762973 - All Canvas2d globalCompositeOperations except "source-over" are very slow

Status: NEW

(Core :: Graphics: Canvas2D, defect)

Description

[Glenn Barnett]

Attachment: Image of jsperf browser comparison chart (FF12 vs FF11 etc)

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.19 (KHTML, like Gecko) Chrome/18.0.1025.168 Safari/535.19

Steps to reproduce:

Went to http://jsperf.com/canvas-global-composite-operations


Actual results:

The "source-atop" test achieved over 248,000 ops/sec.

Every other global composite operation achieved under 2,000 ops/sec



Expected results:

The other GCO's should have achieved higher than 2,000; in Firefox 11, they most achieved in the 60,000 range (see attached graph)

This issue affects FF 12 and FF 13

Comment 1

[Glenn Barnett]

Oops, I said "source-atop", but meant "source-over"

"source-over" is the default, and the one that's really fast.

Comment 2

[Katelyn Gadd (:kael)]

I use "lighter" extensively because it's the only remotely efficient way to approximate the GL_MULTIPLY blend equation in canvas. IIRC based on discussions with the GFX guys this problem is caused by Direct2D not exposing any control over blend operations, so any non-source-atop blend operation requires an expensive Direct3D fallback.

Comment 3

[Katelyn Gadd (:kael)]

For a real-world example, the level editor in http://playescapegoat.com/ gets absolutely murdered by this. Even caching the rendered output isn't enough.

Comment 4

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

Note: This is still slow with Firefox 23 + Direct2D/Azure canvas.

Comment 5

[bernhard.robert.pichler]

Note also: CompositeOperations like "lighter" works pretty fast in other browsers like Chrome. It would be a nice feature for particle effects.

Comment 6

[Daniel Szabo]

This is still an issue.
I've checked the original test case at http://jsperf.com/canvas-global-composite-operations

Current beta (38.0.5) renders all composition modes other than "source-over" at 4% of the speed of "source-over".

In contrast, Chrome 42 renders at 40%-70% of the speed of "source-over" (which is 10% faster than Firefox on same PC anyway).

Thus, Chrome renders upto 10-20 times faster.