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/*
* Copyright 2016 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkColorSpace_A2B_DEFINED
#define SkColorSpace_A2B_DEFINED
#include "SkColorSpace_Base.h"
// An alternative SkColorSpace that represents all the color space data that
// is stored in an A2B0 ICC tag. This allows us to use alternative profile
// connection spaces (CIELAB instead of just CIEXYZ), use color-lookup-tables
// to do color space transformations not representable as TRC functions or
// matrix operations, as well as have multiple TRC functions. The CLUT also has
// the potential to allow conversion from input color spaces with a different
// number of channels such as CMYK (4) or GRAY (1), but that is not supported yet.
//
// Evaluation is done: A-curve => CLUT => M-curve => Matrix => B-curve
//
// There are also multi-processing-elements in the A2B0 tag which allow you to
// combine these 3 primitives (TRC, CLUT, matrix) in any order/quantitiy,
// but support for that is not implemented.
class SkColorSpace_A2B : public SkColorSpace_Base {
public:
const SkMatrix44* toXYZD50() const override {
// the matrix specified in A2B0 profiles is not necessarily
// a to-XYZ matrix, as to-Lab is supported as well so returning
// that could be misleading. Additionally, B-curves are applied
// after the matrix is, but a toXYZD50 matrix is the last thing
// applied in order to get into the (XYZ) profile connection space.
return nullptr;
}
const SkMatrix44* fromXYZD50() const override {
// See toXYZD50()'s comment. Also, A2B0 profiles are not supported
// as destination color spaces, so an inverse matrix is never wanted.
return nullptr;
}
bool onGammaCloseToSRGB() const override {
// There is no single gamma curve in an A2B0 profile
return false;
}
bool onGammaIsLinear() const override {
// There is no single gamma curve in an A2B0 profile
return false;
}
SkGammaNamed aCurveNamed() const { return fACurveNamed; }
const SkGammas* aCurve() const { return fACurve.get(); }
const SkColorLookUpTable* colorLUT() const { return fColorLUT.get(); }
SkGammaNamed mCurveNamed() const { return fMCurveNamed; }
const SkGammas* mCurve() const { return fMCurve.get(); }
const SkMatrix44& matrix() const { return fMatrix; }
SkGammaNamed bCurveNamed() const { return fBCurveNamed; }
const SkGammas* bCurve() const { return fBCurve.get(); }
// the intermediate profile connection space that this color space
// represents the transformation to
enum class PCS : uint8_t {
kLAB, // CIELAB
kXYZ // CIEXYZ
};
PCS pcs() const { return fPCS; }
Type type() const override { return Type::kA2B; }
private:
SkColorSpace_A2B(SkGammaNamed aCurveNamed, sk_sp<SkGammas> aCurve,
sk_sp<SkColorLookUpTable> colorLUT,
SkGammaNamed mCurveNamed, sk_sp<SkGammas> mCurve,
const SkMatrix44& matrix,
SkGammaNamed bCurveNamed, sk_sp<SkGammas> bCurve,
PCS pcs, sk_sp<SkData> profileData);
const SkGammaNamed fACurveNamed;
sk_sp<SkGammas> fACurve;
sk_sp<SkColorLookUpTable> fColorLUT;
const SkGammaNamed fMCurveNamed;
sk_sp<SkGammas> fMCurve;
SkMatrix44 fMatrix;
const SkGammaNamed fBCurveNamed;
sk_sp<SkGammas> fBCurve;
PCS fPCS;
friend class SkColorSpace;
typedef SkColorSpace_Base INHERITED;
};
#endif
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