131866 - renders incorrectly when scrolling

Status: RESOLVED DUPLICATE of bug 121230

(Core :: Graphics: ImageLib, defect)

Description

[Steve Hugg]

From Bugzilla Helper:
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:0.9.9) Gecko/20020311
BuildID:    2002031104

The PNG test page (Debug | Verification | PNG Images) displays correctly on page
load and redraw, but does not when scrolling.  It looks like it is being
rendered upside down when partial updates are done -- if you scroll very slowly
past the picture, it reappears upside down (but with minor artifacts).

Reproducible: Always
Steps to Reproduce:
1. Go to http://www.libpng.org/pub/png/png-MagnoliaAlpha.html
2. Scroll the picture off the screen
3. Scroll the picture back on the screen using scroll bar or arrow keys.

Actual Results:  Upside down and artifact-y picture.

Expected Results:  Displayed picture correctly.

Comment 1

[Boris Zbarsky [:bzbarsky]]

imagelib

Comment 2

[Kris]

Attachment: Scroll all the way to the bottom, then scroll back up slowly

This is the "result" with this bug. I believe it is related to a similar
rendering problem with 116593.

It's definitely a problem with how the display is being repainted while
scrolling.

Window has to be either resized, reloaded or another window dragged overtop of
it to show a correct result.

Comment 3

[R.K.Aa.]

*** This bug has been marked as a duplicate of 121230 ***