86695 - Occasional scrolling 'artifacts'

Status: RESOLVED DUPLICATE of bug 83289

(Core Graveyard :: GFX, defect)

Description

[Rob Yampolsky]

This is purely cosmetic, and I would assume it's been reported before.  But I
can't find this problem in Bugzilla, and it's been around for so long, that it
really ought to get fixed one of these days.

Basically, when you scroll the window, you occasionally get a line of text
distorted.  I think this has to do with a 1-pixel error in defining the
scrolling region.  Either a pixel from the edge of the window is being scrolled
along with the window contents, or one too few pixels are getting scrolled.  Or
something like that.

Visual effect is that a row of text is either 'squashed' looking (missing scan
line?) or 'stretched' vertically (doubled scann line?).  I've also seen cases
where a fine horizontal line appears in the middle of the page.

All of these 'artifacts' disappear if you scroll them off of the window and back on.

Couldn't get this to happen with NS6.1 pre-release, but it still happens with
Mozilla nightly 2001061504.

Comment 1

[Aaron Kaluszka]

I haven't seen it happen in Win2K, but I have in WinXP.

Comment 2

[Asa Dotzler [:asa]]

reassign.

Comment 3

[Chris Petersen]

Reporter, can you try to reproduce this in a newer build. If you can, please
attach a screen shot if possible. 

Comment 4

[Matthew T (active 1999-2002)]

I see this semi-regularly on Mac OS; I'll attach a screenshot when it next happens.

This might be the same bug as bug 86834.

Comment 5

[Francisco León]

Been trying to find this one a long time ago
I can attach a screenshot. 

Comment 6

[Francisco León]

Attachment: After slowly scrolling an image

Comment 7

[Francisco León]

Just go to kernel.org and find that image to reproduce it
If you scroll too fast, you wont see it
The slower you scroll, the more lines you will see. My attachment shows the
problem as hard as it can be reproduced
I see this on linux, on any build
-> nsCatFood (this is probably my top visual bug in mozilla)

Comment 8

[Matthew T (active 1999-2002)]

*** Bug 92669 has been marked as a duplicate of this bug. ***

Comment 9

[Matthew T (active 1999-2002)]

I *thought* I'd seen this bug once too often ...

*** This bug has been marked as a duplicate of 83289 ***

Comment 10

[Alex Stewart]

Hmmm...the reporter was talking about _text_ being distorted....more like bug
66573 - Weird single pixel offsets in various parts of the page, but the
screenshots shown there show the text off by one wrt the left or right.