1293968 - Avoid calling EnsureTarget in CanvasRenderingContext2D::GetImageBuffer

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Nicolas Silva [:nical]]

GetImageBuffer needs to access a snapshot of the canvas without retaining it, we could easily avoid calling EnsureTarget in most case by doing something like:


if (mTarget) {
  snapshot = mTargetSnapshot()
} else if (mBufferProvider) {
  snapshot = mBufferProvider->BorrowSnapshot();
} else {
  //fallback to EnsureTarget, should rarely happen though.
}
// .. do things with the snapshot

if (!mTarget && mBufferProvider) {
  mBufferProvider->ReturnSnapsht(snapshot.forget());
}

This way we can avoid triggering a copy of the canvas if the first command issued to the canvas in a frame is a snapshot.

Comment 1

[Ethan Lin[:ethlin]]

I'll work on this too.

Comment 2

[Ethan Lin[:ethlin]]

Attachment: avoid calling EnsureTarget

Try to avoid calling EnsureTarget in GetImageBuffer.

Comment 3

[Ethan Lin[:ethlin]]

try server:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=e49512f5c066

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/6a868ef45569
Avoid calling EnsureTarget in CanvasRenderingContext2D::GetImageBuffer. r=nical

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/6a868ef45569