1145278 - Visible image glitches when scrolling http://www.google.com/makani the first time

Status: RESOLVED DUPLICATE of bug 1144899

(Core :: Graphics: ImageLib, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 1. Visit http://www.google.com/makani
    (Shift+Reload if you've visited it before)

 2. Hit spacebar or downarrow, to scroll to the next section. (and the next, and the next.)

ACTUAL RESULTS:
As sections scroll in, there are visible glitches with the scrolled-in background image (possibly from lazy decoding?).

EXPECTED RESULTS:
No such glitches.


NOTE: This only reproduces the first time I scroll through the page. If I reload (without shift), or if I scroll back to the top (w/ mouse-scrollwheel) and then scroll down again, I don't hit the bug.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: screencast

Comment 2

[Daniel Holbert [:dholbert]]

Version info: Nightly 39.0a1 (2015-03-19)
Mozilla/5.0 (X11; Linux x86_64; rv:39.0) Gecko/20100101 Firefox/39.0

(It's possible this is a layers bug or a layout/animation bug, too. But I'm guessing, imagelib given that it's fixed after a reload, if you've scrolled through all the content -- and you can only re-break it by shift-reloading [forcing you to redownload/redecode images].)

Comment 3

[Daniel Holbert [:dholbert]]

Looks like this was a new regression in yesterday's nightly, actually. Likely a regression from bug 1124084 (which enabled the downscale-during-decode pref).

Possibly a dupe of bug 1144899.

Comment 4

[Daniel Holbert [:dholbert]]

Yup, I confirmed locally that (1) I can reproduce this in a debug build, and (2) bug 1144899's patch fixes it.

--> Duping to bug 1144899.

Comment 5

[Daniel Holbert [:dholbert]]

Attachment: screencast 2 (larger window)

Here's another screencast where the bug may be more obvious. In this one, I scroll through the page twice. The first time reproduces the bug; the second time does not. (since at that point, everything's decoded)