1435546 - Drawing to one canvas on a page affects another canvas

Status: RESOLVED DUPLICATE of bug 1436466

(Core :: Canvas: 2D, defect, P1)

Description

[Ori Avtalion (salty-horse)]

Attachment: Test-case

Tested with Firefox for Android Beta and Nightly, on Nexus 5X.

The attached test-case has two canvases.
In one is drawn a red box, in the other a green box.
They also have colored borders that match the colors of the drawn boxes.

There are two bugs here:

1) When Firefox "loses focus" (for example when switching to another app, or locking the screen), when it regains focus the two canvases will be empty.

2) I have rigged a redraw of the red canvas when the page is clicked. Such a redraw after step #1 will cause both canvases to be red, as if they're sharing a context.

#1 only seems to happen when the canvases are large. Are they unloaded from memory?

Comment 1

[Jan Henning [:JanH]]

I can't reproduce #2 on my phone, but #1 seems like a regression from bug 1379920.

Comment 2

[Jan Henning [:JanH]]

Additionally, when I try to bring Firefox back into the foreground on a debug build, I get the following assertion:
> 02-06 21:08:30.568 7799-7863/org.mozilla.fennec_jan A/MOZ_Assert: Assertion failure: status != 0 (ClientWaitSync generated an error. Has mSync already been destroyed?), at /home/jan/Mozilla/mozilla-central/gfx/layers/opengl/TextureHostOGL.cpp:687

And the thing that triggers this seems to be the heap minimisation we do when going into the background on Android. If I comment out this line (https://dxr.mozilla.org/mozilla-central/rev/0d806b3230fe4767fa70cdee57db87d1e9a5ba49/widget/android/nsAppShell.cpp#184), I can no longer reproduce this on a local build.

Comment 3

[Milan Sreckovic [:milan] (needinfo for best results)]

Jamie, can you reproduce on any of the phones you have?

Comment 4

[Ori Avtalion (salty-horse)]

I tested this on another phone, Xiaomi Mi 5, and only #1 happens.
When it tries to draw the red square, it appears in just one canvas.

Comment 5

[Jan Henning [:JanH]]

Moving issue #1 over to bug 1436466 to keep things separate.

Comment 6

[Ori Avtalion (salty-horse)]

Tested on Nexus 5 and Pixel 2 phones. Only #1 happens.

Comment 7

[Ori Avtalion (salty-horse)]

With bug 1436466 fixed, I can no longer reproduce this.
Should this bug be closed, or is there a worry of a different way it can be exposed?

Comment 8

[Sotaro Ikeda [:sotaro]]

This bug could be closed.