src/core/SkMatrixImageFilter.h

/*
 * Copyright 2014 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 SkMatrixImageFilter_DEFINED
#define SkMatrixImageFilter_DEFINED

#include "include/core/SkFlattenable.h"
#include "include/core/SkMatrix.h"
#include "src/core/SkImageFilter_Base.h"

/*! \class SkMatrixImageFilter
    Matrix transformation image filter.  This filter draws its source
    input transformed by the given matrix.
 */

// TODO(michaelludwig): Once SkCanvas no longer relies on this for handling complex CTMs with
// filters, this class declaration can be hidden in its cpp file, header deleted, and cpp moved
// into src/effects/imagefilters along with all the other image filters.
class SkMatrixImageFilter : public SkImageFilter_Base {
public:
    /** Construct a 2D transformation image filter.
     *  @param transform     The matrix to apply when drawing the src bitmap
     *  @param sampling      What sampling technique to apply when scaling.
     *  @param input         The input image filter.  If nullptr, the src bitmap
     *                       passed to filterImage() is used instead.
     */

    static sk_sp<SkImageFilter> Make(const SkMatrix& transform,
                                     const SkSamplingOptions& sampling,
                                     sk_sp<SkImageFilter> input);

    SkRect computeFastBounds(const SkRect&) const override;

protected:
    SkMatrixImageFilter(const SkMatrix& transform,
                        const SkSamplingOptions&,
                        sk_sp<SkImageFilter> input);
    void flatten(SkWriteBuffer&) const override;

    sk_sp<SkSpecialImage> onFilterImage(const Context&, SkIPoint* offset) const override;
    SkIRect onFilterNodeBounds(const SkIRect& src, const SkMatrix& ctm,
                               MapDirection, const SkIRect* inputRect) const override;

private:
    SK_FLATTENABLE_HOOKS(SkMatrixImageFilter)

    SkMatrix            fTransform;
    SkSamplingOptions   fSampling;
    using INHERITED = SkImageFilter_Base;
};

#endif