1741314 - Text in google docs gradually gets darker and darker with experimental WebGL canvas

Status: VERIFIED FIXED

(Core :: Graphics, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

Just noticed this today.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Attachment: Before

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Attachment: Screen Shot 2021-11-15 at 8.22.04 PM.png

I can reproduce this by switching to the tab and then repeatedly selecting and unselecting the text underneath it.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

This only seems to happen if you end up with the canvas renderer.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

Ah turns out this was caused by gfx.canvas.accelerated=true

Comment 5

[Lee Salzman [:lsalzman]]

Attachment: Bug 1741314 - Use OP_SOURCE in DrawTargetWebgl::FlushFromSkia. r?jrmuizel

I was accidentally using OP_OVER when trying to flush the Skia target to the WebGL context.
This meant any alpha values caused blending with the previous WebGL context contents, rather
than overwriting them entirely which was the actually desired effect.

Incidental finding while debugging this is that we also need to handle empty rects better by
just ignoring them.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/84ef54ebd02c
Use OP_SOURCE in DrawTargetWebgl::FlushFromSkia. r=jrmuizel

Comment 7

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/84ef54ebd02c

Comment 8

[Monica Chiorean]

I tried to reproduce the issue on Win10x64 using build 96.0a1 (20211115215316) and setting 'gfx.canvas.accelerated=true', but text in my google document did not get any darker even after switching tabs.
Can you please add OS used?
Is the issue still reproducing for you on latest RC? (Fx96.0) build(https://archive.mozilla.org/pub/firefox/candidates/96.0b9-candidates/build1/win64/en-US/) ?
Thank you.

Comment 9

[Jeff Muizelaar [:jrmuizel]]

This was fixed.

Comment 10

[Monica Chiorean]

Closing based on comment#9.