- From: Elika Etemad via cvs-syncmail <cvsmail@w3.org>
- Date: Fri, 18 Nov 2011 09:14:01 +0000
- To: public-css-commits@w3.org
Update of /sources/public/csswg/css3-writing-modes
In directory hutz:/tmp/cvs-serv16817
Modified Files:
Overview.html Overview.src.html
Added Files:
mongolian-lr.jpg
Log Message:
Rewrite line-relative directions section. (Editorial.)
Index: Overview.html
===================================================================
RCS file: /sources/public/csswg/css3-writing-modes/Overview.html,v
retrieving revision 1.221
retrieving revision 1.222
diff -u -d -r1.221 -r1.222
--- Overview.html 18 Nov 2011 04:45:58 -0000 1.221
+++ Overview.html 18 Nov 2011 09:13:59 -0000 1.222
@@ -2007,37 +2007,65 @@
<h3 id=line-directions><span class=secno>6.3. </span> Line-relative
Directions</h3>
- <p>The <dfn id=line-relative-directions>line-relative directions</dfn> <a
- href="#over"><i>over</i></a>, <a href="#under"><i>under</i></a>, <a
- href="#line-left"><i>line-left</i></a>, and <a
- href="#line-right"><i>line-right</i></a> are defined relative to the <dfn
- id=line-orientation>line orientation</dfn>, which is given by a
- combination of ‘<a href="#text-orientation0"><code
+ <p>The <dfn id=line-orientation>line orientation</dfn> determines which
+ side of a line box is the logical “top” (ascender side). It is given
+ by a combination of ‘<a href="#text-orientation0"><code
class=property>text-orientation</code></a>’ and ‘<a
href="#writing-mode1"><code class=property>writing-mode</code></a>’.
- The <a href="#line-orientation"><i>line orientation</i></a> determines
- which side of the line is the “top” and thus which sides are
- <dfn id=under>under</dfn> (ascender side) and <dfn id=over>over</dfn>
- (descender side) the line. The <i>line orientation<i> also affects the
- interpretation of alignment (‘<code
- class=property>vertical-align</code>’) in the transverse dimension
- of the line. </i></i>
+ Usually the line-relative “top” corresponds to the <a
+ href="#before"><i>before</i></a> side, but this is not always the case: in
+ Mongolian typesetting (and thus by default in ‘<a
+ href="#vertical-lr"><code class=css>vertical-lr</code></a>’ writing
+ modes), the line-relative “top” corresponds to the <a
+ href="#after"><i>after</i></a> side. Hence the need for distinct
+ terminology.
- <p>In addition to its <a href="#over"><i>over</i></a> and <a
- href="#under"><i>under</i></a> sides, a line box, even a
- vertically-oriented one, also has a "left" and "right" side, which we will
- call the <a href="#line-left"><i>line-left</i></a> and <a
- href="#line-right"><i>line-right</i></a> sides of the box (as distinct
- from the physical left and physical right sides of the box). The <dfn
- id=line-left>line-left</dfn> side of a box is nominally the side from
- which <abbr title=left-to-right>LTR</abbr> text would start. The <dfn
- id=line-right>line-right</dfn> side of a box is nominally the side from
- which <abbr title=right-to-left>RTL</abbr> text would start. Depending on
- the ‘<a href="#writing-mode1"><code
- class=property>writing-mode</code></a>’ and ‘<a
- href="#text-orientation0"><code
- class=property>text-orientation</code></a>’ properties, the
- line-left side of a box correspond to the physical left, top, or bottom.
+ <div class=figure> <img alt="Mongolian mixed with English"
+ src=mongolian-lr.jpg>
+ <p class=caption>A primarily Mongolian document, such as the one above, is
+ written in vertical lines stacking left to right, but lays its Latin text
+ with the tops of the glyphs towards the right. This makes the text run in
+ the same inline direction as Mongolian (top-to-bottom) and face the same
+ direction it does in other East Asian layouts (which have vertical lines
+ stacking right to left), but the glyphs' tops are facing the bottom of
+ the line stack rather than the top, which in an English paragraph would
+ be upside-down.
+ </div>
+
+ <p>In addition to a line-relative “top” and “bottom” to map things
+ like ‘<code class=css>vertical-align: top</code>’, CSS also
+ needs to refer to a line-relative “left” and “right” in order to
+ map things like ‘<code class=css>text-align: left</code>’.
+ Thus there are four <dfn id=line-relative-directions>line-relative
+ directions</dfn>, which are defined relative to the <a
+ href="#line-orientation"><i>line orientation</i></a> as follows:
+
+ <dl>
+ <dt><dfn id=over>over</dfn>
+
+ <dd>Nominally the side that corresponds to the ascender side or “top”
+ side of a line box. (The side overlines are typically drawn on.)
+
+ <dt><dfn id=under>under</dfn>
+
+ <dd>Opposite of <a href="#over"><i>over</i></a>: the line-relative
+ “bottom” or descender side. (The side underlines are typically drawn
+ on.)
+
+ <dt><dfn id=line-left>line-left</dfn>
+
+ <dd>Nominally the side from which <abbr title=left-to-right>LTR</abbr>
+ text would start.
+
+ <dt><dfn id=line-right>line-right</dfn>
+
+ <dd>Nominally the side from which <abbr title=right-to-left>RTL</abbr>
+ text would start. (Opposite of <a
+ href="#line-left"><i>line-left</i></a>.)
+ </dl>
+
+ <p>See the <a href=logical-to-physical>table below</a> for the exact
+ mappings between physical and line-relative directions.
<div class=figure> <a href="diagrams/line-orient-up.svg"
type="image/svg+xml"> <img alt="Line orientation compass" class=landscape
@@ -2061,14 +2089,6 @@
</div>
</div>
- <p class=note>Note also that while the <a href="#over"><i>over</i></a> and
- <a href="#under"><i>under</i></a> directions often map to the same
- directions as <a href="#before">before</a> and <a href="#after">after</a>
- respectively, this mapping is reversed for some combinations of ‘<a
- href="#writing-mode1"><code class=property>writing-mode</code></a>’
- and ‘<a href="#text-orientation0"><code
- class=property>text-orientation</code></a>’.
-
<h3 id=logical-to-physical><span class=secno>6.4. </span>
Abstract-to-Physical Mappings</h3>
--- NEW FILE: mongolian-lr.jpg ---
(This appears to be a binary file; contents omitted.)
Index: Overview.src.html
===================================================================
RCS file: /sources/public/csswg/css3-writing-modes/Overview.src.html,v
retrieving revision 1.231
retrieving revision 1.232
diff -u -d -r1.231 -r1.232
--- Overview.src.html 18 Nov 2011 04:46:00 -0000 1.231
+++ Overview.src.html 18 Nov 2011 09:13:59 -0000 1.232
@@ -1441,26 +1441,49 @@
<h3 id="line-directions">
Line-relative Directions</h3>
- <p>The <dfn>line-relative directions</dfn> <i>over</i>, <i>under</i>,
- <i>line-left</i>, and <i>line-right</i> are defined relative to the
- <dfn>line orientation</dfn>, which is given by a combination of
- 'text-orientation' and 'writing-mode'. The <i>line orientation</i>
- determines which side of the line is the “top” and
- thus which sides are <dfn>under</dfn> (ascender side) and
- <dfn>over</dfn> (descender side) the line. The <i>line orientation<i>
- also affects the interpretation of alignment ('vertical-align') in the
- transverse dimension of the line.
+ <p>The <dfn>line orientation</dfn> determines which side of a line
+ box is the logical “top” (ascender side). It is given by a combination
+ of 'text-orientation' and 'writing-mode'. Usually the line-relative “top”
+ corresponds to the <i>before</i> side, but this is not always the case:
+ in Mongolian typesetting (and thus by default in ''vertical-lr'' writing
+ modes), the line-relative “top” corresponds to the <i>after</i> side.
+ Hence the need for distinct terminology.
- <p>In addition to its <i>over</i> and <i>under</i> sides, a line box, even
- a vertically-oriented one, also has a "left" and "right" side, which we
- will call the <i>line-left</i> and <i>line-right</i> sides of the box (as
- distinct from the physical left and physical right sides of the box).
- The <dfn>line-left</dfn> side of a box is nominally the side from which
- <abbr title="left-to-right">LTR</abbr> text would start. The
- <dfn>line-right</dfn> side of a box is nominally the side from which
- <abbr title="right-to-left">RTL</abbr> text would start. Depending on the
- 'writing-mode' and 'text-orientation' properties, the line-left side of
- a box correspond to the physical left, top, or bottom.
+ <div class="figure">
+ <img src="mongolian-lr.jpg" alt="Mongolian mixed with English">
+ <p class="caption">A primarily Mongolian document, such as the one above, is written in
+ vertical lines stacking left to right, but lays its Latin text with
+ the tops of the glyphs towards the right. This makes the text run in
+ the same inline direction as Mongolian (top-to-bottom) and face the
+ same direction it does in other East Asian layouts (which have vertical
+ lines stacking right to left), but the glyphs' tops are facing the
+ bottom of the line stack rather than the top, which in an English
+ paragraph would be upside-down.
+ </div>
+
+ <p>In addition to a line-relative “top” and “bottom” to map things like
+ 'vertical-align: top', CSS also needs to refer to a line-relative
+ “left” and “right” in order to map things like ''text-align: left''.
+ Thus there are four <dfn>line-relative directions</dfn>, which are
+ defined relative to the <i>line orientation</i> as follows:
+
+ <dl>
+ <dt><dfn>over</dfn>
+ <dd>Nominally the side that corresponds to the ascender side or “top”
+ side of a line box. (The side overlines are typically drawn on.)
+ <dt><dfn>under</dfn>
+ <dd>Opposite of <i>over</i>: the line-relative “bottom” or descender side.
+ (The side underlines are typically drawn on.)
+ <dt><dfn>line-left</dfn>
+ <dd>Nominally the side from which <abbr title="left-to-right">LTR</abbr>
+ text would start.
+ <dt><dfn>line-right</dfn>
+ <dd>Nominally the side from which <abbr title="right-to-left">RTL</abbr>
+ text would start. (Opposite of <i>line-left</i>.)
+ </dl>
+
+ <p>See the <a href="logical-to-physical">table below</a> for the exact
+ mappings between physical and line-relative directions.
<div class="figure">
<a href="diagrams/line-orient-up.svg" type="image/svg+xml">
@@ -1485,11 +1508,6 @@
</div>
</div>
- <p class="note">Note also that while the <i>over</i> and <i>under</i>
- directions often map to the same directions as <a href="#before">before</a>
- and <a href="#after">after</a> respectively, this mapping is reversed
- for some combinations of 'writing-mode' and 'text-orientation'.
-
<h3 id="logical-to-physical">
Abstract-to-Physical Mappings</h3>
Received on Friday, 18 November 2011 09:14:06 UTC