344771 - Image scaling is broken - random data displayed

Status: RESOLVED WORKSFORME

(Core :: Graphics: ImageLib, defect)

Description

[Gervase Markham [:gerv]]

Build ID: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a1) Gecko/20060714 Minefield/3.0a1
(but also seen in a build from the 11th of July)

I'm getting display corruption with some PNG images - specifically the central map  on http://www.thebiblesite.org/, and all map images on http://www.sasi.group.shef.ac.uk/worldmapper/.

Instead of the image, what I get seems to be some random data from my X server's image cache. I've seen bits of browser windows, images previously viewed in the browser, other windows such as my console (even when not visible on screen), my taskbar and so on. Please see the attached screenshot for an example.

Having made a reduced test case, it only happens when the image is being scaled by the browser. However, this is not a sufficient condition - I've tried replacing the image with other images, and they scale fine. So it must be some characteristic of the PNG triggering the problem. I will attach my testcase.

The particular random data chosen stays the same on a particular page, but changes if I Shift-Reload it.

Comment 1

[Gervase Markham [:gerv]]

Attachment: PNG file for testcase - source is http://www.sasi.group.shef.ac.uk/worldmapper/images/smallpng/18.png

Comment 2

[Gervase Markham [:gerv]]

Attachment: Testcase

Comment 3

[Gervase Markham [:gerv]]

Attachment: Screenshot of problem

This is a screenshot of the testcase attached to this bug in my browser. Where you should see a map, you see some random data from what I assume must be the X server's image cache. (Note: I've seen data which doesn't belong to the browser, so it can't be a Firefox cache of any sort.)

Comment 4

[Gervase Markham [:gerv]]

It seems that it's not just PNGs - here is a JPG example: the main header image on http://www.xjw.com/ .

Gerv

Comment 5

[Frank Wein [:mcsmurf]]

Just in case it might matter: What X server version do you use (and what Linux distribution)?

Comment 6

[Gervase Markham [:gerv]]

I use Ubuntu 6.06 LTS "Dapper Drake". I'm using the Xorg X server that comes with it.

gerv@shrew$ Xorg -version

X Window System Version 7.0.0
Release Date: 21 December 2005
X Protocol Version 11, Revision 0, Release 7.0
Build Operating System:Linux 2.6.12 i686
Current Operating System: Linux shrew 2.6.15-25-686 #1 SMP PREEMPT Wed Jun 14 11:34:19 UTC 2006 i686
Build Date: 16 March 2006

Gerv

Comment 7

[Takanori MATSUURA]

Similar bug is also reported at the Mozilla-gumi bugzilla.
http://bugzilla.mozilla.gr.jp/show_bug.cgi?id=5153
(Written in Japanese)

Test case is
http://bugzilla.mozilla.gr.jp/attachment.cgi?id=3178

When you change the image by clicking the link of "Basic", "Business", or "Classic", Image is broken.

In that bug, I reported that,
1. build locally from the latest trunk without cairo (--enable-default-toolkit=gtk2) is NOT affected with both "nv" (that is included in xorg-x11) and "nvidia" driver (that is available from nvidia.com).
2. latest trunk build binary from ftp.mozilla.org is affected if "nv" driver   is used and NOT affected if "nvidia" driver is used.

My test environment is Fedora Core 5.

So we guess that
1. cairo build requires more resources for displaying images
or
2. this is the bug of xorg-x11-7.0

Comment 8

[Takanori MATSUURA]

And another reporter who is using "i810" driver reported that this bug is not appeared by changing the depth value from 24 to 16.

Comment 9

[Gervase Markham [:gerv]]

I am using the "nv" driver. Changing from 24 to 16-bit colour in my X server (change "DefaultDepth" in xorg.conf; restart server using Ctrl-Alt-Backspace) makes the problem go away.

So this bug is shown when:
- displaying some but not all scaled images
- which can be at least any of PNG, JPG or GIF
- on cairo builds 
- at 24bpp colour depth
- using some but not all display drivers.

Gerv

Comment 10

[Gervase Markham [:gerv]]

I no longer see this bug with the testcases here under the same conditions using:
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9a1) Gecko/20061218 Minefield/3.0a1

I don't know what's up with the Gecko date; I downloaded it from the "latest" directory on the 5th Jan.

gerv@otter:Download$ Xorg -version

X Window System Version 7.1.1
Release Date: 12 May 2006
X Protocol Version 11, Revision 0, Release 7.1.1
Build Operating System: Linux 2.6.15.7 i686 
Current Operating System: Linux otter 2.6.17-10-386 #2 Tue Dec 5 22:26:18 UTC 2006 i686
Build Date: 07 July 2006
        Before reporting problems, check http://wiki.x.org
        to make sure that you have the latest version.
Module Loader present

Gerv

Comment 11

[:Gavin Sharp [email: [e-mail]]]

(In reply to comment #10)
> I don't know what's up with the Gecko date; I downloaded it from the "latest"
> directory on the 5th Jan.

You probably downloaded firefox-3.0a1.en-US.linux-i686.tar.bz2 instead of firefox-3.0a2pre.en-US.linux-i686.tar.bz2. The version number was increased, but the old files were not removed, so they remained in the -latest directory. I thought a bug had been filed about it already, but I can't seem to find it.

Comment 12

[chado]

I'm not sure, but looks depend on Xorg or individual video-driver 
versions rather than Minefield builds.

I tried 2006-07-01-08-04-trunk (since Gerv's info) 
on my single machine with i810 video chipset:
Fedora Core 6 with Xorg-7.1.1 looks working fine.
Fedora Core 5 with Xorg-7.0.0 and another distribution called 
Vine Linux 4.0 with Xorg-6.9.0 still show this problem.

note:
Sometimes, it does not reproduce this with attachment#229349 [details] here, 
while it does with testcase mentioned in Comment#7.  

Comment 13

[chado]

(In reply to comment #12)
> I tried 2006-07-01-08-04-trunk (since Gerv's info) 

oops, I mean 2007-01-08-04-trunk.

Comment 14

[Gervase Markham [:gerv]]

This WORKSFORME on Ubuntu 7.10 with Firefox 2 and 3.

Gerv

Comment 15

[Gervase Markham [:gerv]]

Resolving WFM based on comment 14.

Gerv