Bug 276026 – [MathML] <mfrac> with out-of-flow numerator/denominator produces unexpected result

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[zalan]

<rdar://130757408>

[zalan]

Created attachment 471770 [details]
[fast-cq]Patch

[EWS]

Committed 280505@main (c37d84f4267d): <https://commits.webkit.org/280505@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 471770 [details].

[Frédéric Wang (:fredw)]

Comment on attachment 471770 [details]
[fast-cq]Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=471770&action=review

> COMMIT_MESSAGE:8
> +(Alternatively we can mark such content as invalid as they are certainly expected to be inflow boxes, but the rest of the MathML renderers follow this logic.)

For reference the behavior described in MathML Core (  https://www.w3.org/TR/mathml-core/#fractions-mfrac ):

> If the <mfrac> element has less or more than two in-flow children, its layout algorithm is the same as the mrow element. Otherwise, the first in-flow child is called numerator, the second in-flow child is called denominator and the layout algorithm is explained below. 

We should probably review all the MathML elements and see if they follow this logic.

[zalan]

(In reply to Frédéric Wang (:fredw) from comment #3)
> Comment on attachment 471770 [details]
> [fast-cq]Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=471770&action=review
> 
> > COMMIT_MESSAGE:8
> > +(Alternatively we can mark such content as invalid as they are certainly expected to be inflow boxes, but the rest of the MathML renderers follow this logic.)
> 
> For reference the behavior described in MathML Core ( 
> https://www.w3.org/TR/mathml-core/#fractions-mfrac ):
> 
> > If the <mfrac> element has less or more than two in-flow children, its layout algorithm is the same as the mrow element. Otherwise, the first in-flow child is called numerator, the second in-flow child is called denominator and the layout algorithm is explained below. 
Thank you!
I did a quick search before submitting this patch and landed on the spec, hence my hesitation in the changelog entry.

> 
> We should probably review all the MathML elements and see if they follow
> this logic.
Yeah, we should certainly do that!

[Frédéric Wang (:fredw)]

(In reply to zalan from comment #4)
> > We should probably review all the MathML elements and see if they follow
> > this logic.
> Yeah, we should certainly do that!

OK apparently I already had opened bug 179739 for that and more recently MathML Core specified how to handle it. I'll propose this task to an Igalia's Coding Experience student.

[zalan]

(In reply to Frédéric Wang (:fredw) from comment #5)
> (In reply to zalan from comment #4)
> > > We should probably review all the MathML elements and see if they follow
> > > this logic.
> > Yeah, we should certainly do that!
> 
> OK apparently I already had opened bug 179739 for that and more recently
> MathML Core specified how to handle it. I'll propose this task to an
> Igalia's Coding Experience student.
Awesome! Thank you for taking care of this!