Bug 126842

Summary: Only skip stretchy operators when determining the stretch height
Product: WebKit Reporter: Frédéric Wang (:fredw) <fred.wang>
Component: MathMLAssignee: Frédéric Wang (:fredw) <fred.wang>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, cfleizach, commit-queue, dbarton, esprehn+autocc, glenn, kondapallykalyan, mrobinson
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Bug Depends on: 99620, 119043    
Bug Blocks: 124838    
Attachments:
Description Flags
testcase
none
Patch
none
Patch
cfleizach: review+
Patch + 119043 for testing none

Description Frédéric Wang (:fredw) 2014-01-12 06:37:34 PST 
> >> Source/WebCore/rendering/mathml/RenderMathMLRow.cpp:59
> >> +        // FIXME: Only skip renderMo if it is stretchy.
> > 
> > Bug? :-)
> 
> Fred, I'm not familiar with this issue. If you open a bug for it and write a description I can add a link here.

Sorry, I just realized that I didn't reply to this. I think the idea is that this loop consider the height of children that are not (embellished) operators in order to determine the stretch size. Then a second loop stretch the (embellished) operators to that size. The FIXME comment says that the first loop should only skip *stretchy* operators, so that e.g. <mo>+</mo> is taken into account in the determination of the stretch size. Probably, the second loop should skip these non-stretchy operators too.

I'll open a bug for that later, but it seems to me that this should be fixed after the operator dictionary implementation anyway, so that we know exactly which operator is stretchy.

See also bug 119043 for related improvements to this stretch code (size and alignment).
Comment 1 Frédéric Wang (:fredw) 2014-02-20 02:05:48 PST 
Created attachment 224735 [details]
testcase

In the attached testcase, the brace should stretch to cover the size of the large <mo>p</mo>.
Comment 2 Frédéric Wang (:fredw) 2014-02-20 02:40:26 PST 
Created attachment 224738 [details]
Patch

Here is a simple patch that applies on top of bug 119043.
Comment 3 Frédéric Wang (:fredw) 2014-02-21 02:17:04 PST 
Created attachment 224846 [details]
Patch
Comment 4 Frédéric Wang (:fredw) 2014-02-21 06:09:56 PST 
Comment on attachment 224846 [details]
Patch

Asking review. The test will fail because this depends on bug 119043.
Comment 5 Frédéric Wang (:fredw) 2014-02-22 00:31:37 PST 
Created attachment 224954 [details]
Patch + 119043 for testing
Comment 6 chris fleizach 2014-02-22 01:25:09 PST 
Comment on attachment 224846 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=224846&action=review

> Source/WebCore/ChangeLog:8
> +        The MathML code only takes into account non-mo children for the computation of the stretch size. Thus change includes non-stretchy mo in that computation. A new test is added into mathml/presentation/stretchy-depth-height.html.

thus -> this

> Source/WebCore/rendering/mathml/RenderMathMLRow.cpp:65
> +            // We exclude stretchy operators from the computation of the stretch size.

I would add the why you're skipping stretchy operators to the comment here as well.
Comment 7 Frédéric Wang (:fredw) 2014-02-22 02:16:03 PST 
Committed r164538: <http://trac.webkit.org/changeset/164538>