/*

 * Copyright 2020 Google Inc.

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#ifndef SkSamplingPriv_DEFINED

#define SkSamplingPriv_DEFINED

#include "include/core/SkSamplingOptions.h"

class SkReadBuffer;

class SkWriteBuffer;

// Private copy of SkFilterQuality, just for legacy deserialization

// Matches values in SkFilterQuality

enum SkLegacyFQ {

    kNone_SkLegacyFQ   = 0,    //!< nearest-neighbor; fastest but lowest quality

    kLow_SkLegacyFQ    = 1,    //!< bilerp

    kMedium_SkLegacyFQ = 2,    //!< bilerp + mipmaps; good for down-scaling

    kHigh_SkLegacyFQ   = 3,    //!< bicubic resampling; slowest but good quality

    kLast_SkLegacyFQ = kHigh_SkLegacyFQ,

};

// Matches values in SkSamplingOptions::MediumBehavior

enum SkMediumAs {

    kNearest_SkMediumAs,

    kLinear_SkMediumAs,

};

class SkSamplingPriv {

public:

    enum {

        kFlatSize = 3 * sizeof(uint32_t)  // bool32 + [2 floats | 2 ints]

    };

    // Returns true if the sampling can be ignored when the CTM is identity.

    static bool NoChangeWithIdentityMatrix(const SkSamplingOptions& sampling) {

        // If B == 0, the cubic resampler should have no effect for identity matrices

        // https://entropymine.com/imageworsener/bicubic/

        return !sampling.useCubic || sampling.cubic.B == 0;

    }

    static SkSamplingOptions Read(SkReadBuffer&);

    static void Write(SkWriteBuffer&, const SkSamplingOptions&);

    static SkSamplingOptions FromFQ(SkLegacyFQ, SkMediumAs = kNearest_SkMediumAs);

};

#endif