739490 - Incorrect border painting on the edge of surfaces

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Matt Woodrow (:mattwoodrow)]

Attachment: Force invalidation

When we attempt to paint a surface, with an nsDisplayBorder starting from the first pixel that *isn't* visible on the surface, we end up drawing single bit difference to the edge pixels of the surface.

Attached is an existing reftest, modified to invalidate that reproduces this on OSX with GL layers. Not sure what other platforms are affected by this, running tryserver builds now.

See https://tbpl.mozilla.org/php/getParsedLog.php?id=10379707&tree=Try&full=1 for an example failure.

Try server: https://tbpl.mozilla.org/?tree=Try&pusher=[e-mail]

This is affecting DLBI since changes to paint timing make this reftest (and others) fail, without the MozReftestInvalidate change.

Ideas here would be appreciated

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Odd. This is Mac-only?

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Oh, you said in comment #0 you don't know yet.

Comment 3

[Matt Woodrow (:mattwoodrow)]

Thinking about it, this might only fail on mac (opengl), even if it isn't necessarily limited to that.

It appears to be related to drawing around the edge of the surface, since modifying the test and removing the modifications to the last row of text moves the broken border painting up to the second to last line instead.

OpenGL layers are the only backend (I believe) that creates a separate surface for modifications and then uploads, other backend are drawing directly into the existing surface.

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Should we work around it by giving the temporary surface a 1px extra margin?

Comment 5

[Matt Woodrow (:mattwoodrow)]

Attachment: Pad temporary surfaces with OpenGL layers on mac

This feels like pretty bad wallpapering :(

Fixes the bug though.

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Comment on attachment 609603 [details] [diff] [review]
Pad temporary surfaces with OpenGL layers on mac

Review of attachment 609603 [details] [diff] [review]:
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Does the problem not occur on the top and left edges?

Comment 7

[Robert O'Callahan (:roc) (email my personal email if necessary)]

BTW, please add a big comment explaining why you're adding 1 there!

Comment 8

[Matt Woodrow (:mattwoodrow)]

> Does the problem not occur on the top and left edges?

It doesn't appear to, no.

Comment 9

[Matt Woodrow (:mattwoodrow)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2841b49cfb16

Comment 10

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

https://hg.mozilla.org/mozilla-central/rev/2841b49cfb16