src/core/SkColorSpaceXformSteps.h

/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SkColorSpaceXformSteps_DEFINED
#define SkColorSpaceXformSteps_DEFINED

#include "include/core/SkColorSpace.h"
#include "include/core/SkImageInfo.h"

class SkRasterPipeline;

struct SkColorSpaceXformSteps {
    // Returns true if SkColorSpaceXformSteps must be applied
    // to draw content in `src` into a destination in `dst`.
    static bool Required(SkColorSpace* src, SkColorSpace* dst);

    struct Flags {
        bool unpremul         = false;
        bool linearize        = false;
        bool gamut_transform  = false;
        bool encode           = false;
        bool premul           = false;

        uint32_t mask() const {
            return (unpremul        ?  1 : 0)
                 | (linearize       ?  2 : 0)
                 | (gamut_transform ?  4 : 0)
                 | (encode          ?  8 : 0)
                 | (premul          ? 16 : 0);
        }
    };

    SkColorSpaceXformSteps(SkColorSpace* src, SkAlphaType srcAT,
                           SkColorSpace* dst, SkAlphaType dstAT);

    void apply(float rgba[4]) const;
    void apply(SkRasterPipeline*, bool src_is_normalized) const;

    void apply(SkRasterPipeline* p, SkColorType srcCT) const {
    #if 0
        this->apply(p, srcCT < kRGBA_F16_SkColorType);
    #else
        // F16Norm is normalized, but to make diffing with F16 easier we
        // intentionally take the slower, non-normalized path here.
        this->apply(p, srcCT < kRGBA_F16Norm_SkColorType);
    #endif
    }

    Flags flags;

    bool srcTF_is_sRGB,
         dstTF_is_sRGB;
    skcms_TransferFunction srcTF,     // Apply for linearize.
                           dstTFInv;  // Apply for encode.
    float src_to_dst_matrix[9];       // Apply this 3x3 column-major matrix for gamut_transform.
};

#endif//SkColorSpaceXformSteps_DEFINED