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Align mspace/mpadded attribute parsing on Blink.
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See also https://chromium-review.googlesource.com/c/chromium/src/+/4120274
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@fred-wang
fred-wang committed Jan 6, 2023
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119 changes: 89 additions & 30 deletions index.html
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Expand Up @@ -2084,11 +2084,43 @@ <h4>Space <code>&lt;mspace&gt;</code></h4>
<dfn id="attribute-mspace-height" class="element-attr" data-dfn-for="mspace">height</dfn>,
<dfn id="attribute-mspace-depth" class="element-attr" data-dfn-for="mspace">depth</dfn>, if present, must
have a value that is a valid <a data-xref-type="css-type">&lt;length-percentage&gt;</a>.
An unspecified attribute, a percentage value, or an invalid value
is interpreted as <code>0</code>.
If one of the requested values calculated is negative then it is
treated as <code>0</code>.
</p>
<ul>
<li>
If the <code>width</code>
attribute is present, valid and not a percentage then
that attribute is used as a
<a data-cite="HTML/../#presentational-hints">presentational hint</a>
setting the element's
<a data-xref-type="css-property">width</a>
property to the corresponding value.
</li>
<li>
If the <code>height</code>
attribute is absent, invalid or a percentage then the requested
line-ascent is <code>0</code>.
Otherwise the requested line-ascent is the resolved
value of the <code>height</code> attribute, clamping
negative values to <code>0</code>.
</li>
<li>
If both the <code>height</code> and <code>depth</code> attributes
are present, valid and not a percentage then they are used as a
<a data-cite="HTML/../#presentational-hints">presentational hint</a>
setting the element's
<a data-xref-type="css-property">height</a>
property to the concatenation of the strings
"<code>calc(</code>", the <code>height</code> attribute value,
"<code> + </code>", the <code>depth</code> attribute value,
and "<code>)</code>".
If only one of these attributes is
present, valid and not a percentage then it is treated as a
<a data-cite="HTML/../#presentational-hints">presentational hint</a>
setting the element's
<a data-xref-type="css-property">height</a>
property to the corresponding value.
</li>
</ul>
<div class="example" id="mspace-example">
<p>In the following example, [^mspace^] is used to
force spacing within the formula (a 1px blue border is
Expand All @@ -2107,12 +2139,14 @@ <h4>Space <code>&lt;mspace&gt;</code></h4>
Otherwise,
the <code>&lt;mspace&gt;</code> element is laid out as shown on
<a href="#figure-box-mspace"></a>.
The <a>min-content inline size</a> and
<a>max-content inline size</a> of the math content are
equal to the requested inline size.
The <a>inline size</a>, <a>line-ascent</a> and <a>line-descent</a> of the math content
are respectively
the requested inline size, line-ascent and line-descent.
The <a>min-content inline size</a>,
<a>max-content inline size</a> and <a>inline size</a> of the math
content are equal to the resolved value of the
<a data-xref-type="css-property">width</a> property.
The <a>block size</a> of the math content is equal to the resolved
value of the <a data-xref-type="css-property">height</a> property.
The <a>line-ascent</a> of the math content is equal to the
requested line-ascent determined above.
</p>
<figure id="figure-box-mspace">
<img src="figures/mspacebox.svg">
Expand Down Expand Up @@ -3162,33 +3196,58 @@ <h5>Inner box and requested parameters</h5>
<a>generates an anonymous &lt;mrow&gt; box</a> called the
<dfn>mpadded inner box</dfn> with parameters called
inner inline size, inner <a>line-ascent</a> and inner line-descent.
</p>
<p>
The requested <code>&lt;mpadded&gt;</code>
parameters are determined as follows:
</p>
<ul class="algorithm">
<li>If the <code>width</code> (respectively <code>height</code>,
<code>depth</code>, <code>lspace</code>, <code>voffset</code>)
attribute is absent, invalid or a percentage
then the requested width
(respectively height, depth, lspace, voffset)
is the inner inline size
(respectively inner <a>line-ascent</a>, inner line-descent,
<code>0</code>,
<code>0</code>).
<li>
The requested width
is the resolved value of the
<a data-xref-type="css-property">width</a> property.
If the <code>width</code>
attribute is present, valid and not a percentage then
that attribute is used as a
<a data-cite="HTML/../#presentational-hints">presentational hint</a>
setting the element's
<a data-xref-type="css-property">width</a>
property to the corresponding value.
</li>
<li>
If the <code>height</code>
attribute is absent, invalid or a percentage then the requested
height is the inner <a>line-ascent</a>.
Otherwise the requested height is the resolved
value of the <code>height</code> attribute, clamping
negative values to <code>0</code>.
</li>
<li>
If the <code>depth</code>
attribute is absent, invalid or a percentage then the requested
depth is the inner <a>line-ascent</a>.
Otherwise the requested depth is the resolved
value of the <code>depth</code> attribute, clamping
negative values to <code>0</code>.
</li>
<li>Otherwise the requested width
(respectively height, depth, lspace, voffset) is the resolved
value of the <code>width</code> attribute
(respectively <code>height</code>, <code>depth</code>,
<code>lspace</code>, <code>voffset</code> attributes).
If one of the requested width, depth, height or lspace values
is negative then it is treated as <code>0</code>.
<li>
If the <code>lspace</code>
attribute is absent, invalid or a percentage then the requested
lspace is 0. Otherwise the requested lspace is the resolved
value of the <code>lspace</code> attribute, clamping
negative values to <code>0</code>.
</li>
<li>
If the <code>voffset</code>
attribute is absent, invalid or a percentage then the requested
voffset is 0. Otherwise the requested voffset is the resolved
value of the <code>voffset</code> attribute.
<div class="note">
Negative <code>voffset</code> values are not clamped to
<code>0</code>.
</div>
</li>
</ul>
<div class="note">
Negative <code>voffset</code> values are not clamped to
<code>0</code>.
</div>
</section>
<section>
<h5>Layout of <code>&lt;mpadded&gt;</code></h5>
Expand Down

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