[css-text-3] Count trailing spaces for max-content but not min-content, use allow-end rather than force-end hanging rules. #3440 (comment)

Author: fantasai

css-text-3/Overview.bs

@@ -743,8 +743,9 @@ Text Processing</h3>
           white-space/tab-stop-threshold-006.html
         </wpt>
 
-      As preserved spaces take up space and do not hang,
-      they affect the box's intrinsic sizes ([=min-content size=] and [=max-content size=]).
+      Such preserved spaces take up space and do not hang,
+      and thus affect the box's intrinsic sizes
+      ([=min-content size=] and [=max-content size=]).
 
       <wpt>
         white-space/white-space-intrinsic-size-001.html
@@ -754,6 +755,7 @@ Text Processing</h3>
       <p class="note">Note: This value does not guarantee that there will never be any overflow due to spaces:
       for example, if the line length is so short that even a single space does not fit,
       overflow is unavoidable.</p>
+
     <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>.
@@ -777,6 +779,17 @@ Text Processing</h3>
       </wpt>
   </dl>
 
+  <p>White space that was not removed or collapsed due to white space processing
+    is called <dfn local-lt="preserved">preserved white space</dfn>.
+    In general, <a>preserved white space</a> is measured when calculating
+    the <a>intrinsic sizes</a> of text;
+    however <a>preserved white space</a>
+    that would be allowed to <a>hang</a> at the end of the line
+    (i.e. that preserved by ''pre-wrap'')
+    is excluded--
+    that is, considered to <a>hang</a>--
+    when calculating <a>min-content sizes</a> and any sizes derived thereof.
+
   <p>The following informative table summarizes the behavior of various
     'white-space' values:</p>
 
@@ -819,7 +832,7 @@ Text Processing</h3>
         <td>Preserve</td>
         <td>Preserve</td>
         <td>Wrap</td>
-	<td>Collapse or hang</td>
+	<td>Hang</td>
       </tr>
       <tr>
         <th>''break-spaces''</th>
@@ -1441,7 +1454,8 @@ Text Processing</h3>
         at the end of a line:
         <ul>
           <li>If 'white-space' is set to ''pre-wrap'',
-             the UA must <a>hang</a> this sequence.
+             the UA must <a>hang</a> this sequence
+             if it does not otherwise fit prior to justification.
              It may also visually collapse the character advance widths
              of any that would otherwise overflow.
 
@@ -1518,9 +1532,6 @@ Text Processing</h3>
       </pre>
     </div>
 
-    <p>White space that was not removed or collapsed during the white space
-      processing steps is called <dfn>preserved</dfn> white space.</p>
-
   <h3 id="tab-size-property" caniuse="css3-tabsize" oldids="tab-size">
     Tab Character Size: the 'tab-size' property</h3>