906704 - rotated text with synthetic bolding causes infinite loop in text drawing

Status: RESOLVED FIXED

(Core :: Graphics: Text, defect)

Comment 1

[(no longer active)]

Attachment: Profile

Comment 2

[(no longer active)]

Hey Alice, any chance you could see if you can narrow this down please?  Thanks a lot!

Comment 3

[Alice0775 White]

(In reply to :Ehsan Akhgari (needinfo? me!) from comment #2)
> Hey Alice, any chance you could see if you can narrow this down please? 
> Thanks a lot!

I cannot reproduce the problem on Windows7 and Ubuntu.
And I cannot test this on Mac because I do not have Mac.

Comment 4

[(no longer active)]

Thanks, Alice!

Jeff, can you please see if you can make this bug actionable?

Comment 5

[Jeff Muizelaar [:jrmuizel]]

It looks like we are stuck in gfxFont::Draw() calling GlyphBufferAzure::Flush() for ever.

Comment 6

[John Daggett (:jtd)]

Simplified testcase:
http://people.mozilla.org/~jdaggett/tests/syntheticbold-rotated.html

Two problems here: the matrix code in gfxContext::UserToDevice(const gfxSize& size) is wrong (yikes!) and the synthetic bolding code isn't handling the singular matrix case, so it ends up with stamps = huge number and this causes an infinite loop while drawing.  Scary part is this bug has been there since Bas added it in early 2012.

Comment 7

[John Daggett (:jtd)]

Attachment: patch, fix matrix calc bug

Fix the matrix math error and check the result of CalcXScale.

Comment 8

[John Daggett (:jtd)]

Attachment: patch, add reftest for the rotated synthetic bold case

Reftest based on simplified testcase.  This will cause the infinite loop in current trunk code and render correctly with patch.

Comment 9

[Jonathan Kew [:jfkthame]]

Looks like this is the same issue Jesse filed in bug 895051. I'll dupe that report to this one, given that the fix is being done here.

Comment 11

[John Daggett (:jtd)]

Pushed to inbound:
https://hg.mozilla.org/integration/mozilla-inbound/rev/3b40bd9e75c5
https://hg.mozilla.org/integration/mozilla-inbound/rev/1bd4a6e58e21

Comment 12

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/3b40bd9e75c5
https://hg.mozilla.org/mozilla-central/rev/1bd4a6e58e21

Comment 15

[Joshua Mitchell (Inactive)]

Issue is resolved - clearing old keywords - qa-wanted clean-up