Gpu to apply mask gamma.

Gpu to apply mask gamma.

[bungeman, 2012-10-30 20:04:40]

Once the information is in GrTextContext everything is good. Getting that
information is more difficult.

The current steps in creating a glyph mask are (logically):

0. Get something to render the text.
1. Convert this to a linear mask, if needed. (This may include undoing gamma
correction or pulling down from three channel to single channel.)
2. Apply contrast.
3. Apply pre-blend / gamma.

The ugly is in (1) signalling that the device can apply the last N steps itself
and (2) allowing the device to discover the parameters (gamma, contrast, etc)
for the steps it will apply. This change handles (1) with
SkDevice::wantsLinearMasks() which states that the device will apply steps 2 and
3. This change handles (2) by allowing SkGpuDevice to call
SkPaint.descriptorProc(...) with its own proc in order to read out what the
SkScalerContext::Rec would have been had it not requested linear masks. Both of
these approaches could probably use some implementation improvement.

[bsalomon, 2012-10-30 20:52:50]

Any idea what performance of the gamma text is like compared to the current
code?

I upstreamed the changes made in gpu_dev to trunk and some signatures on
GrGLEffect changed (again) :P

https://codereview.appspot.com/6818058/diff/1/include/gpu/GrTextContext.h
File include/gpu/GrTextContext.h (right):

https://codereview.appspot.com/6818058/diff/1/include/gpu/GrTextContext.h#new...
include/gpu/GrTextContext.h:65: GrScalar    fGamma;
style nit: can we align these (or unalign the others).

https://codereview.appspot.com/6818058/diff/1/src/gpu/GrTextContext.cpp
File src/gpu/GrTextContext.cpp (right):

https://codereview.appspot.com/6818058/diff/1/src/gpu/GrTextContext.cpp#newco...
src/gpu/GrTextContext.cpp:39: GrSingleTextureGammaEffect* effect =
SkNEW_ARGS(GrSingleTextureGammaEffect, (
If this is always (kRepeat, false) can't his cons just assume it?

https://codereview.appspot.com/6818058/diff/1/src/gpu/effects/GrSingleTexture...
File src/gpu/effects/GrSingleTextureGammaEffect.h (right):

https://codereview.appspot.com/6818058/diff/1/src/gpu/effects/GrSingleTexture...
src/gpu/effects/GrSingleTextureGammaEffect.h:18: * An effect that merely blits a
single texture; commonly used as a base class.
heh

https://codereview.appspot.com/6818058/diff/1/src/gpu/effects/GrSingleTexture...
src/gpu/effects/GrSingleTextureGammaEffect.h:20: class
GrSingleTextureGammaEffect : public GrEffect {
Can we call it something shorter like GrGammaTextEffect? I dunno that
SingleTexture is very informative to the user of this class.

https://codereview.appspot.com/6818058/diff/1/src/gpu/effects/GrSingleTexture...
src/gpu/effects/GrSingleTextureGammaEffect.h:46: friend class
GrGLSingleTextureGammaEffect;
do we need to be friends or could we just add getters?

[reed1, 2012-10-30 21:09:34]

more and more, I think we should make a small struct that carries these
gamma/contrast/etc. parameters. No idea what to call it....
DeviceCharacteristics?

https://codereview.appspot.com/6818058/diff/1/include/core/SkPaint.h
File include/core/SkPaint.h (right):

https://codereview.appspot.com/6818058/diff/1/include/core/SkPaint.h#newcode967
include/core/SkPaint.h:967: 
So many default/bool parameters. Perhaps we can change these to internal enums
or something, so call sites are clearer.

https://codereview.appspot.com/6818058/diff/1/src/core/SkPaint.cpp
File src/core/SkPaint.cpp (right):

https://codereview.appspot.com/6818058/diff/1/src/core/SkPaint.cpp#newcode1682
src/core/SkPaint.cpp:1682: void SkScalerContext::PostMakeRec(const SkPaint&
paint, SkScalerContext::Rec* rec) {
Can we land this change first? (passing typeface to fonthost)

https://codereview.appspot.com/6818058/diff/1/src/gpu/SkGpuDevice.cpp
File src/gpu/SkGpuDevice.cpp (right):

https://codereview.appspot.com/6818058/diff/1/src/gpu/SkGpuDevice.cpp#newcode...
src/gpu/SkGpuDevice.cpp:1818: }
OK, now I'm sure we have too many bool params :)