- From: Elika Etemad via cvs-syncmail <cvsmail@w3.org>
- Date: Wed, 02 Mar 2011 00:17:37 +0000
- To: public-css-commits@w3.org
Update of /sources/public/csswg/css3-writing-modes
In directory hutz:/tmp/cvs-serv4467
Modified Files:
Overview.html Overview.src.html
Log Message:
First attempt at OT metrics explanation, per <http://lists.w3.org/Archives/Public/www-archive/2011Feb/0046.html>
Index: Overview.html
===================================================================
RCS file: /sources/public/csswg/css3-writing-modes/Overview.html,v
retrieving revision 1.81
retrieving revision 1.82
diff -u -d -r1.81 -r1.82
--- Overview.html 24 Feb 2011 07:42:10 -0000 1.81
+++ Overview.html 2 Mar 2011 00:17:35 -0000 1.82
@@ -18,7 +18,7 @@
h2, .example { clear: both; }
img, object { max-width: 100%; }
</style>
- <link href="http://www.w3.org/StyleSheets/TR/W3C-WD.css" rel=stylesheet
+ <link href="http://www.w3.org/StyleSheets/TR/W3C-ED.css" rel=stylesheet
type="text/css">
<body>
@@ -28,14 +28,16 @@
<h1>CSS Writing Modes Module Level 3</h1>
- <h2 class="no-num no-toc" id=longstatus-date>W3C Working Draft 24 February
- 2011</h2>
+ <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 2 March 2011</h2>
<dl>
<dt>This version:
<dd><a
- href="http://www.w3.org/TR/2011/WD-css3-writing-modes-20110224">http://www.w3.org/TR/2011/WD-css3-writing-modes-20110224</a>
+ href="http://dev.w3.org/csswg/css3-writing-modes/">http://dev.w3.org/csswg/css3-writing-modes/</a>
+ <!--
+ <dd><a href="http://www.w3.org/TR/2011/WD-css3-writing-modes-20110302">http://www.w3.org/TR/2011/ED-css3-writing-modes-20110302</a>
+-->
<dt>Latest version:
@@ -102,42 +104,36 @@
<h2 class="no-num no-toc" id=status>Status of this document</h2>
<!--begin-status-->
- <p><em>This section describes the status of this document at the time of
- its publication. Other documents may supersede this document. A list of
- current W3C publications and the latest revision of this technical report
- can be found in the <a href="http://www.w3.org/TR/">W3C technical reports
- index at http://www.w3.org/TR/.</a></em>
-
- <p>Publication as a Working Draft does not imply endorsement by the W3C
- Membership. This is a draft document and may be updated, replaced or
- obsoleted by other documents at any time. It is inappropriate to cite this
- document as other than work in progress.
+ <p>This is a public copy of the editors' draft. It is provided for
+ discussion only and may change at any moment. Its publication here does
+ not imply endorsement of its contents by W3C. Don't cite this document
+ other than as work in progress.
<p>The (<a
href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
- mailing list <a href="mailto:www-style@w3.org">www-style@w3.org</a> (see
- <a href="http://www.w3.org/Mail/Request">instructions</a>) is preferred
- for discussion of this specification. When sending e-mail, please put the
- text “css3-writing-modes” in the subject, preferably like
- this: “[<!---->css3-writing-modes<!---->] <em>…summary of
+ mailing list <a
+ href="mailto:www-style@w3.org?Subject=%5Bcss3-writing-modes%5D%20PUT%20SUBJECT%20HERE">
+ www-style@w3.org</a> (see <a
+ href="http://www.w3.org/Mail/Request">instructions</a>) is preferred for
+ discussion of this specification. When sending e-mail, please put the text
+ “css3-writing-modes” in the subject, preferably like this:
+ “[<!---->css3-writing-modes<!---->] <em>…summary of
comment…</em>”
- <p>This document was produced by the <a
- href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
- the <a href="http://www.w3.org/Style/">Style Activity</a>).
+ <p>This document was produced by the <a href="/Style/CSS/members">CSS
+ Working Group</a> (part of the <a href="/Style/">Style Activity</a>).
<p>This document was produced by a group operating under the <a
- href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
- 2004 W3C Patent Policy</a>. W3C maintains a <a
- href="http://www.w3.org/2004/01/pp-impl/32061/status"
+ href="/Consortium/Patent-Policy-20040205/">5 February 2004 W3C Patent
+ Policy</a>. W3C maintains a <a href="/2004/01/pp-impl/32061/status"
rel=disclosure>public list of any patent disclosures</a> made in
connection with the deliverables of the group; that page also includes
instructions for disclosing a patent. An individual who has actual
knowledge of a patent which the individual believes contains <a
- href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
+ href="/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a
- href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
- 6 of the W3C Patent Policy</a>.</p>
+ href="/Consortium/Patent-Policy-20040205/#sec-Disclosure">section 6 of the
+ W3C Patent Policy</a>.</p>
<!--end-status-->
<h2 class="no-num no-toc" id=Contents>Table of Contents</h2>
@@ -181,6 +177,10 @@
<li><a href="#text-baselines"><span class=secno>4.2. </span> Text
Baselines</a>
+ <ul class=toc>
+ <li><a href="#opentype-baselines"><span class=secno>4.2.1. </span>
+ Baselines in TrueType/OpenType fonts</a>
+ </ul>
<li><a href="#replaced-baselines"><span class=secno>4.3. </span> Atomic
Inline Baselines</a>
@@ -1149,24 +1149,43 @@
<dl>
<dt>alphabetic
- <dd>The alphabetic baseline, which typically aligns with the bottom of
- uppercase Latin glyphs. In horizontal typographic mode, this is the
- dominant baseline. If the font is missing this baseline, it is assumed to
- be <span class=issue>what's a good assumption? Zero in the coord space?
- Bottom of the embox? Something else?</span>
+ <dd>The <dfn id=alphabetic-baseline>alphabetic baseline</dfn>, which
+ typically aligns with the bottom of uppercase Latin glyphs. In horizontal
+ typographic mode, this is the dominant baseline.
<dt>central
- <dd>The central baseline, which typically crosses the center of the em
- box. In vertical typographic mode, this is the dominant baseline. If the
- font is missing this baseline, it is assumed to be halfway between the
- ascender (<a href="#over"><i>over</i></a>) and descender (<a
+ <dd>The <dfn id=central-baseline>central baseline</dfn>, which typically
+ crosses the center of the em box. In vertical typographic mode, this is
+ the dominant baseline. If the font is missing this baseline, it is
+ assumed to be halfway between the ascender (<a
+ href="#over"><i>over</i></a>) and descender (<a
href="#under"><i>under</i></a>) edges of the em box.
</dl>
<p class=note>A future CSS module will deal with baselines in more detail
and allow the choice of other dominant baselines and alignment options.
+ <h4 id=opentype-baselines><span class=secno>4.2.1. </span> Baselines in
+ TrueType/OpenType fonts</h4>
+
+ <p><em>This section is non-normative.</em>
+
+ <p>The alphabetic baseline is listed as the <var>romn</var> baseline in
+ TrueType/OpenType baseline tables. If missing, it can sometimes be
+ computed from the ascender and descender metrics. If it cannot be computed
+ from other metrics, it may be assumed to correspond to the zero
+ coordinate.
+
+ <p>For the ascender and descender metrics, it is recommended to use the
+ <var>sTypoAscender</var> and <var>sTypoDescender</var> metrics from the
+ font's OS/2 table. These should match the <var>idtp</var> and
+ <var>ideo</var> baselines (respectively), which, if present, may be used
+ instead. In the absence of these metrics, the <var>Ascent</var> and
+ <var>Descent</var> metrics from the HHEA table should be used. The Win
+ metrics can be used as a fallback; however these are intended as clipping
+ bounds and are not always appropriate for use as em box measurements.
+
<h3 id=replaced-baselines><span class=secno>4.3. </span> Atomic Inline
Baselines</h3>
@@ -2503,9 +2522,10 @@
<dt id=UAX29>[UAX29]
<dd>Mark Davis. <a
- href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html"><cite>Text
- Boundaries.</cite></a> 25 March 2005. Unicode Standard Annex #29. URL: <a
- href="http://www.unicode.org/unicode/reports/tr29/tr29-9.html">http://www.unicode.org/unicode/reports/tr29/tr29-9.html</a>
+ href="http://www.unicode.org/reports/tr29/tr29-17.html"><cite>Unicode
+ Text Segmentation.</cite></a> 8 October 2010. Unicode Standard Annex #29.
+ URL: <a
+ href="http://www.unicode.org/reports/tr29/tr29-17.html">http://www.unicode.org/reports/tr29/tr29-17.html</a>
</dd>
<!---->
</dl>
Index: Overview.src.html
===================================================================
RCS file: /sources/public/csswg/css3-writing-modes/Overview.src.html,v
retrieving revision 1.85
retrieving revision 1.86
diff -u -d -r1.85 -r1.86
--- Overview.src.html 24 Feb 2011 07:42:10 -0000 1.85
+++ Overview.src.html 2 Mar 2011 00:17:35 -0000 1.86
@@ -30,7 +30,10 @@
<h2 class="no-num no-toc">[LONGSTATUS] [DATE]</h2>
<dl>
<dt>This version:</dt>
+ <dd><a href="http://dev.w3.org/csswg/css3-writing-modes/">http://dev.w3.org/csswg/css3-writing-modes/</a>
+<!--
<dd><a href="http://www.w3.org/TR/[YEAR]/WD-[SHORTNAME]-[CDATE]">[VERSION]</a>
+-->
<dt>Latest version:</dt>
<dd><a
href="http://www.w3.org/TR/css3-writing-modes/">http://www.w3.org/TR/css3-writing-modes/</a></dd>
@@ -811,24 +814,44 @@
<dl>
<dt>alphabetic</dt>
- <dd>The alphabetic baseline, which typically aligns with the bottom
- of uppercase Latin glyphs. In horizontal typographic mode,
- this is the dominant baseline. If the font is missing this
- baseline, it is assumed to be <span class="issue">what's a
- good assumption? Zero in the coord space? Bottom of the embox?
- Something else?</span></dd>
+ <dd>The <dfn>alphabetic baseline</dfn>, which typically aligns with the
+ bottom of uppercase Latin glyphs. In horizontal typographic mode,
+ this is the dominant baseline.
+
+ </dd>
<dt>central</dt>
- <dd>The central baseline, which typically crosses the center
+ <dd>The <dfn>central baseline</dfn>, which typically crosses the center
of the em box. In vertical typographic mode, this is the
dominant baseline. If the font is missing this baseline,
it is assumed to be halfway between the ascender (<i>over</i>)
- and descender (<i>under</i>) edges of the em box.</dd>
+ and descender (<i>under</i>) edges of the em box.
+ </dd>
</dl>
<p class="note">A future CSS module will deal with baselines in more
detail and allow the choice of other dominant baselines and alignment
options.</p>
+<h4 id="opentype-baselines">
+Baselines in TrueType/OpenType fonts</h4>
+
+ <p><em>This section is non-normative.</em></p>
+
+ <p>The alphabetic baseline is listed as the <var>romn</var>
+ baseline in TrueType/OpenType baseline tables. If missing, it can
+ sometimes be computed from the ascender and descender metrics. If it
+ cannot be computed from other metrics, it may be assumed to correspond
+ to the zero coordinate.</p>
+
+ <p>For the ascender and descender metrics, it is recommended to use the
+ <var>sTypoAscender</var> and <var>sTypoDescender</var> metrics from the
+ font's OS/2 table. These should match the <var>idtp</var> and <var>ideo</var>
+ baselines (respectively), which, if present, may be used instead. In the
+ absence of these metrics, the <var>Ascent</var> and <var>Descent</var>
+ metrics from the HHEA table should be used. The Win metrics can be
+ used as a fallback; however these are intended as clipping bounds and
+ are not always appropriate for use as em box measurements.</em>
+
<h3 id="replaced-baselines">
Atomic Inline Baselines</h3>
Received on Wednesday, 2 March 2011 00:17:39 UTC