first cut at HQ GPU scaling; refactored existing bicubic scaler

add support for high quality image filtering on the GPU

R=bsalomon@google.com, reed@google.com

Committed: https://code.google.com/p/skia/source/detail?r=11087

[bsalomon, 2013-09-03 20:55:17]

https://codereview.chromium.org/23779003/diff/1/include/effects/SkBicubicImag...
File include/effects/SkBicubicImageFilter.h (right):

https://codereview.chromium.org/23779003/diff/1/include/effects/SkBicubicImag...
include/effects/SkBicubicImageFilter.h:37: static const SkScalar
fMitchellCoefficients[16];
style-nit: statics aren't fSomething. Maybe gMitchellCoeffecients or
kMitchellCoeffecients.

(There is some ambiguity in the existing code about whether the 'k' prefix
stands for a Kompile-time of any type or more narrowly just a Kinteger.

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrBicubicEffe...
File src/gpu/effects/GrBicubicEffect.h (right):

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrBicubicEffe...
src/gpu/effects/GrBicubicEffect.h:56: class GrGLBicubicEffect : public
GrGLEffect {
We can move this class defn to the header... no one but GrBicubicEffect should
need to know about this class.

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrHQScaleText...
File src/gpu/effects/GrHQScaleTextureEffect.h (right):

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrHQScaleText...
src/gpu/effects/GrHQScaleTextureEffect.h:8: #ifndef
GrHQScaleTextureEffect_DEFINED
Is this file and the cpp actually used? It looks like you're using the bicubic
effect.

[reed1, 2013-09-03 20:57:37]

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.cpp
File src/core/SkBitmapProcShader.cpp (right):

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.c...
src/core/SkBitmapProcShader.cpp:14: #include "../effects/SkBicubicImageFilter.h"
do we need the path to scope where these headers are?

[humper, 2013-09-03 21:45:53]

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.cpp
File src/core/SkBitmapProcShader.cpp (right):

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.c...
src/core/SkBitmapProcShader.cpp:14: #include "../effects/SkBicubicImageFilter.h"
On 2013/09/03 20:57:37, reed1 wrote:
> do we need the path to scope where these headers are?

Probably not -- this one picks out a file from src/effects; just putting
effects/ in there will pick out include/effects.  I'll move the header.

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrHQScaleText...
File src/gpu/effects/GrHQScaleTextureEffect.h (right):

https://codereview.chromium.org/23779003/diff/1/src/gpu/effects/GrHQScaleText...
src/gpu/effects/GrHQScaleTextureEffect.h:8: #ifndef
GrHQScaleTextureEffect_DEFINED
On 2013/09/03 20:55:17, bsalomon wrote:
> Is this file and the cpp actually used? It looks like you're using the bicubic
> effect.

Nope, this was an unintentional addition.

[bsalomon, 2013-09-04 13:06:14]

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.cpp
File src/core/SkBitmapProcShader.cpp (right):

https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.c...
src/core/SkBitmapProcShader.cpp:14: #include "../effects/SkBicubicImageFilter.h"
On 2013/09/03 21:45:53, humper wrote:
> On 2013/09/03 20:57:37, reed1 wrote:
> > do we need the path to scope where these headers are?
> 
> Probably not -- this one picks out a file from src/effects; just putting
> effects/ in there will pick out include/effects.  I'll move the header.

I think we actually shouldn't have core depend on anything in effects. We pretty
loosey goosey about cross dependencies but effects is still optional from a skia
library build.


Is it just the coeffs that're being shared? Maybe just dupe 'em.

[humper, 2013-09-04 13:09:08]

On 2013/09/04 13:06:14, bsalomon wrote:
>
https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.cpp
> File src/core/SkBitmapProcShader.cpp (right):
> 
>
https://codereview.chromium.org/23779003/diff/1/src/core/SkBitmapProcShader.c...
> src/core/SkBitmapProcShader.cpp:14: #include
"../effects/SkBicubicImageFilter.h"
> On 2013/09/03 21:45:53, humper wrote:
> > On 2013/09/03 20:57:37, reed1 wrote:
> > > do we need the path to scope where these headers are?
> > 
> > Probably not -- this one picks out a file from src/effects; just putting
> > effects/ in there will pick out include/effects.  I'll move the header.
> 
> I think we actually shouldn't have core depend on anything in effects. We
pretty
> loosey goosey about cross dependencies but effects is still optional from a
skia
> library build.
> 
> 
> Is it just the coeffs that're being shared? Maybe just dupe 'em.

Sounds good, I'll dupe em.  Stay tuned.

[bsalomon, 2013-09-04 17:21:48]

https://codereview.chromium.org/23779003/diff/15001/include/effects/SkBicubic...
File include/effects/SkBicubicImageFilter.h (right):

https://codereview.chromium.org/23779003/diff/15001/include/effects/SkBicubic...
include/effects/SkBicubicImageFilter.h:37: static const SkScalar
gMitchellCoefficients[16];
If these are just used in SkBIF.cpp then maybe we don't need them in the header
and can just be non-class-nested static const? Otherwise lgtm.

[reed1, 2013-09-04 17:36:54]

lgtm for the trivial parts

[humper, 2013-09-04 19:24:04]

Committed patchset #4 manually as r11087 (presubmit successful).