Bug 74786 – Do accelerated filtering when drop-shadow is not the last filter in the chain

• Status: NEW
• Component: Layout and Rendering

[Chris Marrin]

With https://bugs.webkit.org/show_bug.cgi?id=68479 filters are accelerated on CALayers. But the drop-shadow filter is done with CA's shadow properties which are applied after filters. So currently drop-shadow has to be the last filter in the chain or we don't accelerate filters. We could add a parent layer which could render all the filters that come after the drop-shadow.

[Chris Marrin]

Add webkit-bug-importer to CC list

[Adam Roben (:aroben)]

(Pinging bug importer)

[Radar WebKit Bug Importer]

<rdar://problem/10601044>

[Dirk Schulze]

I might be wrong, but if I understand the code correctly, each filter is added to a filter chain "array". Would it be much slower to replace a drop shadow with
* a blur filter
* 2 compositing filter (one compositing with a flood color)
* 1 affineTransform filter

I just looked at the CIFilter path, but it doesn't look so much different to CAFilter, does it? I couldn't find official docs for CAFilter.

[Dean Jackson]

(In reply to comment #4)
> I might be wrong, but if I understand the code correctly, each filter is added to a filter chain "array". Would it be much slower to replace a drop shadow with
> * a blur filter
> * 2 compositing filter (one compositing with a flood color)
> * 1 affineTransform filter
> 
> I just looked at the CIFilter path, but it doesn't look so much different to CAFilter, does it? I couldn't find official docs for CAFilter.

We could do this with CI but not CA filters (because they don't have a blend that takes two inputs).