Fix for issue 1728: raster vs. gpu text draws with the wrong color

Fix for issue 1728: raster vs. gpu text draws with the wrong color

The blend mode for LCD text was not set up correctly when using colors with alpha. This takes the color's alpha value
into account when setting up the blending function.

BUG=Skia:1728
Committed: http://code.google.com/p/skia/source/detail?r=11980

[jvanverth1, 2013-10-25 21:27:50]

Replaced the two-pass method with the unpremultiplied color, single pass method
we talked about.

[bsalomon, 2013-10-28 13:12:21]

https://codereview.chromium.org/45363002/diff/50005/include/gpu/GrBitmapTextC...
File include/gpu/GrBitmapTextContext.h (right):

https://codereview.chromium.org/45363002/diff/50005/include/gpu/GrBitmapTextC...
include/gpu/GrBitmapTextContext.h:20: GrBitmapTextContext(GrContext*, const
GrPaint&, GrColor);
Since everywhere else GrColor is a premul color, maybe we should pass as SkColor
and convert in the text context? I'm concerned about opening the door to non-PM
GrColors in public APIs as it could get confusing.

https://codereview.chromium.org/45363002/diff/50005/src/gpu/GrBitmapTextConte...
File src/gpu/GrBitmapTextContext.cpp (right):

https://codereview.chromium.org/45363002/diff/50005/src/gpu/GrBitmapTextConte...
src/gpu/GrBitmapTextContext.cpp:66: bool lcdAlpha = false;
this and the below code guarded by this var don't appear to be used anymore.

[jvanverth1, 2013-10-28 14:00:52]

https://codereview.chromium.org/45363002/diff/50005/include/gpu/GrBitmapTextC...
File include/gpu/GrBitmapTextContext.h (right):

https://codereview.chromium.org/45363002/diff/50005/include/gpu/GrBitmapTextC...
include/gpu/GrBitmapTextContext.h:20: GrBitmapTextContext(GrContext*, const
GrPaint&, GrColor);
On 2013/10/28 13:12:21, bsalomon wrote:
> Since everywhere else GrColor is a premul color, maybe we should pass as
SkColor
> and convert in the text context? I'm concerned about opening the door to
non-PM
> GrColors in public APIs as it could get confusing.

Done.

https://codereview.chromium.org/45363002/diff/50005/src/gpu/GrBitmapTextConte...
File src/gpu/GrBitmapTextContext.cpp (right):

https://codereview.chromium.org/45363002/diff/50005/src/gpu/GrBitmapTextConte...
src/gpu/GrBitmapTextContext.cpp:66: bool lcdAlpha = false;
On 2013/10/28 13:12:21, bsalomon wrote:
> this and the below code guarded by this var don't appear to be used anymore.

Done.

[jvanverth1, 2013-10-28 14:48:06]

Fixed the alpha issue, and removed the nonpremultcolor function from SkGr.h
because it was getting too specialized.

[bsalomon, 2013-10-28 15:00:16]

lgtm

[commit-bot: I haz the power, 2013-10-28 15:02:50]

CQ is trying da patch. Follow status at
https://skia-tree-status.appspot.com/cq/jvanverth@google.com/45363002/240002

[commit-bot: I haz the power, 2013-10-28 15:13:53]

Change committed as 11980