- From: Elika Etemad via cvs-syncmail <cvsmail@w3.org>
- Date: Tue, 07 Jun 2011 04:03:42 +0000
- To: public-css-commits@w3.org
Update of /sources/public/csswg/css3-writing-modes In directory hutz:/tmp/cvs-serv21527 Modified Files: Overview.src.html Log Message: Clean up prose relating to vertical typesetting. Index: Overview.src.html =================================================================== RCS file: /sources/public/csswg/css3-writing-modes/Overview.src.html,v retrieving revision 1.169 retrieving revision 1.170 diff -u -d -r1.169 -r1.170 --- Overview.src.html 7 Jun 2011 03:17:10 -0000 1.169 +++ Overview.src.html 7 Jun 2011 04:03:40 -0000 1.170 @@ -1127,14 +1127,10 @@ and sets the orientation of the line. Current values only have an effect in vertical writing modes. - <p id=grapheme-cluster>In this section only, the term <dfn>character</dfn> - is defined as <em>extended grapheme cluster</em> per [[!UAX29]]. It is - roughly equivalent to what a language user considers to be a character - or a basic unit of the script (which might not be a single Unicode - codepoint). - The UA may further tailor the definition as allowed by Unicode. - See <a href="#character-properties">Character Properties</a> for detailed - information on determing character properties. + <p>For readability, the term <i>character</i> is used in place of + <em>extended grapheme cluster</em> in this section. + See <a href="#character-properties">Characters and Properties</a> + for further details. <p>Values have the following meanings:</p> @@ -1217,6 +1213,21 @@ (writing-mode is vertical-rl)</p> </div> + <p>The orientation of characters belonging to the Common, Inherited, and Unknown + script categories may be UA- or font-dependent in vertical typographic + modes: + <ul> + <li><p>If the font and font system support mixed-orientation typesetting + (e.g. the OpenType font used has the <code>vrt2</code>), the + UA should rely on that feature to set ''vertical-right'' text. Similarly + if the font and font system support upright typesetting + (e.g. the OpenType font used has the <code>vert</code> feature) then the + UA should rely on that feature to set ''upright'' text. + <li><p>If the UA needs to synthesize such features, + then the settings in <a href="#vertical-typesetting-details">Appendix C</a> + are recommended. + </ul> + <div class="example"> <p>In the following example, the root element of a horizontal-only document is set to use ''sideways''. In the rest of the document, the author @@ -1230,32 +1241,6 @@ </pre> </div> -<h4 id="vertical-typesetting"> -Vertical Typesetting</h4> - - <p>In vertical typographic modes, any character belonging to a - vertical script <em>must</em> be set using its base character's - intrinsic orientation. (See <a href="#script-orientations">Appendix B</a>.) - Characters belonging to horizontal-only scripts must set sideways - (for ''vertical-right'') or set upright (for ''upright'') depending on the - 'text-orientation' property. - - <p>The orientation of characters belonging to the Common, Inherited, and Unknown - script categories may be UA- or font-dependent in vertical typographic - modes: - - <ul> - <li><p>If the font and font system support mixed-orientation typesetting, the - UA should rely on that feature to set ''vertical-right'' text. Similarly - if the font and font system support upright typesetting then the UA should - rely on that feature to set ''upright'' text. - - <li><p>If the UA needs to synthesize such features (e.g. if an OpenType font - has only the <code>vert</code> but not the <code>vrt2</code> feature), - then the settings in <a href="#vertical-typesetting-details">Appendix C</a> - are recommended. - </ul> - <h2 id="abstract-box"> Abstract Box Terminology</h2> @@ -2228,6 +2213,38 @@ { unicode-bidi: isolate; } </pre> +<h2 id="character-properties" class="no-num">Appendix Q +Characters and Properties</h2> + + <p>Unicode defines three character-level properties that are referenced + in CSS Writing Modes: + <dl> + <dt><a href="http://www.unicode.org/reports/tr11/#Definitions">East Asian width</a> + <dd>Defined in [[!UAX11]] and given as the East_Asian_Width property. + <dt><a href="http://www.unicode.org/reports/tr44/#General_Category_Values">General Category</a> + <dd>Defined in [[!UAX44]] and given as the General_Category property. + <dt><a href="http://www.unicode.org/reports/tr24/#Values">Script property</a> + <dd>Defined in [[!UAX24]] and given as the Script property. (UAs should + include any ScriptExtensions.txt assignments in this mapping.) + </dl> + + <p id=grapheme-cluster>In several sections (as noted), the term + <dfn>character</dfn> is defined as <em>extended grapheme cluster</em> + per [[!UAX29]]. It is roughly equivalent to what a language user + considers to be a character or a basic unit of the script (which + might not be a single Unicode codepoint). + The UA may further tailor this definition as allowed by Unicode. + + <p>Unicode defines properties for characters, but for 'text-orientation' and + <a href="vertical-typesetting-details">Vertical Typesetting Synthesis</a>, + it is necessary to determine the properties of a grapheme cluster. + For the purposes of CSS Writing Modes, the properties of a grapheme + cluster are given by its base character—except in one case: + grapheme clusters formed with an Enclosing Mark (Me) of the Common + script are considered to be Other Symbols (So) in the Common script. + They are assumed to have the same Unicode properties as the + Replacement Character U+FFFD. + <h2 class="no-num" id="script-orientations">Appendix B: Bi-orientational Transformations</h2> <p><em>This section is normative.</em></p> @@ -2277,6 +2294,14 @@ <p><em>This appendix is non-normative.</em></p> + <p>This section defines an algorithm for automatic typesetting of + vertical text. + + For readability, the term <i>character</i> is used in place of + <em>extended grapheme cluster</em> in this section. + See <a href="#character-properties">Characters and Properties</a> + for further details. + <p class="issue">This section needs careful review.</p> <p>When 'text-orientation' is either ''vertical-right'' or ''upright'', @@ -2296,7 +2321,7 @@ font settings if possible). <li>Set any other characters that are assigned to a script (i.e. do not belong to the Common, Inherited, or Unknown scripts) - <a href="#vertical-typesetting">as required by 'text-orientation'</a>. + as required by 'text-orientation' and <a href="#script-orientations">Appendix B</a>. </ol> <p>When 'text-orientation' is ''vertical-right'', the following settings @@ -2352,30 +2377,6 @@ If any of these are present, the font is considered to have vertical font settings available. -<h2 id="character-properties" class="no-num">Appendix Q -Characters and Properties</h2> - - <p>Unicode only defines properties for characters, but in the definition - of 'text-orientation' and in - <a href="vertical-typesetting-details">Vertical Typesetting Synthesis</a>, - it is necessary to determine the properties of a grapheme cluster. - For the purposes of CSS Writing Modes, the properties of a grapheme - cluster are given by its base character—except in one case: - grapheme clusters formed with an Enclosing Mark (Me) of the Common - script are considered to be Other Symbols (So) in the Common script - having the same Unicode properties as the Replacement Character U+FFFD. - - <p>Unicode defines three properties that are referenced here: - <dl> - <dt><a href="http://www.unicode.org/reports/tr11/#Definitions">East Asian width</a> - <dd>Defined in [[UAX11]] and given as the East_Asian_Width property. - <dt><a href="http://www.unicode.org/reports/tr44/#General_Category_Values">General Category</a> - <dd>Defined in [[UAX44]] and given as the General_Category property. - <dt><a href="http://www.unicode.org/reports/tr24/#Values">Script property</a> - <dd>Defined in [[UAX24]] and given as the Script property. (UAs should - include any ScriptExtensions.txt assignments in this mapping.) - </dl> - <h2 id="intrinsic-sizing" class="no-num">Appendix D: Intrinsic Dimensions</h2>
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