Bug 42300

Summary:

Canvas: Don't add shadow rect to dirty region when shadow alpha is 0

Product:

WebKit

Reporter:

Andreas Kling <kling>

Component:

WebCore Misc.

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

oliver

Priority:

Keywords:

Performance

Version:

528+ (Nightly build)

Hardware:

All

OS:

All

Attachments:

Description	Flags
Proposed patch	none

Description Andreas Kling 2010-07-14 16:05:04 PDT

CanvasRenderingContext2D::willDraw() will always add the current shadow rect to the dirty region.
We can skip this if the current shadow color has a zero alpha value.

Comment 1 Andreas Kling 2010-07-14 16:06:14 PDT

Created attachment 61578 [details]
Proposed patch

Comment 2 Darin Adler 2010-07-14 16:14:27 PDT

Comment on attachment 61578 [details]
Proposed patch

It’s unfortunate we have to construct a Color just to check the alpha channel. That’s going to cost some actual instructions and CPU time. Maybe we should have more functions that operate directly on RGBA32 values.

Comment 3 Andreas Kling 2010-07-14 16:25:22 PDT

(In reply to comment #2)
> (From update of attachment 61578 [details])
> It’s unfortunate we have to construct a Color just to check the alpha channel. That’s going to cost some actual instructions and CPU time. Maybe we should have more functions that operate directly on RGBA32 values.

Agreed. Coming soon in a separate patch.

Comment 4 Andreas Kling 2010-07-14 16:28:06 PDT

Comment on attachment 61578 [details]
Proposed patch

Clearing flags on attachment: 61578

Committed r63370: <http://trac.webkit.org/changeset/63370>

Comment 5 Andreas Kling 2010-07-14 16:28:16 PDT

All reviewed patches have been landed.  Closing bug.