752959 - Margins of page flicker when zooming out

Status: RESOLVED WORKSFORME

(Firefox for Android Graveyard :: Toolbar, defect)

Description

[Irina Sandu]

Attachment: picture of problem

When I zoom out more than the limit of the page and pan around the web page, the margins of the page flicker. See picture.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

What device and build were you using? Does it happen only on specific pages, or any page?

Comment 2

[Irina Sandu]

The build is the latest nightly and device is Galaxy Nexus, ICS. It happens on all pages, but on one with just an image, like the one in the picture, the margin that flickers black - white is thicker. Also it happens on the right-hand side and bottom margins, not the other 2.

Comment 3

[Irina Sandu]

It happens on images from imgur, such as i.imgur.com/ExZly.png

Comment 4

[Irina Sandu]

The link in comment 3 I see doesn't work anymore, but this one does (and I can reproduce): http://i.imgur.com/ShiMo.png

Comment 5

[Kartikaya Gupta (email:[e-mail])]

I'm able to see flickering but only 1-pixel wide. It seems like a rounding error to me. I haven't seen the wider flickering area mentioned in comment 2.

Comment 7

[Kartikaya Gupta (email:[e-mail])]

I don't think this is the same issue as bug 749731. That one happens in the middle of pages as you scroll. This one only happens on the right/bottom edges of the page and is likely because two of gecko/compositor/java are rounding things differently.

Comment 8

[Kartikaya Gupta (email:[e-mail])]

I looked at this further using a simplified test case at http://people.mozilla.org/~kgupta/bug/752959.html - pinching and panning there shows the same small flicker around the edges. The yellow back is getting painted by drawBackground in LayerRenderer.java, and it's clearly using a different rounding scheme than what the compositor is using. This will need to be addressed, but I'm going to wait until my patches from bug 748384 are in, because they propagate a lot of changes everywhere (also this bug is not a blocker so it can wait for now).

Comment 9

[Brad Lassey [:blassey] (use needinfo?)]

qawanted to retest

Comment 10

[Kartikaya Gupta (email:[e-mail])]

I just saw this the other day; it's still reproducible on my test case in comment #8.

Comment 11

[Brad Lassey [:blassey] (use needinfo?)]

Kats, do you have a plan for this? Is it reasonable to still track this for 19?

Comment 12

[Kartikaya Gupta (email:[e-mail])]

I have an outline of a plan but it will be too risky to take in 19, even assuming it gets done in 20, which it probably won't.

Comment 13

[Kartikaya Gupta (email:[e-mail])]

We don't support zooming out into overscroll anymore, so this is WFM.