[css-text] Add pre-wrap-auto

Author: frivoal

css-text/Overview.bs

@@ -20,6 +20,7 @@ At Risk: the <length> values of the 'tab-size' property
 At Risk: the 'text-justify' property
 At Risk: the percentage values of 'word-spacing'
 At Risk: the 'hanging-punctuation' property
+At Risk: the ''pre-wrap-auto'' value of the 'white-space' property
 </pre>
 
   <style type="text/css">
@@ -422,7 +423,7 @@ Languages and Typesetting</h4>
       </tr>
       <tr>
         <th><a href="#values">Value</a>:
-        <td>normal | pre | nowrap | pre-wrap | pre-line</td>
+        <td>normal | pre | nowrap | pre-wrap | pre-wrap-auto | pre-line</td>
       </tr>
       <tr>
         <th>Initial:</th>
@@ -486,11 +487,24 @@ Languages and Typesetting</h4>
     <dt><dfn>pre-wrap</dfn></dt>
     <dd>Like ''pre'', this value preserves <a>white space</a>;
       but like ''white-space/normal'', it allows wrapping.
+    <dt><dfn>pre-wrap-auto</dfn></dt>
+    <dd>Like ''pre-wrap'', this value preserves <i>white space</i> and allows wrapping.
+      However, some of the behavior is made UA dependent
+      (See <a href="#white-space-rules">The White Space Processing Rules</a>
+      for details).
+      This flexibility allows UAs to match platform conventions,
+      in particular with respect to multi-line editable text fields,
+      and when preserved <a>white space</a> at the end a line
+      would cause the line to overflow.
     <dt><dfn>pre-line</dfn></dt>
     <dd>Like ''white-space/normal'', this value collapses consecutive spaces and allows wrapping,
       but preserves <a>segment breaks</a> in the source as <a>forced line breaks</a>.
   </dl>
 
+  Issue: Suggestions of a better name for ''pre-wrap-auto'' are welcome.
+
+  Note: ''pre-wrap-auto'' is at risk.
+
   <p>The following informative table summarizes the behavior of various
     'white-space' values:</p>
 
@@ -530,6 +544,12 @@ Languages and Typesetting</h4>
         <td>Preserve</td>
         <td>Wrap</td>
       </tr>
+      <tr>
+        <th>''pre-wrap-auto''</th>
+        <td>Preserve</td>
+        <td>Preserve</td>
+        <td>Wrap</td>
+      </tr>
       <tr>
         <th>''pre-line''</th>
         <td>Preserve</td>
@@ -655,6 +675,13 @@ Languages and Typesetting</h4>
       between each of the spaces of this preserved sequence,
       as well as at the beginning
       and at the end of the sequence.</p></li>
+    <li><p>If 'white-space' is set to ''pre-wrap-auto'',
+      any sequence of spaces is preserved.
+      This is achieved by treating it as a sequence of non-breaking spaces.
+      However, unlike with ''pre-wrap'',
+      whether <a>soft wrap opportunities</a> exist in this sequence
+      is user-agent defined.
+      These UA-specific rules may be context dependent.</p></li>
     </ul>
 
     <p>Then, the entire block is rendered. Inlines are laid out, taking bidi
@@ -699,7 +726,7 @@ Languages and Typesetting</h4>
     <h4 id="line-break-transform">
       Segment Break Transformation Rules</h4>
 
-      <p>When 'white-space' is ''pre'', ''pre-wrap'', or ''pre-line'',
+      <p>When 'white-space' is ''pre'', ''pre-wrap'', ''pre-wrap-auto'', or ''pre-line'',
       <a>segment breaks</a> are not <a>collapsible</a>
       and are instead transformed into a preserved line feed (U+000A).
 
@@ -739,6 +766,9 @@ Languages and Typesetting</h4>
         from the block's starting content edge.
         The tab size is given by the 'tab-size' property.
       <li>A sequence of <a>collapsible</a> spaces at the end of a line is removed.
+      <li>If spaces or tabs at the end of a line are non-collapsible but
+         have 'white-space' set to ''pre-wrap-auto'' the UA may visually
+         collapse their character advance widths.
     </ol>
 
     <p>White space that was not removed or collapsed during the white space

css-text/Overview.html

@@ -231,6 +231,7 @@ <h2 class="no-num no-toc no-ref heading settled" id="status"><span class="conten
     <li>the <a class="property" data-link-type="propdesc" href="#propdef-text-justify">text-justify</a> property
     <li>the percentage values of <a class="property" data-link-type="propdesc" href="#propdef-word-spacing">word-spacing</a>
     <li>the <a class="property" data-link-type="propdesc" href="#propdef-hanging-punctuation">hanging-punctuation</a> property
+    <li>the <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a> value of the <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> property
    </ul></div>
 
 
@@ -872,7 +873,7 @@ <h2 class="heading settled" data-level="3" id="white-space-property"><span class
 
       <th><a href="#values">Value</a>:
 
-      <td>normal | pre | nowrap | pre-wrap | pre-line
+      <td>normal | pre | nowrap | pre-wrap | pre-wrap-auto | pre-line
 
 
 
@@ -998,6 +999,18 @@ <h2 class="heading settled" data-level="3" id="white-space-property"><span class
     <dd>Like <a class="css" data-link-type="maybe" href="#valdef-white-space-pre">pre</a>, this value preserves <a data-link-type="dfn" href="#white-space">white space</a>;
       but like <a class="css" data-link-type="maybe" href="#valdef-white-space-normal">normal</a>, it allows wrapping.
 
+    <dt><dfn class="css" data-dfn-for="white-space" data-dfn-type="value" data-export="" id="valdef-white-space-pre-wrap-auto">pre-wrap-auto<a class="self-link" href="#valdef-white-space-pre-wrap-auto"></a></dfn>
+    
+    
+    <dd>Like <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap">pre-wrap</a>, this value preserves <i>white space</i> and allows wrapping.
+      However, some of the behavior is made UA dependent
+      (See <a href="#white-space-rules">The White Space Processing Rules</a>
+      for details).
+      This flexibility allows UAs to match platform conventions,
+      in particular with respect to multi-line editable text fields,
+      and when preserved <a data-link-type="dfn" href="#white-space">white space</a> at the end a line
+      would cause the line to overflow.
+    
     <dt><dfn class="css" data-dfn-for="white-space" data-dfn-type="value" data-export="" id="valdef-white-space-pre-line">pre-line<a class="self-link" href="#valdef-white-space-pre-line"></a></dfn>
 
 
@@ -1006,6 +1019,12 @@ <h2 class="heading settled" data-level="3" id="white-space-property"><span class
 
    </dl>
 
+
+   <p class="issue" id="issue-5b12ad37"><a class="self-link" href="#issue-5b12ad37"></a> Suggestions of a better name for <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a> are welcome.</p>
+
+
+   <p class="note" role="note">Note: <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a> is at risk.</p>
+
 
    <p>The following informative table summarizes the behavior of various
     <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> values:</p>
@@ -1105,6 +1124,22 @@ <h2 class="heading settled" data-level="3" id="white-space-property"><span class
 
 
 
+     <tr>
+        
+      <th><a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a>
+      
+        
+      <td>Preserve
+      
+        
+      <td>Preserve
+      
+        
+      <td>Wrap
+      
+      
+     
+      
      <tr>
 
       <th><a class="css" data-link-type="maybe" href="#valdef-white-space-pre-line">pre-line</a>
@@ -1280,6 +1315,16 @@ <h4 class="heading settled" data-level="4.1.1" id="white-space-phase-1"><span cl
       and at the end of the sequence.</p>
 
 
+     <li>
+      <p>If <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> is set to <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a>,
+      any sequence of spaces is preserved.
+      This is achieved by treating it as a sequence of non-breaking spaces.
+      However, unlike with <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap">pre-wrap</a>,
+      whether <a data-link-type="dfn" href="#soft-wrap-opportunity">soft wrap opportunities</a> exist in this sequence
+      is user-agent defined.
+      These UA-specific rules may be context dependent.</p>
+     
+    
     </ul>
 
 
@@ -1346,7 +1391,7 @@ <h4 class="heading settled" data-level="4.1.2" id="line-break-transform"><span c
 
 
 
-    <p>When <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> is <a class="css" data-link-type="maybe" href="#valdef-white-space-pre">pre</a>, <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap">pre-wrap</a>, or <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-line">pre-line</a>,
+    <p>When <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> is <a class="css" data-link-type="maybe" href="#valdef-white-space-pre">pre</a>, <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap">pre-wrap</a>, <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a>, or <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-line">pre-line</a>,
       <a data-link-type="dfn" href="#segment-break">segment breaks</a> are not <a data-link-type="dfn" href="#collapsible-white-space">collapsible</a>
       and are instead transformed into a preserved line feed (U+000A).
 
@@ -1406,6 +1451,10 @@ <h4 class="heading settled" data-level="4.1.3" id="white-space-phase-2"><span cl
         The tab size is given by the <a class="property" data-link-type="propdesc" href="#propdef-tab-size">tab-size</a> property.
 
      <li>A sequence of <a data-link-type="dfn" href="#collapsible-white-space">collapsible</a> spaces at the end of a line is removed.
+      
+     <li>If spaces or tabs at the end of a line are non-collapsible but
+         have <a class="property" data-link-type="propdesc" href="#propdef-white-space">white-space</a> set to <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a> the UA may visually
+         collapse their character advance widths.
 
     </ol>
 
@@ -5032,6 +5081,7 @@ <h3 class="no-num heading settled" id="index-defined-here"><span class="content"
    <li>pre-line, <a href="#valdef-white-space-pre-line">3</a>
    <li>preserved, <a href="#preserved">4.1.3</a>
    <li>pre-wrap, <a href="#valdef-white-space-pre-wrap">3</a>
+   <li>pre-wrap-auto, <a href="#valdef-white-space-pre-wrap-auto">3</a>
    <li>right, <a href="#valdef-text-align-right">7.1</a>
    <li>Script property, <a href="#unicode-script">Unnumbered section</a>
    <li>segment break, <a href="#segment-break">4</a>
@@ -5189,7 +5239,7 @@ <h2 class="no-num heading settled" id="property-index"><span class="content">Pro
      <td>as specified
     <tr>
      <th scope="row"><a class="css" data-link-type="property" href="#propdef-white-space">white-space</a>
-     <td>normal | pre | nowrap | pre-wrap | pre-line
+     <td>normal | pre | nowrap | pre-wrap | pre-wrap-auto | pre-line
      <td>normal
      <td>all elements
      <td>yes
@@ -5374,6 +5424,7 @@ <h2 class="no-num heading settled" id="property-index"><span class="content">Pro
      <td>as specified</table>
   <h2 class="no-num heading settled" id="issues-index"><span class="content">Issues Index</span><a class="self-link" href="#issues-index"></a></h2>
   <div style="counter-reset:issue">
+   <div class="issue"> Suggestions of a better name for <a class="css" data-link-type="maybe" href="#valdef-white-space-pre-wrap-auto">pre-wrap-auto</a> are welcome.<a href="#issue-5b12ad37"> ↵ </a></div>
    <div class="feedback issue">Comments on how well this would work in practice would
         be very much appreciated, particularly from people who work with
         Thai and similar scripts.