94494 - GIFs get scrambled when scrolled off the screen

Status: RESOLVED DUPLICATE of bug 104992

(Core :: Graphics: ImageLib, defect)

Description

[bugzilla]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:0.9.3) Gecko/20010801
BuildID:    2001080110

Initial rendering of GIFs works fine.
But when the page is scrolled the gifs get scrambled
when they are scrolled back into view.  Does not
happen with all images.  Suspect that transparent
background is involved.  Have seen the same problem
on  www.cnn.com and other sites.

Reproducible: Always
Steps to Reproduce:
1.load http://www.cheesemaking.com/
2.scroll window down so that buttons on left disapper
3.scroll window up to show buttons again

Comment 1

[Matthias Versen [:Matti]]

wfm with win2k build 20010809..

->imagelib

Comment 2

[gavin long]

WFM, Win98SE, 20010080703

Comment 3

[Grey Hodge (jX)]

*** Bug 94838 has been marked as a duplicate of this bug. ***

Comment 4

[Alfonso Martinez]

WFM win98, build 2001081303

Comment 5

[gavin long]

Confirming, this already has one dupe, and I've seen this mentioned twice more.
 Quite a few people are seeing this, even if I'm not.

bug 94818 describes two issues, one of which sounds just like this.  94818, the
existing dupe (bug 94838) and this bug are all 0.9.3 on Win98.

bug 96043 again describes 2 issues, one of which sounds like this (N.B. this was
reported on OS/2)

Comment 6

[Terri Preston]

Hmm, this works for me on win98 build 2001110603, Win XP 2001103103 and mac OS X 
2001110605 so I'm marking WFM, reporter, please feel free to reopen 

Comment 7

[Patrick]

build 2001 11 09 03
I just tried it out and it doesn't seem fixed for me even though I hadn't seen
it for a while with a preceeding build. We might have fixed it and then
regressed. Could you please reopen this bug to foolow its evolution? Thank you!

Comment 8

[Patrick]

Attachment: screenshot

This is a screenshot to show the problem. Window is small just to make the
image smaller.

Comment 9

[Christian :Biesinger (don't email me, ping me on IRC)]

Reopening per Patrick's comment

Comment 10

[Patrick]

OK, still confirmed with today's build: 2001 11 26 03.

I remarked sth interesting though when testing it on
http://www.tomshardware.com/: when the window is maximized, the issue doesn't
occur when scrolling up but when scrolling down only. When the window is smaller
(the size seem to matter rather than the maximized/restored status) it occurs in
both directions.

Comment 11

[Patrick]

One useful thing I remarked is that the scrambled image gets fixed when you
click on it. If someone has an idea of what occurs when you click on an image,
we might be close to the solution.

Also, clicking on the image brings a new item in the page contextual menu:
"search for '[xyz]'". Displayed without the double quotes and where xyz is the
content of the alt value of the img tag.

Something else is that sometimes the problem is not present at all in a complete
session of Mozilla and at other times, it's present in all the windows.

Comment 12

[Daniel Steinberger]

well, this WFM in my build. but i found a similar problem on a page i wrote for
fun. on the bottom there's a w3.org valid HTML image. this one get smashed, too
if one scroles the right way. my build is 2002020103. the url is
http://buerger.metropolis.de/storesomestuff/ and the way to reproduce it is:
1. go to above url
2. scroll down by grabbing the scrollbar(!) and scrolling down *gently* and
*slowly*.
the image should be scrambled now in a funny way. you can make the error go away
by putting _any_ window in front of it and then removing it again. this only
appears when scrolling.

Comment 13

[Tim Powell]

I don't know if this has the same cause, but I'm seeing a similar problem with
PNG images on http://www.mozillanews.org Dragging the scrollbar thumb and
scrolling slowly downward and then back up causes image corruption with the
2002020208 build on Win2K. 

I see it most with this image:
http://www.mozillanews.org/images/icons/development.png

Should I log this as a new bug?

Comment 14

[Terri Preston]

Thanks Tim Powell, I can reproduce with your URL, marking nsbeta1

Comment 15

[Daniel Steinberger]

hm, i already filed a bug about those problems with PNGs - initially i thought
this had another cause, but further investigation lead to me seeing this on more
examples, like the w3 valid banners - my bug is bug 121230
terri: maybe you should take a look there, too. as i said i first thought, it
was another cause, but then i investigated the problem and saw, it wasn't a
problem with layout, but imagelib. so, i suggested to change component, but so
far noone answerd my call. please take a look there, since it has a good
summary, i think.

Comment 16

[Ian Westcott]

I reported this not long ago as bug 121778.  Other closely related reports are
bug 96803 and bug 83289 comment 115.  All of these reports (and my personal
experience) indicate that the problem lies with transparent images that have
transparency on all four sides, and that it occurrs with both GIF and PNG
images.  I have noticed that some people report seeing the problem, but many
others don't, so could it have something to do with video card drivers, or some
other user-specific thing? (I doubt this, but it never hurts to ask)

There are also a number of bugs discussing problems with GIF images as
backgrounds.  I have yet to research their relevance, but the two issues might
be related somehow.

I created a screenshot example to go with my report at:
http://www.ianw.org/misc/bug121778.html 

Should bug 121778 and bug 96803 be marked as dupes?  please confirm. 

Comment 17

[Gagan]

per adt, critical for nsbeta1. hence plus.

Comment 18

[Tim Powell]

*** Bug 121778 has been marked as a duplicate of this bug. ***

Comment 19

[selmer (gone)]

I see this on my win98 system using build 4/9 03 with an email that has gifs in
it.  The same email works fine on NT with the same build.  In this email,
backgrounds do appear to be involved since the bg is white when it draws
correctly and black when munged by scrolling.  

Clicking on the images in the email didn't do anything, but resizing the window
causes a refresh that clears up the scrambling.  Your click probably caused a
refresh somehow.

Comment 20

[Kevin Gadd]

This happens with PNGs too, at least on my ATI Radeon 8500 with Build 2002031104
on WinXP.

Comment 21

[scottputterman]

Changing nsbeta1+ [adt3] bugs to nsbeta1- on behalf of the adt.  If you have any
questions about this, please email [e-mail].  You can search for
"changing adt3 bugs" to quickly find and delete these bug mails.

Comment 22

[scottputterman]

Changing nsbeta1+ [adt3] bugs to nsbeta1- on behalf of the adt.  If you have any
questions about this, please email [e-mail].  You can search for
"changing adt3 bugs" to quickly find and delete these bug mails.

Comment 23

[Masayuki Nakano [:masayuki] (he/him)(JST, +0900)]

I can't reproduce with 2002081604-trunk/WinXP.
WFM?

Comment 24

[Patrick]

Isn't this specific to some graphical card? ATI?

Comment 25

[Fabian]

I saw this bug today for the first time (1.3b, Build 2003021008, Win98SE) - any
GIF-Image was scrambled after scrolling. Maybe it IS a problem with Ati cards,
it never occurred on one of my Nvidia cards.
Two things helped. When I changed the display from 32bit to 24bit, everything
was fine with the Ati Driver "RAGE PRO TURBO AGP 2X", 9-14-1998. When I changed
to the Microsoft driver "ATI 3D Rage Pro", 5-5-1999, 32bit worked perfectly.
I' say it's not a Mozilla bug - except for the fact I never had any similar
problem with other software. Did anyone ask Ati about it?

Comment 26

[Andrew Hagen]

Workarounds are available. Duping to higher number bug because it has more
information.

*** This bug has been marked as a duplicate of 104992 ***