1445034 - http://gifpaint.com/ canvas disappears when scrolling upwards

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Markus Stange [:mstange]]

Steps to reproduce:
 1. Go to http://gifpaint.com/ and dismiss the message box.
 2. Scroll down.
 3. Scroll up.

When scrolling up, the white canvas area in the middle briefly becomes light gray.

Comment 1

[Darkspirit]

Attachment: 2018-03-13_20-51-49.mp4

> mozregression --launch 2018-03-12 --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/"

Debian Testing (KDE, Radeon RX480)
Does not happen at 100% zoom and not on every zoom level. Sometimes it's just a light-grey flickering while scrolling, sometimes just like seen in this screencast.

Comment 2

[Darkspirit]

> Sometimes it's just a light-grey flickering while scrolling, sometimes just like seen in this screencast.
flickering: at 140% zoom, untouched window height
static color change: with a smaller window height

------

at 140% zoom.
mozregression --good 2018-01-15 --bad 2018-03-12 --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/"
> 14:09.21 INFO: Last good revision: cfc5d19e856fc43766669069b7e2695dd519e5c3
> 14:09.21 INFO: First bad revision: 81f389c2524e58b4b95844667719cc1642573019
> 14:09.21 INFO: Pushlog:
> https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=cfc5d19e856fc43766669069b7e2695dd519e5c3&tochange=81f389c2524e58b4b95844667719cc1642573019

> 81f389c2524e	Kartikaya Gupta — Bug 1440664 - Update reftest annotation for changes in WR PR 2471. r=jrmuizel
> 507a25c3afd0	Kartikaya Gupta — Bug 1440664 - Update reftest annotation for WR PR 2443. r=jrmuizel
> 6098d2c015d7	Kartikaya Gupta — Bug 1440664 - Re-generate FFI header. r=jrmuizel
> a5991299ebd0	Kartikaya Gupta — Bug 1440664 - Update Cargo lockfiles and re-vendor rust dependencies. r=jrmuizel
> c066c419e378	Martin Robinson — Bug 1440664 - Update gecko WR bindings for API changes in WR PR 2449. r=kats
> 6f54af02c2e6	Kartikaya Gupta — Bug 1440664 - Update webrender to commit 22b831c02479eea31821f49a0fac7dd699083557. r=jrmuizel

try builds from bug 1440664:
> WR @ 992dbd3f07b143f35581012082aa59fbda7c387e
mozregression --repo try --launch 4916bd1bb3e9470ea106ebf45859b68b2a1b474c --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/"
bad

> WR @ 0b711f2e514107361deef4297c3c7da794d4835c
mozregression --repo try --launch 9cbf4580d196e5997b2ca7f8ce4fa26b49e47b0f --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/"
bad

Regression range: https://github.com/servo/webrender/compare/8a19316a733a484bf9bafb8257e3008b1418bfe4...992dbd3f07b143f35581012082aa59fbda7c387e

Comment 3

[Jeff Muizelaar [:jrmuizel]]

Nical, this looks like you.

Comment 4

[Markus Stange [:mstange]]

If this really is caused by the same bug as bug 1446129, then I suggest debugging the testcase in that bug instead of debugging gifpaint.com itself.

Comment 5

[Nicolas Silva [:nical]]

Fix in https://github.com/servo/webrender/pull/2568

Comment 6

[Darkspirit]

try build from bug 1447998 comment 4:
> WR @ 00b85801f8c09431e5963a9e1dcd1a9087b744b9
mozregression --repo try --launch 5f58a8fa82a9c7ed75867993058a03e3b2e58827 --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/|https://bug1446129.bmoattachments.org/attachment.cgi?id=8959296|http://localhost/background_broken.html"
* bug 1445034: bad
* bug 1446129: bad
* bug 1446626: bad

try build from bug 1447998 comment 5:
> WR @ 43c0cde08f71b800d45ad35119bd20b561288a34
mozregression --repo try --launch a92e61fbb71b3b6e9825e5bb15e58fd9887fb40f --pref gfx.webrender.all:true startup.homepage_welcome_url:"http://gifpaint.com/|https://bug1446129.bmoattachments.org/attachment.cgi?id=8959296|http://localhost/background_broken.html"
* bug 1445034: fixed
* bug 1446129: fixed
* bug 1446626: still bad

Comment 8

[Nicolas Silva [:nical]]

Looks like this was fixed in https://github.com/servo/webrender/pull/2568.