379414 - Animated image rendered incorrectly; subframe shouldn't be tiled

Status: RESOLVED FIXED

(Core :: Graphics: ImageLib, defect)

Description

[Justin Dolske [:Dolske]]

The upcoming attachments are 2 frame animations. The first frame is the Firefox logo, and the second frame is a 16x16 colorwheel icon, offset to the center of the frame.

* ok-keep.png works as expected. The first frame's disposal method is "keep", and the animation is the little colorwheel blinking on/off on top of the logo.

* bad-clear.png does not work as expected. The first frame's disposal method is "clear". When the second frame is displayed, the logo from frame 1 is successfully cleared but the icon in frame two is tiled to the right and down, when it should only be drawn once.

The bug also happens with the "revert" disposal method. And it only seems to happen when the image for the previous frame was larger than the current frame... If a 3rd frame (16x16) frame is added, it's rendered fine.

This might be resolved by bug 317748?

Comment 1

[Justin Dolske [:Dolske]]

Attachment: Working APNG

Comment 2

[Justin Dolske [:Dolske]]

Attachment: Incorrectly rendered APNG

Comment 3

[Alfred Kayser]

Strange thing is that it works fine in Windows. 
How can if the image handling is Thebes/Cairo based, there be such a difference between Mac and Windows?
Also the image decoder and container is the same for both platforms, so the problem is probably somewhere in the handling of image drawing for MacOS?

Comment 4

[Andrew Smith]

It also seems to work fine on Linux. If I can find a mac I'll take a look.

Comment 5

[Justin Dolske [:Dolske]]

Attachment: GIF showing the same problem?

I'm not sure if this is the same bug, but I noticed that the original "spinfox" GIF from http://burntelectrons.org/moz/spinfox/ also seems to be showing a tiling quirk, at least on OS X. Probably not specific to APNG, then...

Comment 6

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

This is a bug in the mac image rendering code; it'll be fixed once we update cairo to 1.4.8 (where the underlying bug is fixed). 

Comment 7

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Should be fixed now.