[css-overflow-3] Editorial cleanup over the spec. Some significant rewriting, but should have no normative implications.

Author: fantasai

css-overflow-3/Overview.bs

@@ -58,6 +58,7 @@ Introduction</h2>
 	is that the content not be shown.
 
 	This specification introduces the long-standing de-facto 'overflow-x' and 'overflow-y' properties,
+	adds a ''overflow/clip'' value,
 	and defines overflow handling more fully.
 
 	[Something something 'max-lines'.]
@@ -73,7 +74,7 @@ Introduction</h2>
 -->
 
 <h2 id="overflow-concepts">
-Types of overflow</h2>
+Types of Overflow</h2>
 
 	CSS uses the term <dfn export>overflow</dfn> to describe
 	the contents of a box
@@ -83,7 +84,7 @@ Types of overflow</h2>
 	The term might be interpreted as
 	elements or features that cause this overflow,
 	the non-rectangular region occupied by these features,
-	or, more commonly,
+	or, more commonly, as
 	the minimal rectangle that bounds that region.
 	A box's overflow is computed based on the layout and styling of the box itself
 	and of all descendants whose <a>containing block chain</a>
@@ -107,7 +108,7 @@ Types of overflow</h2>
 		<li><a>scrollable overflow</a>
 	</ul>
 
-<h3 id="ink">Ink overflow</h3>
+<h3 id="ink">Ink Overflow</h3>
 
 	The <dfn export>ink overflow</dfn> of a box
 	is the part of that box and its contents that
@@ -124,22 +125,24 @@ Types of overflow</h2>
 	etc.
 
 	Since some effects in CSS (for example, the blurs in
-	'text-shadow' [[CSS3TEXT]] and 'box-shadow' [[CSS3BG]])
+	'text-shadow' [[CSS-TEXT-3]] and 'box-shadow' [[CSS-BACKGROUNDS-3]],
+	which are theoretically infinite)
 	do not define what visual extent they cover, the extent
 	of the <a>ink overflow</a> is undefined.
 
 	The <dfn export>ink overflow region</dfn> is the non-rectangular area
-	occupied by the <a>ink overflow</a>, and the
-	<dfn export>ink overflow rectangle</dfn> is
-	the minimal rectangle whose axis is aligned to the box's axes
-	and contains the <a>ink overflow region</a>.
+	occupied by the <a>ink overflow</a>
+	of a box and its contents,
+	and the <dfn export>ink overflow rectangle</dfn> is
+	the minimal rectangle whose axes are aligned to the box's axes
+	and that contains the <a>ink overflow region</a>.
 	Note that the <a>ink overflow rectangle</a> is a rectangle
 	in the box's coordinate system, but might be non-rectangular
-	in other coordinate systems due to transforms [[CSS3-TRANSFORMS]].
+	in other coordinate systems due to transforms. [[CSS3-TRANSFORMS]]
 
 
 <h3 id="scrollable">
-Scrollable overflow</h3>
+Scrollable Overflow</h3>
 
 	The <dfn export>scrollable overflow</dfn> of a box is the
 	set of things extending outside of that box's padding edge
@@ -148,8 +151,8 @@ Scrollable overflow</h3>
 	The <dfn export>scrollable overflow region</dfn> is the non-rectangular region
 	occupied by the <a>scrollable overflow</a>, and the
 	<dfn export>scrollable overflow rectangle</dfn> is
-	the minimal rectangle whose axis is aligned to the box's axes
-	and contains the <a>scrollable overflow region</a>.
+	the minimal rectangle whose axes are aligned to the box's axes
+	and that contains the <a>scrollable overflow region</a>.
 
 	The <a>scrollable overflow region</a> is the union of:
 	<ul>
@@ -255,7 +258,7 @@ Scrollable overflow</h3>
 -->
 
 <h2 id="overflow-properties">
-Scrollable Overflow: the 'overflow-x', 'overflow-y', and 'overflow' properties</h2>
+Scrolling and Clipping Overflow: the 'overflow-x', 'overflow-y', and 'overflow' properties</h2>
 
 	These properties specify whether a box’s content
 	(including any <a>ink overflow</a>)
@@ -310,8 +313,8 @@ Scrollable Overflow: the 'overflow-x', 'overflow-y', and 'overflow' properties</
 	<dl dfn-for="overflow, overflow-x, overflow-y" dfn-type="value">
 		<dt><dfn>visible</dfn>
 		<dd>
-			There is no special handling of overflow, that is, it
-			may be rendered outside the box.
+			There is no special handling of overflow, that is,
+			the box’s content is rendered outside the box if positioned there.
 			The box is not a <a>scroll container</a>.
 
 		<dt><dfn>hidden</dfn>
@@ -357,35 +360,35 @@ Scrollable Overflow: the 'overflow-x', 'overflow-y', and 'overflow' properties</
 
 		<dt><dfn>auto</dfn>
 		<dd>
-			This value indicates that
-			the box’s content is clipped to the padding box,
-			but can be scrolled into view
-			(and therefore the box is a <a>scroll container</a>).
-			However, if the user agent uses a scrolling mechanism
+			Like ''overflow/scroll'' when the box has <a>scrollable overflow</a>;
+			like ''overflow/hidden'' otherwise.
+			Thus, if the user agent uses a scrolling mechanism
 			that is visible on the screen (such as a scroll bar or a panner),
-			that mechanism should only be displayed
+			that mechanism will only be displayed
 			if there is overflow.
 		</dl>
 
-	If the computed value of 'overflow' on a <a>block box</a> is not ''overflow/visible'',
+	If the computed value of 'overflow' on a <a>block box</a>
+	is not ''overflow/visible'',
 	it creates a new <a>block formatting context</a> for its content.
 
 <h3 id="overflow-propagation">
 Overflow Value Propagation</h3>
 
-	UAs must apply the 'overflow' property
-	set on the root element to the viewport.
-	When the root element is an [[!HTML]] <{html}> element
-	(including <a href="https://html.spec.whatwg.org/multipage/introduction.html#html-vs-xhtml">XML syntax for HTML</a>),
+	UAs must apply the 'overflow-*' values
+	set on the root element to the <a>viewport</a>.
+	However,
+	when the root element is an [[!HTML]] <{html}> element
+	(including <a href="https://html.spec.whatwg.org/multipage/introduction.html#html-vs-xhtml">XML syntax for HTML</a>)
+	whose 'overflow' value is ''overflow/visible'' (in both axes),
 	and that element has a <{body}> element as a child,
-	user agents must instead apply the 'overflow' property
-	from the first such child element to the viewport,
-	if the value on the root element is ''overflow/visible''.
-	The ''overflow/visible'' value when used for the viewport must be interpreted as ''overflow/auto''.
-	The element from which the value is propagated must have a used value for 'overflow' of ''overflow/visible''.
+	user agents must instead apply the 'overflow-*' values
+	of the first such child element to the viewport.
+	The element from which the value is propagated must then have
+	a used 'overflow' value of ''overflow/visible''.
 
-	If this application would result in the viewport having ''visible'' overflow,
-	the UA must instead treat the viewport as having ''overflow/auto'' overflow.
+	If ''overflow/visible'' is applied to the viewport,
+	it must be interpreted as ''overflow/auto''.
 
 <h3 id="scrollbar-layout">
 Scrollbars and Layout</h3>
@@ -408,10 +411,11 @@ Scrolling Origin, Direction, and Restriction</h3>
 	with respect to its border box,
 	prior to any user or programmatic scrolling that changes it,
 	is dependent on the box’s <a>writing mode</a>,
-	and is by default the <a>block-start</a>/</a>inline-start</a> edge
+	and is by default the <a>block-start</a>/<a>inline-start</a> edge
 	of the box’s <a>padding edge</a>.
 	However, the 'align-content' and 'justify-content' properties [[!CSS-ALIGN-3]]
-	can be used to change this.
+	can be used to change this,
+	see [[css-align-3#overflow-scroll-position]].
 
 	Due to Web-compatibility constraints
 	(caused by authors exploiting legacy bugs to surreptitiously hide content from visual readers but not search engines and/or speech output),