When there are multiple overlays, wr_renderer_readback() could not be used for taking snapshot. It is nice if PrintWindow() could be used for taking snapshots.

It seems that we could take a snapshot of multiple DirectComposition overlays when we use PrintWindow() with PW_RENDERFULLCONTENT flag.

In the past, when I tested it without os compositor on try server, sometimes it failed to take a screenshot. It is necessary to retest with os compositor.

The patch was affected by Bug 1591346. BITMAPV4HEADER needs to be changed to top-to-buttom DIB.

(In reply to Sotaro Ikeda [:sotaro] from comment #3)

The patch was affected by Bug 1591346. BITMAPV4HEADER needs to be changed to top-to-buttom DIB.

Updated a patch.

There were test failures. When it happened, it seemed that it failed to get a screenshot.
https://treeherder.mozilla.org/#/jobs?repo=try&revision=4ff279ed422c09586724d6c8019e7ad7a75a1ca6

Waiting gpu tasks complete reduced the intermittent failures, though they still exists.
https://treeherder.mozilla.org/#/jobs?repo=try&revision=2ea5000878bd78ba96aae63ebd8f745582014cf4

Even though, there is enough wait, there is still a case that we could not get correct screenshot :(
https://treeherder.mozilla.org/#/jobs?repo=try&revision=6cfb00aa86de7ff942b3e266015abb07e123fa08

:gw, do you have an idea how to address the reftest? PrintWindow() is a windows api, we do not know an internal of it. Then it might be better not to use PrintWindow() for taking screenshot.

I'll investigate this today.

Thank you!

In the attached patch, the implementation of DCLayerTree::WaitForCommitCompletion calls the wrong method.

I kicked off a try run with that updated to call WaitForCommitCompletion on the DC device (patch applied on top of your existing patch).

https://hg.mozilla.org/try/rev/8bccbb22c5eee759f86c97c820864602d5160705
https://treeherder.mozilla.org/#/jobs?repo=try&revision=8bccbb22c5eee759f86c97c820864602d5160705

The try run with that change seems good.

It seems that we could remove ID3D11Query wait during taking a snapshot.
https://treeherder.mozilla.org/#/jobs?repo=try&selectedJob=278722119&revision=9c2485d06c75d75a36ca32eac69421145b4a6339

https://hg.mozilla.org/mozilla-central/rev/dab4de5a90b9

It seems that recent change caused reftest failure though PrintWindow() seemed to work.
https://treeherder.mozilla.org/#/jobs?repo=try&author=sikeda.birchill%40mozilla.com&selectedJob=279253707

(In reply to Sotaro Ikeda [:sotaro] from comment #16)

It seems that recent change caused reftest failure though PrintWindow() seemed to work.
https://treeherder.mozilla.org/#/jobs?repo=try&author=sikeda.birchill%40mozilla.com&selectedJob=279253707

It seems to be addressed on latest m-c

• https://treeherder.mozilla.org/#/jobs?repo=try&revision=3a5cea30145a9b720fa2b20352d999e97e610651