SkMatrixConvolutionImageFilter.h

/*
 * Copyright 2012 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 SkMatrixConvolutionImageFilter_DEFINED
#define SkMatrixConvolutionImageFilter_DEFINED

#include "SkImageFilter.h"
#include "SkScalar.h"
#include "SkSize.h"
#include "SkPoint.h"

class SkBitmap;

class SK_API SkMatrixConvolutionImageFilter : public SkImageFilter {
public:
    enum TileMode {
      kClamp_TileMode = 0,         
      kRepeat_TileMode,        
      kClampToBlack_TileMode,  
      kMax_TileMode = kClampToBlack_TileMode
    };

    ~SkMatrixConvolutionImageFilter() override;

    static sk_sp<SkImageFilter> Make(const SkISize& kernelSize,
                                     const SkScalar* kernel,
                                     SkScalar gain,
                                     SkScalar bias,
                                     const SkIPoint& kernelOffset,
                                     TileMode tileMode,
                                     bool convolveAlpha,
                                     sk_sp<SkImageFilter> input,
                                     const CropRect* cropRect = nullptr);

    SK_TO_STRING_OVERRIDE()
    SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkMatrixConvolutionImageFilter)

#ifdef SK_SUPPORT_LEGACY_IMAGEFILTER_PTR
    static SkImageFilter* Create(const SkISize& kernelSize,
                                 const SkScalar* kernel,
                                 SkScalar gain,
                                 SkScalar bias,
                                 const SkIPoint& kernelOffset,
                                 TileMode tileMode,
                                 bool convolveAlpha,
                                 SkImageFilter* input = NULL,
                                 const CropRect* cropRect = NULL) {
        return Make(kernelSize, kernel, gain, bias, kernelOffset, tileMode, convolveAlpha,
                    sk_ref_sp<SkImageFilter>(input), cropRect).release();
    }
#endif

protected:
    SkMatrixConvolutionImageFilter(const SkISize& kernelSize,
                                   const SkScalar* kernel,
                                   SkScalar gain,
                                   SkScalar bias,
                                   const SkIPoint& kernelOffset,
                                   TileMode tileMode,
                                   bool convolveAlpha,
                                   sk_sp<SkImageFilter> input,
                                   const CropRect* cropRect);
    void flatten(SkWriteBuffer&) const override;

    sk_sp<SkSpecialImage> onFilterImage(SkSpecialImage* source, const Context&,
                                        SkIPoint* offset) const override;
    SkIRect onFilterNodeBounds(const SkIRect&, const SkMatrix&, MapDirection) const override;
    bool affectsTransparentBlack() const override;

private:
    SkISize   fKernelSize;
    SkScalar* fKernel;
    SkScalar  fGain;
    SkScalar  fBias;
    SkIPoint  fKernelOffset;
    TileMode  fTileMode;
    bool      fConvolveAlpha;

    template <class PixelFetcher, bool convolveAlpha>
    void filterPixels(const SkBitmap& src,
                      SkBitmap* result,
                      const SkIRect& rect,
                      const SkIRect& bounds) const;
    template <class PixelFetcher>
    void filterPixels(const SkBitmap& src,
                      SkBitmap* result,
                      const SkIRect& rect,
                      const SkIRect& bounds) const;
    void filterInteriorPixels(const SkBitmap& src,
                              SkBitmap* result,
                              const SkIRect& rect,
                              const SkIRect& bounds) const;
    void filterBorderPixels(const SkBitmap& src,
                            SkBitmap* result,
                            const SkIRect& rect,
                            const SkIRect& bounds) const;

    typedef SkImageFilter INHERITED;
};

#endif