Bidi fixes, r=aharon

Author: fantasai

css3-writing-modes/Overview.html

@@ -32,15 +32,15 @@
 
    <h1>CSS Writing Modes Module Level 3</h1>
 
-   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 31 July 2012</h2>
+   <h2 class="no-num no-toc" id=longstatus-date>Editor's Draft 2 August 2012</h2>
 
    <dl>
     <dt>This version:
 
     <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/2012/WD-css3-writing-modes-20120731/">http://www.w3.org/TR/2012/ED-css3-writing-modes-20120731/</a>
+    <dd><a href="http://www.w3.org/TR/2012/WD-css3-writing-modes-20120802/">http://www.w3.org/TR/2012/ED-css3-writing-modes-20120802/</a>
 -->
 
 
@@ -545,9 +545,9 @@ <h2 id=text-direction><span class=secno>2. </span><a name=bidi> Inline
   <p>Two CSS properties, ‘<a href="#direction0"><code
    class=property>direction</code></a>’ and ‘<a
    href="#unicode-bidi0"><code class=property>unicode-bidi</code></a>’,
-   provide explicit embedding and override controls in the CSS layer. Because
-   the base directionality of a text depends on the structure and semantics
-   of the document, the ‘<a href="#direction0"><code
+   provide explicit embedding, isolation, and override controls in the CSS
+   layer. Because the base directionality of a text depends on the structure
+   and semantics of the document, the ‘<a href="#direction0"><code
    class=property>direction</code></a>’ and ‘<a
    href="#unicode-bidi0"><code class=property>unicode-bidi</code></a>’
    properties should in most cases be used only to map bidi information in
@@ -558,23 +558,18 @@ <h2 id=text-direction><span class=secno>2. </span><a name=bidi> Inline
 
   <p>In general, the paragraph embedding level is set according to the ‘<a
    href="#direction0"><code class=property>direction</code></a>’ property
-   of the element <i>immediately containing</i> the paragraph rather than by
-   the heuristic given in steps P2 and P3 of the Unicode algorithm. <a
-   href="#UAX9" rel=biblioentry>[UAX9]<!--{{!UAX9}}--></a> When the computed
-   ‘<a href="#unicode-bidi0"><code
-   class=property>unicode-bidi</code></a>’ of the element <i>immediately
-   containing</i> the paragraph is ‘<a href="#plaintext"><code
-   class=css>plaintext</code></a>’, however, the Unicode heuristics are
-   used instead. An element <dfn id=bidi-contains>immediately contains</dfn>
-   a bidi paragraph if the element itself, but none of its descendants, both
-   contains the entire bidi paragraph and is a block container or <a
-   href="#bidi-isolate"><i>bidi-isolating</i></a> inline.
+   of the paragraph's containing block rather than by the heuristic given in
+   steps P2 and P3 of the Unicode algorithm. <a href="#UAX9"
+   rel=biblioentry>[UAX9]<!--{{!UAX9}}--></a> When the computed ‘<a
+   href="#unicode-bidi0"><code class=property>unicode-bidi</code></a>’ of
+   the paragraph's containing block is ‘<a href="#plaintext"><code
+   class=css>plaintext</code></a>’, however, the Unicode heuristics (rules
+   P2 and P3) are used instead.
 
   <p>The HTML specifications (<a href="#HTML401"
    rel=biblioentry>[HTML401]<!--{{HTML401}}--></a>, section 8.2, and <a
    href="#HTML5" rel=biblioentry>[HTML5]<!--{{HTML5}}--></a>, section 10.3.5)
-   define bidirectionality behavior for HTML elements. The HTML 4
-   specification also contains more information on bidirectionality issues.
+   define bidirectionality behavior for HTML elements.
 
   <p class=note>Because HTML UAs can turn off CSS styling, we advise HTML
    authors to use the HTML ‘<code class=property>dir</code>’ attribute
@@ -629,11 +624,12 @@ <h3 id=direction><span class=secno>2.1. </span> Specifying Directionality:
   </table>
 
   <p>This property specifies the inline base direction or directionality of
-   any bidi paragraph, embedding, or override established by the element.
-   (See ‘<a href="#unicode-bidi0"><code
-   class=property>unicode-bidi</code></a>’) In addition, it informs the
-   ordering of <a href="http://www.w3.org/TR/CSS21/tables.html">table</a>
-   column layout, the direction of horizontal <a
+   any bidi paragraph, embedding, isolate, or override established by the
+   element. (See ‘<a href="#unicode-bidi0"><code
+   class=property>unicode-bidi</code></a>’.) <!-- except plaintext --> In
+   addition, it informs the ordering of <a
+   href="http://www.w3.org/TR/CSS21/tables.html">table</a> column layout, the
+   direction of horizontal <a
    href="http://www.w3.org/TR/CSS21/visufx.html#overflow">overflow</a>, and
    the default alignment of text within a line, and other layout effects that
    depend on the element's inline base direction.
@@ -729,9 +725,9 @@ <h3 id=unicode-bidi><span class=secno>2.2. </span> Embeddings and
   <p>Normally (i.e. when ‘<a href="#unicode-bidi0"><code
    class=property>unicode-bidi</code></a>’ is ‘<a href="#normal"><code
    class=css>normal</code></a>’) an inline element is transparent to the
-   unicode bidi algorithm; content is ordered as if the element boundaries
-   were not there. The ‘<a href="#unicode-bidi0"><code
-   class=property>unicode-bidi</code></a>’ property allows inline elements
+   unicode bidi algorithm; content is ordered as if the element's boundaries
+   were not there. Other values of the ‘<a href="#unicode-bidi0"><code
+   class=property>unicode-bidi</code></a>’ property cause inline elements
    to create scopes within the algorithm, and to override the intrinsic
    directionality of text.
 
@@ -808,51 +804,74 @@ <h3 id=unicode-bidi><span class=secno>2.2. </span> Embeddings and
 
    <dt><dfn id=embed>embed</dfn>
 
-   <dd>If the element is inline, this value opens an additional level of
-    embedding with respect to the bidirectional algorithm. The direction of
-    this embedding level is given by the ‘<a href="#direction0"><code
-    class=property>direction</code></a>’ property. Inside the element,
-    reordering is done implicitly. This corresponds to adding a LRE (U+202A),
-    for ‘<code class=css>direction: ltr</code>’, or RLE (U+202B), for
-    ‘<code class=css>direction: rtl</code>’, at the start of the element
-    and a PDF (U+202C) at the end of the element. <span class=note>This value
-    has no effect on elements that are not inline.</span>
+   <dd>If the element is inline, this value creates a <dfn
+    id=directional-embedding>directional embedding</dfn> by opening an
+    additional level of embedding with respect to the bidirectional
+    algorithm. The direction of this embedding level is given by the ‘<a
+    href="#direction0"><code class=property>direction</code></a>’ property.
+    Inside the element, reordering is done implicitly. This corresponds to
+    adding a LRE (U+202A), for ‘<code class=css>direction: ltr</code>’,
+    or RLE (U+202B), for ‘<code class=css>direction: rtl</code>’, at the
+    start of the element and a PDF (U+202C) at the end of the element. <span
+    class=note>This value has no effect on elements that are not
+    inline.</span>
 
    <dt><dfn id=isolate>isolate</dfn>
 
    <dd>On an inline element, this <dfn id=bidi-isolate
     title="bidi-isolate|bidi isolation|isolation">bidi-isolates</dfn> its
-    contents: for the purpose of bidi resolution in its containing bidi
-    paragraph (if any), the element is treated as if it were an Object
-    Replacement Character (U+FFFC). (If the element is broken across multiple
-    lines, then each box of the element is treated as an Object Replacement
-    Character.) Within the element, its contents are considered, for the
-    purposes of bidi resolution, to be inside a separate, independent
-    document whose <a href="#paragraph"><i>bidi paragraphs</i></a> are
-    assigned the base directionality specified by the element's ‘<a
-    href="#direction0"><code class=property>direction</code></a>’ property.
+    contents. This is similar to a directional embedding (and increases the
+    embedding level accordingly) except that each sequence of inline-level
+    boxes uninterrupted by any block boundary or <a
+    href="#forced-paragraph-break"><i>forced paragraph break</i></a> is
+    treated as an <dfn id=isolated-sequence->isolated sequence<dfn>:
+    </dfn></dfn>
+    <ul>
+     <li>the content within the sequence is ordered as if inside an
+      independent paragraph with the base directionality specified by the
+      element's ‘<a href="#direction0"><code
+      class=property>direction</code></a>’ property.
+
+     <li>for the purpose of bidi resolution in its containing bidi paragraph,
+      the sequence is treated as if it were a single Object Replacement
+      Character (U+FFFC).
+    </ul>
+    In effect, neither is the content inside the element bidi-affected by the
+    content surrounding the element, nor is the content surrounding the
+    element bidi-affected by the content or specified directionality of the
+    element. However, <a href="#forced-paragraph-break"><i>forced paragraph
+    breaks</i></a> within the element still create a corresponding break in
+    the containing paragraph.
+    <p class=note>In Unicode 7.0 and beyond, this will correspond to adding
+     an LRI (U+2066), for ‘<code class=css>direction: ltr</code>’, or RLI
+     (U+2067), for ‘<code class=css>direction: rtl</code>’, at the start
+     of the element, and a PDI (U+2069) at the end of the element.
+
+    <p class=note>This value has no effect on elements that are not inline.
 
    <dt><dfn id=bidi-override>bidi-override</dfn>
 
-   <dd>For inline elements this creates an <dfn id=override>override</dfn>.
-    (For block-container elements this creates an <a
-    href="#override"><i>override</i></a> for inline-level descendants not
-    within another block container element.) This means that inside the
-    element, reordering is strictly in sequence according to the ‘<a
-    href="#direction0"><code class=property>direction</code></a>’ property;
-    the implicit part of the bidirectional algorithm is ignored. This
-    corresponds to adding a LRO (U+202D), for ‘<code class=css>direction:
-    ltr</code>’, or RLO (U+202E), for ‘<code class=css>direction:
-    rtl</code>’, at the start of the element and a PDF (U+202C) at the end
-    of the element.
+   <dd>This value puts the element's immediate content in a <dfn
+    id=directional-override>directional override</dfn>. For an inline, this
+    means that the element acts like a <a
+    href="#directional-embedding"><i>directional embedding</i></a> in the
+    bidirectional algorithm, except that reordering within it is strictly in
+    sequence according to the ‘<a href="#direction0"><code
+    class=property>direction</code></a>’ property; the implicit part of the
+    bidirectional algorithm is ignored. This corresponds to adding a LRO
+    (U+202D), for ‘<code class=css>direction: ltr</code>’, or RLO
+    (U+202E), for ‘<code class=css>direction: rtl</code>’, at the start
+    of the element and a PDF (U+202C) at the end of the element. If the
+    element is a block container, the override is applied to an anonymous
+    inline element that surrounds all of its content.
 
    <dt><dfn id=isolate-override>isolate-override<dfn></dfn></dfn>
 
    <dd>This combines the <a href="#bidi-isolate"><i>isolation</i></a>
     behavior of ‘<a href="#isolate"><code class=css>isolate</code></a>’
-    with the <a href="#override"><i>override</i></a> behavior of ‘<a
-    href="#bidi-override"><code class=css>bidi-override</code></a>’: to
-    surrounding content, it is equivalent to ‘<a href="#isolate"><code
+    with the <i>override</i> behavior of ‘<a href="#bidi-override"><code
+    class=css>bidi-override</code></a>’: to surrounding content, it is
+    equivalent to ‘<a href="#isolate"><code
     class=css>isolate</code></a>’, but within the element content is
     ordered as if ‘<a href="#bidi-override"><code
     class=css>bidi-override</code></a>’ were specified.
@@ -863,11 +882,16 @@ <h3 id=unicode-bidi><span class=secno>2.2. </span> Embeddings and
     <p>This value behaves as ‘<a href="#isolate"><code
      class=css>isolate</code></a>’ except that for the purposes of the
      Unicode bidirectional algorithm, the base directionality of each of the
-     element's <a href="#paragraph"><i>bidi paragraphs</i></a> is determined
-     by following the heuristic in rules P2 and P3 of the Unicode
-     bidirectional algorithm (rather than by using the ‘<a
-     href="#direction0"><code class=property>direction</code></a>’ property
-     of the element).
+     element's <a href="#paragraph"><i>bidi paragraphs</i></a> (if a block
+     container) or <a href="#isolated-sequence-"><i>isolated
+     sequences</i></a> (if an inline) is determined by following the
+     heuristic in rules P2 and P3 of the Unicode bidirectional algorithm
+     (rather than by using the ‘<a href="#direction0"><code
+     class=property>direction</code></a>’ property of the element).
+
+    <p class=note>In Unicode 7.0 and beyond, for inline elements this will
+     correspond to adding an FSI (U+2068) at the start of the element, and a
+     PDI (U+2069) at the end of the element.
   </dl>
 
   <p class=note>Because the ‘<a href="#unicode-bidi0"><code
@@ -906,22 +930,38 @@ <h3 id=unicode-bidi><span class=secno>2.2. </span> Embeddings and
   <p>If an inline element is broken around a <a href="#paragraph"><i>bidi
    paragraph</i></a> boundary (e.g. if split by a block or <a
    href="#forced-paragraph-break"><i>forced paragraph break</i></a>), then
-   the bidi control codes corresponding to the end of the element are added
-   before the interruption and the codes corresponding to the start of the
-   element are added after it. (In other words, any embedding levels or
-   overrides started by the element are closed at the paragraph break and
-   reopened on the other side of it.)
-
-  <p>Because the Unicode algorithm has a limit of 61 levels of embedding,
-   care should be taken not to use ‘<a href="#unicode-bidi0"><code
-   class=property>unicode-bidi</code></a>’ with a value other than ‘<a
-   href="#normal"><code class=property>normal</code></a>’ unless
-   appropriate. In particular, a value of ‘<code
-   class=css>inherit</code>’ should be used with extreme caution. However,
-   for elements that are, in general, intended to be displayed as blocks, a
-   setting of ‘<code class=css>unicode-bidi: isolate</code>’ is preferred
-   to keep the element together in case the ‘<code
-   class=property>display</code>’ is changed to ‘<code
+   the bidi control codes assigned to the end of the element are added before
+   the interruption and the codes assigned to the start of the element are
+   added after it. (In other words, any embedding levels or overrides started
+   by the element are closed at the paragraph break and reopened on the other
+   side of it.)
+
+  <div class=example>
+   <p>For example, where &lt;BR/&gt; is a <a
+    href="#forced-paragraph-break"><i>forced paragraph break</i></a> the bidi
+    ordering is identical between
+
+   <pre>&lt;para>...&lt;i1>&lt;i2>...&lt;BR/>...&lt;/i2>&lt;i1>...&lt;/para></pre>
+
+   <p>and
+
+   <pre>&lt;para>...&lt;i1>&lt;i2>...&lt;/i2>&lt;i1>&lt;BR/>&lt;i1>&lt;i2>...&lt;/i2>&lt;i1>...&lt;/para></pre>
+
+   <p>for all values of ‘<a href="#unicode-bidi0"><code
+    class=property>unicode-bidi</code></a>’ on inline elements &lt;i1&gt;
+    and &lt;i2&gt;.
+  </div>
+
+  <p class=note> Because the Unicode algorithm has a limit of 61 levels of
+   embedding, care should be taken not to use ‘<a
+   href="#unicode-bidi0"><code class=property>unicode-bidi</code></a>’ with
+   a value other than ‘<a href="#normal"><code
+   class=property>normal</code></a>’ unless appropriate. In particular, a
+   value of ‘<code class=css>inherit</code>’ should be used with extreme
+   caution. However, for elements that are, in general, intended to be
+   displayed as blocks, a setting of ‘<code class=css>unicode-bidi:
+   isolate</code>’ is preferred to keep the element together in case the
+   ‘<code class=property>display</code>’ is changed to ‘<code
    class=css>inline</code>’ (see example below).
 
   <h3 id=bidi-example><span class=secno>2.3. </span> Example of Bidirectional
@@ -4048,8 +4088,8 @@ <h2 class=no-num id=intrinsic-sizing>Appendix D: Intrinsic Dimensions</h2>
 
   <p>For replaced elements, the <a href="#min-content"><i>min-content</i></a>
    and <a href="#max-content"><i>max-content</i></a> sizes are equivalent and
-   correspond used size of the replaced element according to the ‘<code
-   class=css>auto</code>’ width and height calculations.
+   correspond to the used size of the replaced element according to the
+   ‘<code class=css>auto</code>’ width and height calculations.
 
   <h3 class=no-num id=multicol-intrinsic> Intrinsic Sizes in Multi-column
    Layout</h3>