464970 - nsCSSBorderRenderer::AreBorderSideFinalStylesSame is too pessimistic

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: patch

When nsCSSBorderRenderer::AreBorderSideFinalStylesSame is given an aSides mask that doesn't include all the sides, it still checks any sides that aren't in the mask if they're after the first side that it does check.

I found this while debugging a reftest failure (pixel-rounding/border-width-5, border-width-6, and 2 others) that happens only on my machine.  It fixes the failure, but it's clearly not the real machine-specific problem.

Comment 1

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: static testcase for the X bug

Here's a testcase for the issue I was debugging; the pixel along the bottom edge, second from the left, ends up one shade off (127 rather than 128 in the green component).

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: <canvas> testcase for the X bug

Here's a <canvas> testcase for that same bug.  Attachment 348234 [details] [diff] fixes attachment 348252 [details], but not this one.

However, vlad's image surface build fixes this testcase but not attachment 348252 [details].

(I see the bug on both 32-bit and 64-bit firefox builds.)

Comment 3

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

(In reply to comment #2)
> However, vlad's image surface build fixes this testcase but not attachment
> 348252 [details].

That build is
https://build.mozilla.org/tryserver-builds/2008-11-13_19:[e-mail]-isurfgrrr/

Comment 4

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Comment on attachment 348234 [details] [diff] [review]
patch

This is a simple fix to make this function do what it says it does, and thus restore an optimization that makes a bunch of reftests pass on my machine.

Comment 5

[Mike Beltzner [:beltzner, not reading bugmail]]

Comment on attachment 348234 [details] [diff] [review]
patch

a191b2=beltzner

Comment 6

[(not currently active) Ted Mielczarek]

Pushed to m-c:
http://hg.mozilla.org/mozilla-central/rev/73bda3268799

Presumably you want to make these tests into reftests, so in-testsuite?

Comment 7

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Also needed to land http://hg.mozilla.org/mozilla-central/rev/e8bb73413554