cb22hh Reporter
	Description • 16 years ago

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.0.3) Gecko/2008092417 Firefox/3.0.3
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:1.9.0.3) Gecko/2008092417 Firefox/3.0.3

<mtable> elements containing tags like <mspace width="0.5em" /> result in truncated tables. Bug was observed on Linux and WinXP computers with STIXfonts installed.

The attachments give an example. The first attachment contains the xhtml code while the second one shows a screenshot of the rendered equation.

Reproducible: Always

Steps to Reproduce:
Open the attached xhtml-file with Firefox.
Actual Results:  
Bracket closes too far on the left.

Expected Results:  
Bracket should be further on the right side.

	extremesheep
	Comment 4 • 16 years ago

I can confirm his case. I reduced it as much as I could.

I think this is technically a regression because it rendered correctly in Firefox 2.0.0.16 (it would complain about lack of fonts though) but it seems to have been rewritten since Firefox 3.

Rules for variables inside parenthesis seemed to be added in between these trunks.

testcase broken:
2008-02-26-04-trunk

testcase gives same results as Firefox 3.0.3 & latest trunk (10-10-2008)
2008-02-27-04-trunk

	extremesheep
	Comment 5 • 16 years ago

Oh and I tested it on windows xp sp3

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.3) Gecko/2008092417 Firefox/3.0.3

	Matt
	Comment 6 • 15 years ago

I tried to check bonsai and this is what I found.

http://bonsai.mozilla.org/cvsquery.cgi?treeid=default&module=all&branch=HEAD&branchtype=match&dir=&file=&filetype=match&who=&whotype=match&sortby=Date&hours=2&date=explicit&mindate=2008-02-26+03%3A00%3A00&maxdate=2008-02-27+05%3A00%3A00&cvsroot=%2Fcvsroot

I think it points to this bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=363240

This bug is very similar to the following:
https://bugzilla.mozilla.org/show_bug.cgi?id=428906

	Martijn
	Comment 7 • 15 years ago

There seems to be a general problem with bounding box size of MathMl expressions. mspace causes bounding box to be too small. mfenced causes bounding box to be too large. See the example on http://www.algebrakit.nl/ff.xhtml

	Frédéric Wang (:fredw) Assignee
	Comment 8 • 12 years ago

Davide Cervone is trying to add a workaround in MathJax for the <mlabeledtr> bug in Gecko (and other rendering engines). He hit the present bug for <mpadded> and <mspace>.

If equations are labeled via <mlabeledtr>, then many formulas can be put in tables. In particular the use of <mspace>'s is common and things like

$$ \f(n) = f(n-1) + f(n-2) \quad \text{for } n>2 $$ 

would make the formula width badly computed and it will overlap with the label.

	Frédéric Wang (:fredw) Assignee
	Comment 10 • 12 years ago

@Karl: do you know what's happening here? I think the issue is a bit different than for the width of token elements (bug 415413). Perhaps we could map mspace@width to style on the content/ side? Can using the flexbox model help (that's what Webkit folks do)?

	Frédéric Wang (:fredw) Assignee
	Comment 11 • 12 years ago

Mapping mspace@width to style seems to fix the two testcases.

	Karl Tomlinson (:karlt)
	Comment 12 • 12 years ago

(In reply to Frédéric Wang (:fredw) from comment #10)
> @Karl: do you know what's happening here?

I'm guessing this is related to nsMathMLmspaceFrame implementing Reflow, but not Place and so nsMathMLContainerFrame's intrinsic width calculations are not taking into account the mspace element.

> I think the issue is a bit
> different than for the width of token elements (bug 415413).

Yes.

> Perhaps we could map mspace@width to style on the content/ side?

The may be the right thing to do anyway, but an AttributeChanged method may also be handling that.

> Can using the flexbox model help (that's what Webkit folks do)?

I'm not familiar with flexbox or how it is used in Webkit's MathML.

	Frédéric Wang (:fredw) Assignee
	Comment 13 • 12 years ago

(In reply to Karl Tomlinson (:karlt) from comment #12)
> > Perhaps we could map mspace@width to style on the content/ side?
> 
> The may be the right thing to do anyway, but an AttributeChanged method may
> also be handling that.

That would be better if we can fix that on the layout/ side. The fix won't work for mpadded.

> I'm guessing this is related to nsMathMLmspaceFrame implementing Reflow, but
> not Place and so nsMathMLContainerFrame's intrinsic width calculations are
> not taking into account the mspace element.
> 

That's what I was just reading. However, mpadded implements Place and the bug also happens if you replace <mspace width="1em"> by <mpadded width="1em">. The only difference I see is that mpadded place its children first.

I'll try to do more testing when I have time.

	Frédéric Wang (:fredw) Assignee
	Comment 14 • 12 years ago

OK, the Place function of mpadded was not calling ProcessAttribute. I've implemented MeasureForWidth for mpadded and mspace and that seems to fix the testcases. Some reftest failures happened after this change, but that was due to errors in the test pages.

	Frédéric Wang (:fredw) Assignee
	Comment 15 • 12 years ago

Updated patch. Just replacing

NS_IMETHODIMP

by

/* virtual */ nsresult

to prevent compilation errors on Windows.

https://tbpl.mozilla.org/?tree=Try&rev=075fc28d83f4
https://tbpl.mozilla.org/?tree=Try&rev=4904985e03b9

	Ryan VanderMeulen [:RyanVM]
	Comment 16 • 12 years ago

https://hg.mozilla.org/integration/mozilla-inbound/rev/bb5f246f127f

	Ed Morley [:emorley]
	Comment 17 • 12 years ago

https://hg.mozilla.org/mozilla-central/rev/bb5f246f127f