[css-transforms-1] Add stroke-box and content-box to transform-box and align box mapping. w3c#999

Author: dirkschulze

css-transforms-1/Overview.bs

@@ -111,7 +111,7 @@ This coordinate space can be modified with the 'transform' property. Using trans
 Module Interactions {#module-interactions}
 ------------------------------------------
 
-This module defines a set of CSS properties that affect the visual rendering of elements to which those properties are applied; these effects are applied after elements have been sized and positioned according to the <a href="https://www.w3.org/TR/CSS2/visuren.html">visual formatting model</a> from [[!CSS2]]. Some values of these properties result in the creation of a <a href="https://www.w3.org/TR/CSS2/visuren.html#containing-block">containing block</a>, and/or the creation of a <a spec="css21">stacking context</a>.
+This module defines a set of CSS properties that affect the visual rendering of elements to which those properties are applied; these effects are applied after elements have been sized and positioned according to the <a href="https://www.w3.org/TR/CSS2/visuren.html">visual formatting model</a> from [[!CSS2]]. Some values of these properties result in the creation of a <a href="https://www.w3.org/TR/CSS2/visuren.html#containing-block">containing block</a>, and/or the creation of a <a>stacking context</a>.
 
 Transforms affect the rendering of backgrounds on elements with a value of ''fixed'' for the 'background-attachment' property, which is specified in [[!CSS3BG]].
 
@@ -416,7 +416,7 @@ Transform reference box: the 'transform-box' property {#transform-box}
 
 <pre class='propdef'>
 Name: transform-box
-Value: border-box | fill-box | view-box
+Value: content-box | border-box | fill-box | stroke-box | view-box
 Initial: view-box
 Applies to: [=transformable elements=]
 Inherited: no
@@ -429,20 +429,24 @@ Animatable: no
 All transformations defined by the 'transform' and 'transform-origin' property are relative to the position and dimensions of the <dfn>reference box</dfn> of the element. The [=reference box=] is specified by one of the following:
 
 <dl dfn-for=transform-box>
+	: <dfn dfn-type=value>content-box</dfn>
+	:: Uses the content box as reference box. The reference box of a table is the border box of its <a href="https://www.w3.org/TR/CSS21/tables.html#model">table wrapper box</a>, not its table box.
+
 	: <dfn dfn-type=value>border-box</dfn>
 	:: Uses the border box as reference box. The reference box of a table is the border box of its <a href="https://www.w3.org/TR/CSS21/tables.html#model">table wrapper box</a>, not its table box.
 
 	: <dfn dfn-type=value>fill-box</dfn>
 	:: Uses the <a>object bounding box</a> as reference box.
 
+	: <dfn dfn-type=value>stroke-box</dfn>
+	:: Uses the <a>stroke bounding box</a> as reference box.
+
 	: <dfn dfn-type=value>view-box</dfn>
 	::  Uses the nearest <a href="https://www.w3.org/TR/SVG11/intro.html#TermSVGViewport">SVG viewport</a> as reference box.
 
 		If a {{viewBox}} attribute is specified for the <a href="https://www.w3.org/TR/SVG11/intro.html#TermSVGViewport">SVG viewport</a> creating element:
 		* The reference box is positioned at the origin of the coordinate system established by the {{viewBox}} attribute.
 		* The dimension of the reference box is set to the <em>width</em> and <em>height</em> values of the {{viewBox}} attribute.
-
-    Issue(w3c/csswg-drafts#999): Follow used value definition of Fill and Stroke specs/SVG2?
 </dl>
 
 For the SVG <{pattern}> element, the reference box gets defined by the <{pattern/patternUnits}> attribute [[!SVG2]].
@@ -453,10 +457,9 @@ For the SVG <a element>clipPath</a> element, the reference box gets defined by t
 
 A reference box adds an additional offset to the origin specified by the 'transform-origin' property.
 
-For SVG elements without an associated CSS layout box, the [=used value=] for ''transform-box/border-box'' is ''transform-box/view-box''.
-
-For elements with an associated CSS layout box, the [=used value=] for ''transform-box/fill-box'' and ''transform-box/view-box'' is ''transform-box/border-box''.
+For SVG elements without associated CSS layout box, the [=used value=] for ''transform-box/content-box'' is ''transform-box/fill-box'' and for ''transform-box/border-box'' is ''transform-box/stroke-box''.
 
+For elements with associated CSS layout box, the [=used value=] for ''transform-box/fill-box'' is ''transform-box/content-box'' and for ''transform-box/stroke-box'' and ''transform-box/view-box'' is ''transform-box/border-box''.
 
 The SVG <a element-attr for>transform</a> Attribute {#svg-transform}
 ====================================================================
@@ -1472,6 +1475,7 @@ The following changes were made since the <a href="https://www.w3.org/TR/2017/WD
 * Be more specific about computation of [=transformation matrix=] and [=current transformation matrix=].
 * Define reference box for paint servers and <{clipPath}> element.
 * Specify behavior of transform presentation attribute with 3-value-rotate as start or end value of a transition.
+* Add ''transform-box/stroke-box'' and ''transform-box/content-box'' to 'transform-box'. Align box mapping behavior across all specifications.
 * Editorial changes.
 
 <h2 class=no-num id='acknowledgments'>Acknowledgments</h2>