1804746 - canvas.toBlob() does not work on transferred offscreen canvas

Status: VERIFIED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Corvyn Kusuma]

Attachment: manual-worker-capture-canvas.zip

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Steps to reproduce:

• Unzip manual-worker-capture-canvas.zip and start a server on the folder
• Open "test.html"
• Click on "Capture Canvas To Image" button

Actual results:

The image capture of the canvas when the button is pressed is blank.

Expected results:

A properly filled image capture of the canvas should be displayed below the canvas. The expected behavior works on Chrome (tested in 108.0.5359.94).

Comment 1

[Corvyn Kusuma]

Auxillary bug: right when the test video loops, an exception is thrown from createImageBitmap() which is caught from the catch:

"DOMException: An attempt was made to use an object that is not, or is no longer, usable"

Chrome 108 also does not have this error thrown.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Graphics: Canvas2D' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 3

[Corvyn Kusuma]

Friendly bump on this issue

Comment 4

[Kelsey Gilbert [:jgilbert]]

@aosmond: Is this expected to be unimplemented?

Comment 5

[Andrew Osmond [:aosmond] (he/him)]

Adjusting the test case to work with ToDataURL works with my patch in bug 1744854 (and in Chrome), so I just need to land that and do something similar for ToBlob.

Comment 6

[Andrew Osmond [:aosmond] (he/him)]

Attachment: Bug 1804746 - Make HTMLCanvasElement's toBlob to work with OffscreenCanvas.

Depends on D130788

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5d1a79d9c33a
Make HTMLCanvasElement's toBlob to work with OffscreenCanvas. r=gfx-reviewers,lsalzman

Comment 8

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/5d1a79d9c33a

Comment 9

[Anca Soncutean, Desktop QA]

Reproduced with Fx 109.0a1(2022-12-08) on macOS 13.
Verified fixed with FX 120.0a1(2023-10-01) and Fx 119.0b3 on macOS 13.