444990 - Artifacts (black lines) when displaying very large jpegs with scaling on

Status: UNCONFIRMED

(Core :: General, defect)

Description

[Scott Burns]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en; rv:1.8.1.14) Gecko/20080512 Camino/1.6.1 (like Firefox/2.0.0.14)
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en; rv:1.8.1.14) Gecko/20080512 Camino/1.6.1 (like Firefox/2.0.0.14)

I was browsing interfacelift.com this morning for wallpapers.  When downloading very large images (2560x1600), I noticed two black lines displayed near the bottom of the image in all the pictures, at the exact same spots.  This does not occur with smaller images (1920x1200, for instance).  However, if you click on the image (to see it in full size) and click on it again (to scale the image again), the two lines are gone.  

At first I thought it could be a problem with interfacelift.com, but I did a google image search, found a 2560x1600 image, and the same two black lines showed up.  

Because a double-click will resolve the lines, it's not a big problem, but it might be worth looking at as monitor resolution continues to increase.

Reproducible: Always

Steps to Reproduce:
1.Download a 2560x1600 jpeg image from the internet.
2.Camino displays the image with two black lines in it toward the bottom of the image.
Actual Results:  
Two black lines in the picture.

Expected Results:  
Not display the two black lines.

I would not consider this a major bug at all.

Comment 1

[Chris Lawson (gone)]

I've seen this sort of thing before, and I'm not sure what causes it, but I *am* sure it's a bug in the Core image scaling code rather than anything Camino-specific.

Comment 2

[Smokey Ardisson (offline for a while; not following bugs - do not email)]

I can't reproduce this, but based on the description I think I've seen it, too.

--> Core:General for further triage.

Comment 3

[Michael Moy]

I'm unable to reproduce this on Firefox 3.0 (Intel Mac OSX). Do you have a particular image that reproduces the problem or do you see it on 3.0?

Comment 4

[Scott Burns]

I'm not sure of Firefox's architecture in OS X, but as Chris Lawson points out above, the bug is most likely in OS X's Core Image API (which Camino uses), and if Firefox doesn't use this, I highly doubt it would manifest in Firefox.

Comment 5

[Chris Lawson (gone)]

I haven't noticed this in a long time, and I haven't noticed it at all since switching to Intel a couple months ago. I'd be shocked if it wasn't present in Firefox, though. It was never particularly reproducible when I was seeing it regularly, either.

By the way, "Core image" in the context of comment 1 means "Gecko" (note the component this bug is assigned to), not the proper name "Core Image" (the Mac OS X API that Scott is referring to in comment 4). Sorry for the confusion; I don't believe any Gecko browsers use any Core Image code on OS X yet.

Comment 6

[Scott Burns]

Chris, thanks for clearing that up.  I figured that because Camino is a more "mac-ified" version of Firefox that it might use deep OS X APIs, but that makes no sense after thinking about it more (I'm guessing the interface uses Cocoa UI APIs but the rendering engine is the same between Firefox and Camino).

I have not seen this bug in a while either.  I'm currently using Camino 2.0b2.

Comment 7

[Grant Galitz]

Seems to be related to bug reports:
https://bugzilla.mozilla.org/show_bug.cgi?id=490997
https://bugzilla.mozilla.org/show_bug.cgi?id=598890

Comment 8

[Mardeg]

PPC builds are no longer being created, so it's hard to say whether the fix in bug 468496 would have helped here.