1388235 - Support fallback path for nsDisplayFilter.

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, enhancement)

Description

[Morris Tseng [:mtseng] [:Morris] (Inactive)]

In bug 1386188, we add support for nsDisplayFilter. Since webrender doesn't support all filter effects, we need some fallback mechanism for unsupport effects. Because nsDisplayFilter is container type displayitem and fallback for container type displayitem is not trivial. Per discussion with Ethan, we have following proposals:

1. Reuse FrameLayerBuilder and BasicLayerManager.
This might be simplest solution.

2. Implement a custom fallback mechanism for layers-free mode.
This has some problem because nsDisplayFilter is a container type display item which means it would container all kind of display item in it. So we need implement a general fallback mechanism for all display item types.

3. Record filter's moz2d command and replay it on webrender.
We don't know this is doable or not. But just like blob image, we record commands and send it to webrender. Webrender readback the buffer which need apply filter then replay the commands on this buffer.

4. Fully support css/svg filter in webrender
Once this is done, we don't need fallback path for filter.

Kats, Jeff, Do you have any suggestions for above proposals?

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I don't really have any suggestions. I think long-term we want to go with (4), correct? If that's the case and that's hard to do in the short-term then I think (1) might be the best way to go as it's simple. But I don't really know.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Thoughts:
1. Reuse FrameLayerBuilder and BasicLayerManager.
- This isn't my favourite but indeed probably the quickest way to a correct solution. I think it's probably worth pursuing this first to see if it can easily become workable.

2. I think this could be workable, but it's harder to know how much work it will be. I think this could end up better and simpler than 1. We should still probably try 1 first though.

3. I don't really want to try this.

4. This would of course be best, but I like the comfort of being able to fallback to something we know works.

In summary: I think we should go for 1. to start. Let's see how it turns out and then evaluate whether it makes sense.

Comment 3

[Markus Stange [:mstange]]

I agree with Jeff's assessment.

Comment 4

[Morris Tseng [:mtseng] [:Morris] (Inactive)]

Attachment: Bug 1388235 - Support fallback path for nsDisplayFilter.

Use FrameLayerBuilder and BasicLayerManager for rendering filter effects
that webrender not supported.

Review commit: https://reviewboard.mozilla.org/r/168966/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/168966/

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Comment on attachment 8897689 [details]
Bug 1388235 - Support fallback path for nsDisplayFilter.

https://reviewboard.mozilla.org/r/168966/#review174906

Comment 6

[Morris Tseng [:mtseng] [:Morris] (Inactive)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=f79c7662126a7cbf406bb205d31cc2c7ba77c852

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/ee2d23448326
Support fallback path for nsDisplayFilter. r=jrmuizel

Comment 8

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

https://hg.mozilla.org/mozilla-central/rev/ee2d23448326