Merge pull request w3c#89 from ChumpChief/master

[css-snappoints] A few minor updates plus clarification of post-content snapping

Author: ChumpChief

css-snappoints/Overview.bs

@@ -64,7 +64,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
         sizes vary.  Using mandatory element-based snap
         positions, scrolling will always complete with an image centered in the <a>scroll container's</a> visual viewport.
 
-        <pre>
+        <pre class="lang-css">
             img {
                 /* Specifies that the center of each photo 
                    should align with the center of the scroll 
@@ -83,7 +83,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
             }
         </pre>
 
-        <pre>
+        <pre class="lang-html">
             &lt;div class="photoGallery">
                 &lt;img src="img1.jpg">
                 &lt;img src="img2.jpg">
@@ -110,7 +110,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
         to snap one page at a time).  However, if a scrolling operation would finish near a snap position, then the scroll will be adjusted to
         align the page as specified.
 
-        <pre>
+        <pre class="lang-css">
             .page {
                 /* Defines the top of each page as the
                    edge that should be used for snapping */
@@ -129,7 +129,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
             }
         </pre>
 
-        <pre>
+        <pre class="lang-html">
             &lt;div class="docScroller">
                 &lt;div class="page">Page 1&lt;/div>
                 &lt;div class="page">Page 2&lt;/div>
@@ -194,7 +194,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
 
 <h2 id="scroll-snap-type">Scroll Snap Types: the 'scroll-snap-type' property</h2>
 
-    The ''scroll-snap-type'' property defines how strictly a <a>scroll container's</a> visual viewport should rest on <a>snap positions</a>.  It intentionally does not specify nor mandate any precise animations or physics used to enforce those snap position; this is left up to the user agent.
+    The ''scroll-snap-type'' property defines how strictly a <a>scroll container's</a> visual viewport should rest on <a>snap positions</a>.  It intentionally does not specify nor mandate any precise animations or physics used to enforce those snap positions; this is left up to the user agent.
 
     <p class="issue">
         <a href="https://lists.w3.org/Archives/Public/www-style/2015Nov/0328.html">Open issue</a> on whether to enhance the scroll-snap-type property for specifying the axis or adding a second property.  We have <a href="https://lists.w3.org/Archives/Public/www-style/2015Dec/0048.html">resolved</a> that this functionality be added once the issue is resolved.
@@ -208,7 +208,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
     Inherited: no
     Percentages: n/a
     Media: interactive
-    Computed value: specified value
+    Computed value: as specified
     Animatable: no
     </pre>
 
@@ -219,11 +219,15 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
 
         <dt><dfn>mandatory</dfn>
         <dd>
-            The visual viewport of this <a>scroll container</a> is guaranteed to rest on a snap position when there are no active scrolling operations.  That is, it must come to rest on a snap position at the termination of a scroll, if a valid, reachable snap position exists.  If no valid, reachable snap position exists then no snapping occurs.  If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset must be modified to maintain this guarantee.
+            The visual viewport of this <a>scroll container</a> is guaranteed to rest on a snap position when there are no active scrolling operations.  That is, it must come to rest on a snap position at the termination of a scroll, if a valid, reachable snap position exists.  If no valid, reachable snap position exists then no snapping occurs.
+
+            If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset must be modified to maintain alignment of the visual viewport with a snap position.  If the visual viewport was already aligned with a snap position prior to the content change and that snap position still exists (e.g. its associated element was not deleted), that same snap position must be satisfied after the content change.
 
         <dt><dfn>proximity</dfn>
         <dd>
-            The visual viewport of this <a>scroll container</a> may come to rest on a snap position at the termination of a scroll at the discretion of the UA given the parameters of the scroll.  If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset may be modified to maintain this guarantee.
+            The visual viewport of this <a>scroll container</a> may come to rest on a snap position at the termination of a scroll at the discretion of the UA given the parameters of the scroll.
+
+            If the content changes such that the visual viewport would no longer rest on a snap position (e.g. content is added, moved, deleted, resized), the scroll offset may be modified to maintain alignment of the visual viewport with a snap position.  If the visual viewport was already aligned with a snap position prior to the content change and that snap position still exists (e.g. its associated element was not deleted) and if the user agent elects to modify the scroll offset to maintain snap position alignment, that same snap position should be satisfied after the content change.
     </dl>
 
 <h2 id="scroll-snap-padding">Scroll Snap Padding: the 'scroll-snap-padding' property</h2>
@@ -238,7 +242,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
     Inherited: no
     Percentages: relative to the scroll container's visual viewport
     Media: interactive
-    Computed value: specified value, with lengths made absolute
+    Computed value: as specified, with lengths made absolute
     Animatable: yes
     </pre>
 
@@ -262,7 +266,7 @@ Ignored Terms: scroll-snap-positions-*, containing block chain
     Inherited: no
     Percentages: relative to the specified element box
     Media: interactive
-    Computed value: specified value, with lengths made absolute
+    Computed value: as specified, with lengths made absolute
     Animatable: yes
     </pre>