1296461 - Optimize imgFrames to RGBX off-main-thread

Status: RESOLVED INVALID

(Core :: Graphics: ImageLib, defect)

Description

[Seth Fowler [:seth] [:s2h]]

imgFrame can convert a surface that was initialized as RGBA to RGBX if we determine that it actually has no transparent pixels. This doesn't involve changing any of the image data; we just recreate the wrapping DataSourceSurface with a different format. In bug 1070426, we deferred making this change until imgFrame::Optimize() gets called because of concerns about changing |mImageSurface| while other code may be accessing the imgFrame concurrently. Since that time, doing this has become a lot safer. imgFrame has become a thread safe data structure, and we make the decision about whether an imgFrame has no transparent pixels only in imgFrame::Finish(), rather than at any arbitrary time that a decoder decides to call imgFrame::SetHasNoAlpha(), as was the case back in bug 1070426. Because of those changes, we can now perform this optimization off-main-thread, without waiting for imgFrame::Optimize() to run on the main thread. Let's do it.

Comment 1

[Seth Fowler [:seth] [:s2h]]

Attachment: Optimize imgFrames to RGBX off-main-thread.

Here's the patch. Since |mImageSurface| is protected by the monitor, there's no
danger in replacing it in imgFrame::Finish(). The only oddity this could create
is that we might have multiple SourceSurfaces for the same imgFrame if somebody
called imgFrame::GetSourceSurface() before imgFrame::Finish() got called, but
this can happen anyway, since in the (common) case where we get rid of
|mImageSurface| in imgFrame::Optimize(), imgFrame::GetSourceSurface() will
return a new SourceSurface every time it's called.

Comment 2

[Seth Fowler [:seth] [:s2h]]

Try job here:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=ebda62daa80d

Comment 3

[Seth Fowler [:seth] [:s2h]]

A second try job, because we need one that runs on Windows (aka, non-Skia) as well:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=1f47a12f9a5d

Comment 4

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

The bug assignee didn't login in Bugzilla in the last 7 months.
:aosmond, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 5

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

This is no longer relevant.