michael@0: /*
michael@0:  * Copyright 2012 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #ifndef Gr1DKernelEffect_DEFINED
michael@0: #define Gr1DKernelEffect_DEFINED
michael@0: 
michael@0: #include "GrSingleTextureEffect.h"
michael@0: #include "SkMatrix.h"
michael@0: 
michael@0: /**
michael@0:  * Base class for 1D kernel effects. The kernel operates either in X or Y and
michael@0:  * has a pixel radius. The kernel is specified in the src texture's space
michael@0:  * and the kernel center is pinned to a texel's center. The radius specifies
michael@0:  * the number of texels on either side of the center texel in X or Y that are
michael@0:  * read. Since the center pixel is also read, the total width is one larger than
michael@0:  * two times the radius.
michael@0:  */
michael@0: 
michael@0: class Gr1DKernelEffect : public GrSingleTextureEffect {
michael@0: 
michael@0: public:
michael@0:     enum Direction {
michael@0:         kX_Direction,
michael@0:         kY_Direction,
michael@0:     };
michael@0: 
michael@0:     Gr1DKernelEffect(GrTexture* texture,
michael@0:                      Direction direction,
michael@0:                      int radius)
michael@0:         : GrSingleTextureEffect(texture, MakeDivByTextureWHMatrix(texture))
michael@0:         , fDirection(direction)
michael@0:         , fRadius(radius) {}
michael@0: 
michael@0:     virtual ~Gr1DKernelEffect() {};
michael@0: 
michael@0:     static int WidthFromRadius(int radius) { return 2 * radius + 1; }
michael@0: 
michael@0:     int radius() const { return fRadius; }
michael@0:     int width() const { return WidthFromRadius(fRadius); }
michael@0:     Direction direction() const { return fDirection; }
michael@0: 
michael@0: private:
michael@0: 
michael@0:     Direction       fDirection;
michael@0:     int             fRadius;
michael@0: 
michael@0:     typedef GrSingleTextureEffect INHERITED;
michael@0: };
michael@0: 
michael@0: #endif