[css-text-4][css-ruby-1] Define 'text-justify: ruby' to handle default ruby space distribution w3c#771 w3c#779

Author: fantasai

css-ruby-1/Overview.bs

@@ -1748,22 +1748,24 @@ Ruby Text Distribution: the 'ruby-align' property</h3>
 -->
 
 	<div class="example">
-		Since a typical implementation will by default define [=justification opportunities=]
+		The [[#default-ua-ruby|default UA style sheet]] applies
+		''text-justify: ruby'' to [=ruby annotations=],
+		defining [=justification opportunities=]
 		between every adjacent pair of CJK [=characters=]
-		but not between adjacent pairs of Latin [=characters=],
-		the ''space-around'' and ''space-between'' values
-		will nevertheless result in narrow characters centered:
+		but not between adjacent pairs of Latin or Bopomofo [=characters=].
+		Thus, the ''space-around'' and ''space-between'' values
+		will nevertheless result in Latin or Bopomofo characters centered:
 		<div class="figure">
 			<img width="145" height="91"
 			     alt="Diagram of glyph layout in auto aligned ruby when halfwidth ruby text is shorter than base"
 			     src="images/ra-c-h.gif" >
 			<img width="145" height="91"
 			     alt="Diagram of character layout in auto aligned ruby when ruby text is longer than narrow-width base"
 			     src="images/ra-c-rb-h.gif" >
-			<p class="caption">Narrow-width ruby text in ''ruby-align/space-around'' and ''ruby-align/space-between'' ruby distribution are centered
+			<p class="caption">Non-CJK ruby text in ''ruby-align/space-around'' and ''ruby-align/space-between'' ruby distribution are centered
 		</div>
 
-		The distribution of space can be further controlled via 'text-justify'. [[CSS-TEXT-3]]
+		The distribution of space can be controlled via 'text-justify'. [[CSS-TEXT-3]]
 	</div>
 
 	Content in [=ruby bases=] and [=ruby annotations=],
@@ -2082,8 +2084,9 @@ Appendix A: Sample Style Sheets</h2>
 		ruby, rb, rt, rbc, rtc { unicode-bidi: isolate; }
 
 		rtc, rt {
-			font-variant-east-asian: ruby;  /* See [[CSS3-FONTS]] */
-			text-emphasis: none;            /* See [[CSS3-TEXT-DECOR]] */
+			font-variant-east-asian: ruby;  /* See [[CSS-FONTS-3]] */
+			text-justify: ruby;             /* See [[CSS-TEXT-4]] */
+			text-emphasis: none;            /* See [[CSS-TEXT-DECOR-3]] */
 			white-space: nowrap;
 			line-height: 1; }
 
@@ -2155,7 +2158,7 @@ Glossary</h2>
 	<dl>
 		<dt id="g-bopomofo"><dfn noexport>Bopomofo</dfn> or <dfn noexport>Zhuyin Fuhao</dfn> (Chinese: <span lang=zh-Bopo>ㄅㄆㄇㄈ</span>, <span lang=zh-Hant>注音符號</span>, or <span lang=zh-Hans>注音符号</span>)
 		<dd>
-			<p>37 characters and 4 tone markings used as phonetics in Chinese,
+			<p>Characters and tone markings developed for use as phonetics in Chinese,
 			especially standard Mandarin.
 			These are often, but not exclusively, used for ruby annotations.
 
@@ -2182,6 +2185,13 @@ Glossary</h2>
 			whether the text occurs in ruby annotations or as normal inline content.
 			Such glyph placement is not a function of CSS ruby layout.
 
+			Bopomofo [=letters=] belong to the <code>Bopomofo</code> [=Unicode script=]
+			(and are currently mapped in the U+3100–312F and U+31A0–31BF blocks);
+			the [=Bopomofo tone marks=] are
+			U+02C9 (ˉ), U+02CA (ˊ), U+02C7 (ˇ), U+02CB (ˋ), U+02EA (˪), U+02EB (˫), U+02D9 (˙).
+			Collectively these are all considered <dfn export>Bopomofo characters</dfn>
+			for the purpose of CSS.
+
 		<dt id="g-hanja">Hanja (Korean: <span lang=ko>漢字</span>)
 		<dd>
 			Subset of the Korean writing system that utilizes ideographic
@@ -2265,6 +2275,9 @@ Changes since the 2 December 2021 WD</h3>
 		<li>Made the computed-value adjustement of 'writing-mode' on [=inter-character annotations=]
 			apply to the [=ruby annotation box=] rather than the [=ruby annotation container box=].
 		<li>Added <code>zh-Hant</code> to rule applying ''font-size: 30%'' to [=ruby annotations=] in HTML.
+		<li>Added <code>text-justify: ruby</code> to the UA default style sheet.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/771">Issue 771</a>
+			 <a href="https://github.com/w3c/csswg-drafts/issues/779">Issue 779</a>)
 	</ul>
 
 <h3 id="changes-20200429">

css-text-4/Overview.bs

@@ -6928,6 +6928,16 @@ Justification Method: the 'text-justify' property</h3>
 			<wpt pathprefix="/css/css-text/text-justify/">
 			text-justify-distribute-001.html
 			</wpt>
+
+		<dt><dfn>ruby</dfn>
+		<dd>
+			Justification adjusts spacing as for ''text-justify/auto'' <em>except</em>:
+			* [=Justification opportunities=] are disabled at [=word separators=].
+			* [=Justification opportunities=] are disabled between [=Bopomofo characters=]
+
+			Note: This value is intended for use in [=ruby annotations=],
+			providing a reasonable default alignment.
+			See [[CSS-RUBY-1]].
 	</dl>
 
 	<p class="advisement">
@@ -10210,7 +10220,14 @@ Acknowledgements</h2>
 <h2 class="no-num" id="changes">
 Changes</h2>
 
-	Significant since the <a href="https://www.w3.org/TR/2019/WD-css-text-4-20191113/">2019 Working Draft</a> publication include:
+	Significant changes since the <a href="https://www.w3.org/TR/2022/WD-css-text-4-20220505/">5 May 2022 Working Draft</a> include:
+	<ul>
+		<li>Added ''text-justify/ruby'' value to 'text-justify'.
+			(<a href="https://github.com/w3c/csswg-drafts/issues/771">Issue 771</a>
+			 <a href="https://github.com/w3c/csswg-drafts/issues/779">Issue 779</a>)
+	</ul>
+
+	Significant changes since the <a href="https://www.w3.org/TR/2019/WD-css-text-4-20191113/">2019 Working Draft</a> include:
 	<ul>
 		<li>Integrating the full text of [[CSS-TEXT-3]].
 		<li>Adding percentages to 'word-spacing' and 'letter-spacing'