409878 - Garbage displayed for part of bluebar.gif animation

Status: VERIFIED FIXED

(Core :: Graphics: ImageLib, defect)

Description

[Justin Kerk]

The animated GIF at http://www.alexchiu.com/cell/bluebar.gif displays garbage for part of its duration using current Minefield nightlies. This does not occur in Firefox 2 or IE7. Saving the file to the local disk and opening from there makes no difference. Microsoft GIF Animator gives an error that the file may be corrupt when I try to open it, so that may be related to the problem.

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2007122605 Minefield/3.0b3pre ID:2007122605

Comment 1

[Ria Klaassen (not reading all bugmail)]

Is caused by Bug 366465.

Comment 2

[Alfred Kayser]

Interesting, another corrupt GIF that is showing corrupt display...
I remember something about garbage in = garbage out.
But apparently the old code was less sensitive to garbage like this.

Comment 3

[Alfred Kayser]

Attachment: V1: Postpose 'AppendFrame' till we are sure that we have a real frame

Because the attached gif file does provide an header for the next frame, but no actual frame data, and that before (long, long ago) the frame was only allocated when actual frame data (the first row of it) was detected, we now also need to prevent adding empty frames to the imageContainer.

So, postpose 'AppendFrame' till 'EndImageFrame', so that we can skip it if there is no image data at all.

The memset is to clear any rows not set from image source data (this only applies to animation frames (so not the first one)).

Comment 4

[Alfred Kayser]

Attachment: V2: Only postpone for animation frames to dynamic update of the first frame working

Comment 5

[Alfred Kayser]

The first patch didn't pass the gifbuster test (http://webtools.mozilla.org/buster/gif-buster/gif-buster.html).

Comment 6

[Reed Loden [:reed]]

Comment on attachment 294787 [details] [diff] [review]
V2: Only postpone for animation frames to dynamic update of the first frame working

stuart's review is enough here. I'll land this shortly.

Comment 7

[Reed Loden [:reed]]

Checking in modules/libpr0n/decoders/gif/nsGIFDecoder2.cpp;
/cvsroot/mozilla/modules/libpr0n/decoders/gif/nsGIFDecoder2.cpp,v  <--  nsGIFDecoder2.cpp
new revision: 1.91; previous revision: 1.90
done

Comment 8

[Alfred Kayser]

Ok, thanks!

Comment 9

[Steve England [:stevee]]

This is a longshot, but is there any chance this bug could have caused bug 412294 or bug 412863?

Comment 10

[Alfred Kayser]

See bug 411874 for a patch for the problem caused by this bug.