1/*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef Gr1DKernelEffect_DEFINED
9#define Gr1DKernelEffect_DEFINED
10
11#include "GrSingleTextureEffect.h"
12#include "SkMatrix.h"
13
14/**
15 * Base class for 1D kernel effects. The kernel operates either in X or Y and
16 * has a pixel radius. The kernel is specified in the src texture's space
17 * and the kernel center is pinned to a texel's center. The radius specifies
18 * the number of texels on either side of the center texel in X or Y that are
19 * read. Since the center pixel is also read, the total width is one larger than
20 * two times the radius.
21 */
22
23class Gr1DKernelEffect : public GrSingleTextureEffect {
24
25public:
26    enum Direction {
27        kX_Direction,
28        kY_Direction,
29    };
30
31    Gr1DKernelEffect(GrTexture* texture,
32                     Direction direction,
33                     int radius)
34        : GrSingleTextureEffect(texture, GrCoordTransform::MakeDivByTextureWHMatrix(texture))
35        , fDirection(direction)
36        , fRadius(radius) {}
37
38    virtual ~Gr1DKernelEffect() {};
39
40    static int WidthFromRadius(int radius) { return 2 * radius + 1; }
41
42    int radius() const { return fRadius; }
43    int width() const { return WidthFromRadius(fRadius); }
44    Direction direction() const { return fDirection; }
45
46private:
47
48    Direction       fDirection;
49    int             fRadius;
50
51    typedef GrSingleTextureEffect INHERITED;
52};
53
54#endif
55