1/*
2 * Copyright 2012 The Android Open Source Project
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 SkMatrixConvolutionImageFilter_DEFINED
9#define SkMatrixConvolutionImageFilter_DEFINED
10
11#include "SkImageFilter.h"
12#include "SkScalar.h"
13#include "SkSize.h"
14#include "SkPoint.h"
15
16/*! \class SkMatrixConvolutionImageFilter
17    Matrix convolution image filter.  This filter applies an NxM image
18    processing kernel to a given input image.  This can be used to produce
19    effects such as sharpening, blurring, edge detection, etc.
20 */
21
22class SK_API SkMatrixConvolutionImageFilter : public SkImageFilter {
23public:
24    /*! \enum TileMode */
25    enum TileMode {
26      kClamp_TileMode = 0,         /*!< Clamp to the image's edge pixels. */
27      kRepeat_TileMode,        /*!< Wrap around to the image's opposite edge. */
28      kClampToBlack_TileMode,  /*!< Fill with transparent black. */
29      kMax_TileMode = kClampToBlack_TileMode
30    };
31
32    virtual ~SkMatrixConvolutionImageFilter();
33
34    /** Construct a matrix convolution image filter.
35        @param kernelSize     The kernel size in pixels, in each dimension (N by M).
36        @param kernel         The image processing kernel.  Must contain N * M
37                              elements, in row order.
38        @param gain           A scale factor applied to each pixel after
39                              convolution.  This can be used to normalize the
40                              kernel, if it does not sum to 1.
41        @param bias           A bias factor added to each pixel after convolution.
42        @param kernelOffset   An offset applied to each pixel coordinate before
43                              convolution.  This can be used to center the kernel
44                              over the image (e.g., a 3x3 kernel should have an
45                              offset of {1, 1}).
46        @param tileMode       How accesses outside the image are treated.  (@see
47                              TileMode).
48        @param convolveAlpha  If true, all channels are convolved.  If false,
49                              only the RGB channels are convolved, and
50                              alpha is copied from the source image.
51        @param input          The input image filter.  If NULL, the src bitmap
52                              passed to filterImage() is used instead.
53        @param cropRect       The rectangle to which the output processing will be limited.
54    */
55    static SkMatrixConvolutionImageFilter* Create(const SkISize& kernelSize,
56                                                  const SkScalar* kernel,
57                                                  SkScalar gain,
58                                                  SkScalar bias,
59                                                  const SkIPoint& kernelOffset,
60                                                  TileMode tileMode,
61                                                  bool convolveAlpha,
62                                                  SkImageFilter* input = NULL,
63                                                  const CropRect* cropRect = NULL);
64
65    SK_TO_STRING_OVERRIDE()
66    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkMatrixConvolutionImageFilter)
67
68protected:
69    SkMatrixConvolutionImageFilter(const SkISize& kernelSize,
70                                   const SkScalar* kernel,
71                                   SkScalar gain,
72                                   SkScalar bias,
73                                   const SkIPoint& kernelOffset,
74                                   TileMode tileMode,
75                                   bool convolveAlpha,
76                                   SkImageFilter* input,
77                                   const CropRect* cropRect);
78    void flatten(SkWriteBuffer&) const override;
79
80    virtual bool onFilterImage(Proxy*, const SkBitmap& src, const Context&,
81                               SkBitmap* result, SkIPoint* loc) const override;
82    bool onFilterBounds(const SkIRect&, const SkMatrix&, SkIRect*) const override;
83
84
85#if SK_SUPPORT_GPU
86    virtual bool asFragmentProcessor(GrFragmentProcessor**, GrTexture*, const SkMatrix&,
87                                     const SkIRect& bounds) const override;
88#endif
89
90private:
91    SkISize   fKernelSize;
92    SkScalar* fKernel;
93    SkScalar  fGain;
94    SkScalar  fBias;
95    SkIPoint  fKernelOffset;
96    TileMode  fTileMode;
97    bool      fConvolveAlpha;
98    typedef SkImageFilter INHERITED;
99
100    template <class PixelFetcher, bool convolveAlpha>
101    void filterPixels(const SkBitmap& src,
102                      SkBitmap* result,
103                      const SkIRect& rect,
104                      const SkIRect& bounds) const;
105    template <class PixelFetcher>
106    void filterPixels(const SkBitmap& src,
107                      SkBitmap* result,
108                      const SkIRect& rect,
109                      const SkIRect& bounds) const;
110    void filterInteriorPixels(const SkBitmap& src,
111                              SkBitmap* result,
112                              const SkIRect& rect,
113                              const SkIRect& bounds) const;
114    void filterBorderPixels(const SkBitmap& src,
115                            SkBitmap* result,
116                            const SkIRect& rect,
117                            const SkIRect& bounds) const;
118};
119
120#endif
121