Bug 194940 – Fix unitless usage of mathsize

• Status: RESOLVED
• Resolution: FIXED
• Component: MathML

[Rob Buis]

Computation of unitless values for mathsize is wrong, causing these tests to fail:
* http://www.w3c-test.org/mathml/relations/css-styling/lengths-1.html
* http://www.w3c-test.org/mathml/relations/css-styling/lengths-3.html

[Rob Buis]

Created attachment 362708 [details]
Patch

[Frédéric Wang (:fredw)]

Comment on attachment 362708 [details]
Patch

Great thanks. I guess it's a bit hacky and I think Gecko has similar hacks. Probably nonzero unitless values should not be supported.

[WebKit Commit Bot]

Comment on attachment 362708 [details]
Patch

Clearing flags on attachment: 362708

Committed r241942: <https://trac.webkit.org/changeset/241942>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/48306931>

[Darin Adler]

Oh, no! Don’t add more uses of String::format!

[Frédéric Wang (:fredw)]

(In reply to Frédéric Wang (:fredw) from comment #2)
> Comment on attachment 362708 [details]
> Patch
> 
> Great thanks. I guess it's a bit hacky and I think Gecko has similar hacks.
> Probably nonzero unitless values should not be supported.

Let's ask the MathML CG to remove these special parsing so that we don't need these hacks anymore:
https://github.com/mathml-refresh/mathml/issues/24
https://github.com/mathml-refresh/mathml/issues/7

[Frédéric Wang (:fredw)]

Comment on attachment 362708 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=362708&action=review

> Source/WebCore/mathml/MathMLElement.cpp:105
> +        return String::format("%.3f%%", unitlessValue * 100.0);

I suspect this is not super reliable. I seems to get rounding errors with my local build.

[Rob Buis]

(In reply to Darin Adler from comment #6)
> Oh, no! Don’t add more uses of String::format!

Oops, I was not aware of https://bugs.webkit.org/show_bug.cgi?id=194752! Maybe it could be renamed to deprecatedFormat. I am happy to fix it in a follow up though.

[Rob Buis]

Reopening to attach new patch.

[Rob Buis]

Created attachment 362888 [details]
Patch

[Rob Buis]

Already fixed.

[Rob Buis]

Reopening to attach new patch.

[Rob Buis]

Created attachment 362890 [details]
Patch

[Darin Adler]

Well, I re-landed my patch that fixes it. You are welcome to refine further.

[Rob Buis]

Hi Darin,

(In reply to Darin Adler from comment #15)
> Well, I re-landed my patch that fixes it. You are welcome to refine further.

Thanks for the heads up. We are happy with the change so I will close this bug. Note that we are still evaluating usage of unitless values in mathsize for the next version of the  MathML spec, but if we drop support we will likely do it in a new bug.