[css-break] Clarify that different classes of break points do not have different priorities

Author: fantasai

css-break/Overview.html

@@ -825,7 +825,7 @@ <h3 id=possible-breaks><span class=secno>4.1. </span> Possible Break Points</h3>
    block-and-inline flow, breaks may occur at the following places:
 
   <dl>
-   <dt id=btw-blocks>Class 1
+   <dt id=btw-blocks>Class A
 
    <dd> Between sibling boxes of the following types:
     <dl>
@@ -842,20 +842,22 @@ <h3 id=possible-breaks><span class=secno>4.1. </span> Possible Break Points</h3>
       boxes, table column boxes, multi-column column boxes
     </dl>
 
-   <dt id=btw-lines>Class 2
+   <dt id=btw-lines>Class B
 
    <dd> Between line boxes inside a block container box.
 
-   <dt id=end-block>Class 3
+   <dt id=end-block>Class C
 
    <dd> Between the content edge of a block container box and the outer edges
     of its child content (margin edges of block-level children or line box
     edges for inline-level children) <em>if</em> there is a (non-zero) gap
     between them.
   </dl>
 
-  <p class=note> Other layout models may add breakpoints to the above
-   classes.
+  <p class=note> There is no inherent prioritization among these classes of
+   break points. However, individual break points may be prioritized or
+   de-prioritized by using the <a href="#breaking-controls">breaking
+   controls</a>.
 
   <p id=monolithic-breaking> The UA is not required to fragment the contents
    of <a href="#monolithic"><i>monolithic</i></a> elements, and may instead
@@ -870,6 +872,11 @@ <h3 id=possible-breaks><span class=secno>4.1. </span> Possible Break Points</h3>
    the page, and not all the content fits, the UA may break anywhere in order
    to avoid losing content off the edge of the page.
 
+  <p class=note> Other layout models may add breakpoints to the above
+   classes. For example, <a href="#CSS3-FLEXBOX"
+   rel=biblioentry>[CSS3-FLEXBOX]<!--{{CSS3-FLEXBOX}}--></a> adds certain
+   points within a flex formatting context to classes A and C.
+
   <h3 id=break-types><span class=secno>4.2. </span> Types of Breaks</h3>
 
   <p> There are different types of breaks in CSS, defined based on the type
@@ -918,7 +925,7 @@ <h3 id=forced-breaks><span class=secno>4.3. </span> Forced Breaks</h3>
 
   <p> A <dfn id=forced-break>forced break</dfn> is one explicitly indicated
    by the style sheet author. A <a href="#forced-break"><i>forced
-   break</i></a> occurs at a <a href="#btw-blocks">Class 1 break point</a>
+   break</i></a> occurs at a <a href="#btw-blocks">class A break point</a>
    if, among the ‘<a href="#break-after"><code
    class=property>break-after</code></a>’ properties specified on or
    propagated to the earlier sibling box and the ‘<a
@@ -938,9 +945,9 @@ <h3 id=forced-breaks><span class=secno>4.3. </span> Forced Breaks</h3>
    class=css>recto</code>’, and/or ‘<code class=css>verso</code>’ are
    combined, the value specified on the latest element in the flow wins.
 
-  <p class=note> A page break must also occur at <a
-   href="#btw-blocks">(1)</a> if the last line box above this margin and the
-   first one below it do not have the same value for ‘<code
+  <p class=note> A page break must also occur at a <a
+   href="#btw-blocks">class A break point</a> if the last line box above this
+   margin and the first one below it do not have the same value for ‘<code
    class=property>page</code>’. See <a href="#CSS3PAGE"
    rel=biblioentry>[CSS3PAGE]<!--{{!CSS3PAGE}}--></a>
 
@@ -961,49 +968,49 @@ <h3 id=unforced-breaks><span class=secno>4.4. </span> Unforced Breaks</h3>
    break point</a> is allowed:
 
   <dl>
-   <dt>Rule A
+   <dt>Rule 1
 
-   <dd> A fragmented flow may break at <a href="#btw-blocks">(1)</a> only if
-    all the ‘<a href="#break-after"><code
+   <dd> A fragmented flow may break at a <a href="#btw-blocks">class A break
+    point</a> only if all the ‘<a href="#break-after"><code
     class=property>break-after</code></a>’ and ‘<a
     href="#break-before"><code class=property>break-before</code></a>’
     values applicable to this break point allow it, which is when at least
     one of them forces a break or when all of them are ‘<code
     class=css>auto</code>’.
 
-   <dt>Rule B
+   <dt>Rule 2
 
    <dd> However, if all of them are ‘<code class=css>auto</code>’ and a
     common ancestor of all the elements has a ‘<a
     href="#break-inside"><code class=property>break-inside</code></a>’
     value of ‘<code class=css>avoid</code>’, then breaking here is not
     allowed.
 
-   <dt>Rule C
+   <dt>Rule 3
 
-   <dd> Breaking at <a href="#btw-lines">(2)</a> is allowed only if the
-    number of line boxes between the break and the start of the enclosing
-    block box is the value of ‘<a href="#orphans"><code
+   <dd> Breaking at a <a href="#btw-lines">class B break point</a> is allowed
+    only if the number of line boxes between the break and the start of the
+    enclosing block box is the value of ‘<a href="#orphans"><code
     class=property>orphans</code></a>’ or more, and the number of line
     boxes between the break and the end of the box is the value of ‘<a
     href="#widows"><code class=property>widows</code></a>’ or more.
 
-   <dt>Rule D
+   <dt>Rule 4
 
-   <dd> Additionally, breaking at <a href="#btw-blocks">(2)</a> or <a
-    href="#end-block">(3)</a> is allowed only if the ‘<a
+   <dd> Additionally, breaking at <a href="#btw-blocks">class B</a> or <a
+    href="#end-block">class C</a> break points is allowed only if the ‘<a
     href="#break-inside"><code class=property>break-inside</code></a>’
     property of all ancestors is ‘<code class=css>auto</code>’.
   </dl>
 
   <p> If the above doesn't provide enough break points to keep content from
-   overflowing the page boxes, then rules A, B and D are dropped in order to
+   overflowing the page boxes, then rules 1, 2 and 4 are dropped in order to
    find additional breakpoints. In this case the UA may use the ‘<code
    class=css>avoid</code>’s that are in effect at those points to weigh the
    appropriateness of the new breakpoints; however, this specification does
    not suggest a precise algorithm.
 
-  <p> If that still does not lead to sufficient break points, rule C is
+  <p> If that still does not lead to sufficient break points, rule 3 is
    dropped as well, to find still more break points.
 
   <h3 id=best-breaks><span class=secno>4.5. </span> Optimizing Unforced
@@ -1575,6 +1582,16 @@ <h3 class=no-num id=other-references>Other references</h3>
    <dd style="display: none"><!-- keeps the doc valid if the DL is empty -->
     <!---->
 
+   <dt id=CSS3-FLEXBOX>[CSS3-FLEXBOX]
+
+   <dd>Tab Atkins Jr.; Elika J. Etemad; Alex Mogilevsky. <a
+    href="http://www.w3.org/TR/2012/CR-css3-flexbox-20120918/"><cite>CSS
+    Flexible Box Layout Module.</cite></a> 18 September 2012. W3C Candidate
+    Recommendation. (Work in progress.) URL: <a
+    href="http://www.w3.org/TR/2012/CR-css3-flexbox-20120918/">http://www.w3.org/TR/2012/CR-css3-flexbox-20120918/</a>
+   </dd>
+   <!---->
+
    <dt id=CSS3-SIZING>[CSS3-SIZING]
 
    <dd>Tab Atkins Jr.; Elika J. Etemad. <a

css-break/Overview.src.html

@@ -555,7 +555,7 @@ <h3 id="possible-breaks">
     In block-and-inline flow, breaks may occur at the following places:
   </p>
   <dl>
-    <dt id="btw-blocks">Class 1</dt>
+    <dt id="btw-blocks">Class A</dt>
     <dd>
       Between sibling boxes of the following types:
       <dl>
@@ -574,11 +574,11 @@ <h3 id="possible-breaks">
           table column group boxes, table column boxes, multi-column column boxes
         </dd>
     </dl>
-    <dt id="btw-lines">Class 2</dt>
+    <dt id="btw-lines">Class B</dt>
     <dd>
       Between line boxes inside a block container box.
     </dd>
-    <dt id="end-block">Class 3</dt>
+    <dt id="end-block">Class C</dt>
     <dd>
       Between the content edge of a block container box and the outer edges of its
       child content (margin edges of block-level children or line box
@@ -588,8 +588,9 @@ <h3 id="possible-breaks">
   </dl>
 
   <p class="note">
-    Other layout models may add breakpoints to the above classes.
-  </p>
+    There is no inherent prioritization among these classes of break points.
+    However, individual break points may be prioritized or de-prioritized
+    by using the <a href="#breaking-controls">breaking controls</a>.
 
   <p id=monolithic-breaking>
     The UA is not required to fragment the contents of <i>monolithic</i> elements,
@@ -601,12 +602,19 @@ <h3 id="possible-breaks">
     if there are no <a href="#possible-breaks">possible break points</a>
     on the fragmentainer.
   </p>
+
   <p>
     When paginating, if there are no possible break points below the top
     of the page, and not all the content fits, the UA may break anywhere
     in order to avoid losing content off the edge of the page.
   </p>
 
+  <p class="note">
+    Other layout models may add breakpoints to the above classes.
+    For example, [[CSS3-FLEXBOX]] adds certain points within a flex formatting context
+    to classes A and C.
+  </p>
+
 <h3 id="break-types">
 Types of Breaks</h3>
 
@@ -655,7 +663,7 @@ <h3 id="forced-breaks">
 
   <p>
     A <dfn>forced break</dfn> is one explicitly indicated by the style sheet author.
-    A <i>forced break</i> occurs at a <a href="#btw-blocks">Class 1 break point</a> if,
+    A <i>forced break</i> occurs at a <a href="#btw-blocks">class A break point</a> if,
     among the 'break-after' properties specified on or propagated to the earlier sibling box
     and the 'break-before' properties specified on or propagated to the later sibling box
     there is at least one with a <i>forced break value</i>.
@@ -672,7 +680,7 @@ <h3 id="forced-breaks">
     the value specified on the latest element in the flow wins.
   </p>
   <p class="note">
-    A page break must also occur at <a href="#btw-blocks">(1)</a>
+    A page break must also occur at a <a href="#btw-blocks">class A break point</a>
     if the last line box above this margin and the first one below it do not have the
     same value for 'page'. See [[!CSS3PAGE]]
   </p>
@@ -696,43 +704,43 @@ <h3 id="unforced-breaks">
     at a <a href="#possible-breaks">possible break point</a> is allowed:
   </p>
   <dl>
-    <dt>Rule A</dt>
+    <dt>Rule 1</dt>
     <dd>
-      A fragmented flow may break at <a href="#btw-blocks">(1)</a> only if
+      A fragmented flow may break at a <a href="#btw-blocks">class A break point</a> only if
       all the 'break-after' and 'break-before' values applicable to this
       break point allow it, which is when at least one of them forces a
       break or when all of them are ''auto''.
     </dd>
-    <dt>Rule B</dt>
+    <dt>Rule 2</dt>
     <dd>
       However, if all of them are ''auto'' and a common ancestor of all
       the elements has a 'break-inside' value of ''avoid'', then breaking
       here is not allowed.
     </dd>
-    <dt>Rule C</dt>
+    <dt>Rule 3</dt>
     <dd>
-      Breaking at <a href="#btw-lines">(2)</a> is allowed only if the number
+      Breaking at a <a href="#btw-lines">class B break point</a> is allowed only if the number
       of line boxes between the break and the start of the enclosing block
       box is the value of 'orphans' or more, and the number of line boxes
       between the break and the end of the box is the value of 'widows' or more.
     </dd>
-    <dt>Rule D</dt>
+    <dt>Rule 4</dt>
     <dd>
-      Additionally, breaking at <a href="#btw-blocks">(2)</a> or
-      <a href="#end-block">(3)</a> is allowed only if the 'break-inside'
-      property of all ancestors is ''auto''.
+      Additionally, breaking at <a href="#btw-blocks">class B</a> or
+      <a href="#end-block">class C</a> break points
+      is allowed only if the 'break-inside' property of all ancestors is ''auto''.
     </dd>
   </dl>
   <p>
     If the above doesn't provide enough break points to keep content from
-    overflowing the page boxes, then rules A, B and D are dropped in order
+    overflowing the page boxes, then rules 1, 2 and 4 are dropped in order
     to find additional breakpoints.
     In this case the UA may use the ''avoid''s that are in effect at those
     points to weigh the appropriateness of the new breakpoints; however,
     this specification does not suggest a precise algorithm.
   </p>
   <p>
-    If that still does not lead to sufficient break points, rule C is
+    If that still does not lead to sufficient break points, rule 3 is
     dropped as well, to find still more break points.
   </p>
 

css-flexbox/Overview.src.html

@@ -2451,11 +2451,11 @@ <h2 id="pagination">
 
 		<li>
 			In a row flex container, 
-			<a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class 1 break opportunities</a> occur between sibling flex lines,
-			and <a href="http://www.w3.org/TR/css3-break/#end-block">Class 3 break opportunities</a> occur between the first/last flex line and the flex container's content edges.
+			<a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class A break opportunities</a> occur between sibling flex lines,
+			and <a href="http://www.w3.org/TR/css3-break/#end-block">Class C break opportunities</a> occur between the first/last flex line and the flex container's content edges.
 			In a column flex container, 
-			<a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class 1 break opportunities</a> occur between sibling flex items,
-			and <a href="http://www.w3.org/TR/css3-break/#end-block">Class 3 break opportunities</a> occur between the first/last flex items on a line and the flex container's content edges.
+			<a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class A break opportunities</a> occur between sibling flex items,
+			and <a href="http://www.w3.org/TR/css3-break/#end-block">Class C break opportunities</a> occur between the first/last flex items on a line and the flex container's content edges.
 			[[!CSS3-BREAK]]
 
 		<li>
@@ -2793,4 +2793,4 @@ <h2 class="no-num" id="changes">Changes</h2>
 			Clarified where zero-main-size flex items go when they're at the end of a line.
 	</ul>
 
-	<p>A <a href="http://dev.w3.org/csswg/css3-flexbox/issues-cr-2012">Disposition of Candidate Recommendation Comments</a> is available.
+	<p>A <a href="http://dev.w3.org/csswg/css3-flexbox/issues-cr-2012">Disposition of Candidate Recommendation Comments</a> is available.

css-page/Overview.src.html

@@ -2101,7 +2101,7 @@ <h3 id="using-named-pages">Using named pages: 'page'</h3>
     <td>auto
   <tr>
     <th>Applies to:
-    <td>boxes that create <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class 1</a> break points
+    <td>boxes that create <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class A</a> break points
   <tr>
     <th>Inherited:
     <td>no (but see prose)
@@ -2184,7 +2184,7 @@ <h3 id="using-named-pages">Using named pages: 'page'</h3>
     The first printed page’s type is the <i>start 'page' value</i> of the root.
 
   <li>
-    If for any two boxes meeting at a <a href="http://www.w3.org/TR/css3-break/#btw-blocks">Class 1</a> break point,
+    If for any two boxes meeting at a <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class A</a> break point,
     the <i>end 'page' value</i> of the box preceding the break
     and <i>start 'page' value</i> of the box succeeding the break
     do not match,
@@ -2194,7 +2194,7 @@ <h3 id="using-named-pages">Using named pages: 'page'</h3>
 
 <p class="note">
   Essentially, the two 'page' values compared are those from the deepest boxes
-  meeting at the class 1 break point,
+  meeting at the <a href="http://www.w3.org/TR/css3-break/#btw-blocks">class A break point</a>,
   ignoring any subtrees rooted by boxes to which the 'page' property does not apply.
 
 <p>See [[!CSS3-BREAK]] for additional details on page breaks.