display: rp': use ''display: none''.
1595 <dd>
1596 The Internationalization WG added an issue requesting a display value for <rp> elements.
1597 They're supposed to be hidden when <ruby> is displayed as ruby.
1598 But this is easily accomplished already with ''display: none''.
1600 <dt>Change 'ruby-position' values to match 'text-emphasis-position'.
1601 <dd>
1602 Other than ''inter-character'', which we need to keep,
1603 it makes more sense to align ruby positions with 'text-emphasis-position',
1604 which can correctly handle various combinations of horizontal/vertical preferences.
1606 <dt>Remove unused values of 'ruby-align'.
1607 <dd>
1608 ''left'', ''right'', and ''end'' are not needed.
1610 <dt>Replace ''auto'', ''distribute-letter'', and ''distribute-space'' from 'ruby-align' with ''space-between'' and ''space-around''.
1611 <dd>
1612 The ''auto'' value relied on inspecting content to determine behavior;
1613 this can be avoided by just using ''space-around'' with standard justification rules
1614 (which allow spacing between CJK but not between Latin).
1615 Replaced ''distribute-letter'' and ''distribute-space'' with
1616 ''space-between'' and ''space-around'' for consistency with distribution keywords
1617 in [[CSS3-FLEXBOX]] and [[CSS3-ALIGN]]
1618 and to avoid any links to the definition of ''text-justify: distribute''.
1620 <dt>Added 'ruby-merge' property to control jukugo rendering.
1621 <dd>
1622 This is a stylistic effect, not a structural one;
1623 the previous model assumed that it was structural and suggested handling it by changing markup. :(
1625 <dt>Remove ''inline'' from 'ruby-position'.
1626 <dd>
1627 This is do-able via ''display: inline'' on all the ruby-related elements,
1628 see <a href="#default-inline">Appendix A</a>
1630 <dt>Added <a href="#default-style">Default Style</a> rules
1631 <dd>
1632 As requested by Internationalization WG.
1634 <dt>Wrote anonymous box generation rules
1635 <dd>
1636 And defined pairing of bases and annotations.
1637 Should now handle all the crazy proposed permutations of HTML ruby markup.
1639 <dt>Defined layout of ruby
1640 <dd>
1641 Defined in detail space distribution, white space handling, line breaking, line stacking, etc.
1642 Open issue left for bidi.
1643 </dl>
1645 <h2 class=no-num id="references">
1646 References</h2>
1648 <h3 class="no-num" id="normative-references">
1649 Normative references</h3>
1650 <!--normative-->
1652 <h3 class="no-num" id="other-references">
1653 Other references</h3>
1654 <!--informative-->
1656 <h2 class="no-num" id="index">
1657 Index</h2>
1658 <!--index-->
1660 <h2 class="no-num" id="property-index">
1661 Property index</h2>
1662 <!-- properties -->
1664 </body>
1665 </html>
1666 <!-- Keep this comment at the end of the file
1667 Local variables:
1668 mode: sgml
1669 sgml-declaration:"~/SGML/HTML4.decl"
1670 sgml-default-doctype-name:"html"
1671 sgml-minimize-attributes:t
1672 sgml-nofill-elements:("pre" "style" "br")
1673 sgml-live-element-indicator:t
1674 sgml-omittag:nil
1675 sgml-shorttag:nil
1676 sgml-namecase-general:t
1677 sgml-general-insert-case:lower
1678 sgml-always-quote-attributes:t
1679 sgml-indent-step:nil
1680 sgml-indent-data:t
1681 sgml-parent-document:nil
1682 sgml-exposed-tags:nil
1683 sgml-local-catalogs:nil
1684 sgml-local-ecat-files:nil
1685 End:
1686 -->
