first cut at HQ GPU scaling; refactored existing bicubic scaler

include/effects/SkBicubicImageFilter.h

 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkBicubicImageFilter_DEFINED
 #define SkBicubicImageFilter_DEFINED
 
@@ skipping 16 matching lines @@
                             passed to filterImage() is used instead.
     */
 
     SkBicubicImageFilter(const SkSize& scale, const SkScalar coefficients[16],
                          SkImageFilter* input = NULL);
     static SkBicubicImageFilter* CreateMitchell(const SkSize& scale, SkImageFilter* input = NULL);
     virtual ~SkBicubicImageFilter();
 
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBicubicImageFilter)
 
+    static const SkScalar fMitchellCoefficients[16];

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

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.

+
 protected:
     SkBicubicImageFilter(SkFlattenableReadBuffer& buffer);
     virtual void flatten(SkFlattenableWriteBuffer&) const SK_OVERRIDE;
 
     virtual bool onFilterImage(Proxy*, const SkBitmap& src, const SkMatrix&,
                                SkBitmap* result, SkIPoint* loc) SK_OVERRIDE;
 
 #if SK_SUPPORT_GPU
     virtual bool canFilterImageGPU() const SK_OVERRIDE { return true; }
     virtual bool filterImageGPU(Proxy* proxy, const SkBitmap& src, const SkMatrix& ctm,
                                 SkBitmap* result, SkIPoint* offset) SK_OVERRIDE;
 #endif
 
 private:
     SkSize    fScale;
     SkScalar  fCoefficients[16];
     typedef SkImageFilter INHERITED;
 };
 
 #endif