text: /*
   * 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_DEFINED
  #define SkColorSpace_DEFINED
  
  #include "include/core/SkMatrix44.h"
  #include "include/core/SkRefCnt.h"
  #include "include/private/SkFixed.h"
  #include "include/private/SkOnce.h"
  #include "include/third_party/skcms/skcms.h"
  #include <memory>
  
  class SkData;
  
  /**
   *  Describes a color gamut with primaries and a white point.
   */
  struct SK_API SkColorSpacePrimaries {
      float fRX;
      float fRY;
      float fGX;
      float fGY;
      float fBX;
      float fBY;
      float fWX;
      float fWY;
  
      /**
       *  Convert primaries and a white point to a toXYZD50 matrix, the preferred color gamut
       *  representation of SkColorSpace.
       */
      bool toXYZD50(skcms_Matrix3x3* toXYZD50) const;
  };
  
  namespace SkNamedTransferFn {
  
  // Like SkNamedGamut::kSRGB, keeping this bitwise exactly the same as skcms makes things fastest.
  static constexpr skcms_TransferFunction kSRGB =
      { 2.4f, (float)(1/1.055), (float)(0.055/1.055), (float)(1/12.92), 0.04045f, 0.0f, 0.0f };
  
  static constexpr skcms_TransferFunction k2Dot2 =
      { 2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
  
  static constexpr skcms_TransferFunction kLinear =
      { 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f };
  
  static constexpr skcms_TransferFunction kRec2020 =
      {2.22222f, 0.909672f, 0.0903276f, 0.222222f, 0.0812429f, 0, 0};
  
  static constexpr skcms_TransferFunction kPQ =
      {-2.0f, -107/128.0f, 1.0f, 32/2523.0f, 2413/128.0f, -2392/128.0f, 8192/1305.0f };
  
  static constexpr skcms_TransferFunction kHLG =
      {-3.0f, 2.0f, 2.0f, 1/0.17883277f, 0.28466892f, 0.55991073f, 0.0f };
  
  }
  
  namespace SkNamedGamut {
  
  static constexpr skcms_Matrix3x3 kSRGB = {{
      // ICC fixed-point (16.16) representation, taken from skcms. Please keep them exactly in sync.
      // 0.436065674f, 0.385147095f, 0.143066406f,
      // 0.222488403f, 0.716873169f, 0.060607910f,
      // 0.013916016f, 0.097076416f, 0.714096069f,
      { SkFixedToFloat(0x6FA2), SkFixedToFloat(0x6299), SkFixedToFloat(0x24A0) },
      { SkFixedToFloat(0x38F5), SkFixedToFloat(0xB785), SkFixedToFloat(0x0F84) },
      { SkFixedToFloat(0x0390), SkFixedToFloat(0x18DA), SkFixedToFloat(0xB6CF) },
  }};
  
  static constexpr skcms_Matrix3x3 kAdobeRGB = {{
      // ICC fixed-point (16.16) repesentation of:
      // 0.60974, 0.20528, 0.14919,
      // 0.31111, 0.62567, 0.06322,
      // 0.01947, 0.06087, 0.74457,
      { SkFixedToFloat(0x9c18), SkFixedToFloat(0x348d), SkFixedToFloat(0x2631) },
      { SkFixedToFloat(0x4fa5), SkFixedToFloat(0xa02c), SkFixedToFloat(0x102f) },
      { SkFixedToFloat(0x04fc), SkFixedToFloat(0x0f95), SkFixedToFloat(0xbe9c) },
  }};
  
  static constexpr skcms_Matrix3x3 kDCIP3 = {{
      {  0.515102f,   0.291965f,  0.157153f  },
      {  0.241182f,   0.692236f,  0.0665819f },
      { -0.00104941f, 0.0418818f, 0.784378f  },
  }};
  
  static constexpr skcms_Matrix3x3 kRec2020 = {{
      {  0.673459f,   0.165661f,  0.125100f  },
      {  0.279033f,   0.675338f,  0.0456288f },
      { -0.00193139f, 0.0299794f, 0.797162f  },
  }};
  
  static constexpr skcms_Matrix3x3 kXYZ = {{
      { 1.0f, 0.0f, 0.0f },
      { 0.0f, 1.0f, 0.0f },
      { 0.0f, 0.0f, 1.0f },
  }};
  
  }
  
  class SK_API SkColorSpace : public SkNVRefCnt<SkColorSpace> {
  public:
      /**
       *  Create the sRGB color space.
       */
      static sk_sp<SkColorSpace> MakeSRGB();
  
      /**
       *  Colorspace with the sRGB primaries, but a linear (1.0) gamma.
       */
      static sk_sp<SkColorSpace> MakeSRGBLinear();
  
      /**
       *  Create an SkColorSpace from a transfer function and a row-major 3x3 transformation to XYZ.
       */
      static sk_sp<SkColorSpace> MakeRGB(const skcms_TransferFunction& transferFn,
                                         const skcms_Matrix3x3& toXYZ);
  
      /**
       *  Create an SkColorSpace from a parsed (skcms) ICC profile.
       */
      static sk_sp<SkColorSpace> Make(const skcms_ICCProfile&);
  
      /**
       *  Convert this color space to an skcms ICC profile struct.
       */
      void toProfile(skcms_ICCProfile*) const;
  
      /**
       *  Returns true if the color space gamma is near enough to be approximated as sRGB.
       */
      bool gammaCloseToSRGB() const;
  
      /**
       *  Returns true if the color space gamma is linear.
       */
      bool gammaIsLinear() const;
  
      /**
       *  Sets |fn| to the transfer function from this color space. Returns true if the transfer
       *  function can be represented as coefficients to the standard ICC 7-parameter equation.
       *  Returns false otherwise (eg, PQ, HLG).
       */
      bool isNumericalTransferFn(skcms_TransferFunction* fn) const;
  
      /**
       *  Returns true and sets |toXYZD50| if the color gamut can be described as a matrix.
       *  Returns false otherwise.
       */
      bool toXYZD50(skcms_Matrix3x3* toXYZD50) const;
  
      /**
       *  Returns a hash of the gamut transformation to XYZ D50. Allows for fast equality checking
       *  of gamuts, at the (very small) risk of collision.
       */
      uint32_t toXYZD50Hash() const { return fToXYZD50Hash; }
  
      /**
       *  Returns a color space with the same gamut as this one, but with a linear gamma.
       *  For color spaces whose gamut can not be described in terms of XYZ D50, returns
       *  linear sRGB.
       */
      sk_sp<SkColorSpace> makeLinearGamma() const;
  
      /**
       *  Returns a color space with the same gamut as this one, with with the sRGB transfer
       *  function. For color spaces whose gamut can not be described in terms of XYZ D50, returns
       *  sRGB.
       */
      sk_sp<SkColorSpace> makeSRGBGamma() const;
  
      /**
       *  Returns a color space with the same transfer function as this one, but with the primary
       *  colors rotated. For any XYZ space, this produces a new color space that maps RGB to GBR
       *  (when applied to a source), and maps RGB to BRG (when applied to a destination). For other
       *  types of color spaces, returns nullptr.
       *
       *  This is used for testing, to construct color spaces that have severe and testable behavior.
       */
      sk_sp<SkColorSpace> makeColorSpin() const;
  
      /**
       *  Returns true if the color space is sRGB.
       *  Returns false otherwise.
       *
       *  This allows a little bit of tolerance, given that we might see small numerical error
       *  in some cases: converting ICC fixed point to float, converting white point to D50,
       *  rounding decisions on transfer function and matrix.
       *
       *  This does not consider a 2.2f exponential transfer function to be sRGB.  While these
       *  functions are similar (and it is sometimes useful to consider them together), this
       *  function checks for logical equality.
       */
      bool isSRGB() const;
  
      /**
       *  Returns nullptr on failure.  Fails when we fallback to serializing ICC data and
       *  the data is too large to serialize.
       */
      sk_sp<SkData> serialize() const;
  
      /**
       *  If |memory| is nullptr, returns the size required to serialize.
       *  Otherwise, serializes into |memory| and returns the size.
       */
      size_t writeToMemory(void* memory) const;
  
      static sk_sp<SkColorSpace> Deserialize(const void* data, size_t length);
  
      /**
       *  If both are null, we return true.  If one is null and the other is not, we return false.
       *  If both are non-null, we do a deeper compare.
       */
      static bool Equals(const SkColorSpace*, const SkColorSpace*);
  
      void       transferFn(float gabcdef[7]) const;  // DEPRECATED: Remove when webview usage is gone
      void       transferFn(skcms_TransferFunction* fn) const;
      void    invTransferFn(skcms_TransferFunction* fn) const;
      void gamutTransformTo(const SkColorSpace* dst, skcms_Matrix3x3* src_to_dst) const;
  
      uint32_t transferFnHash() const { return fTransferFnHash; }
      uint64_t           hash() const { return (uint64_t)fTransferFnHash << 32 | fToXYZD50Hash; }
  
  private:
      friend class SkColorSpaceSingletonFactory;
  
      SkColorSpace(const skcms_TransferFunction& transferFn, const skcms_Matrix3x3& toXYZ);
  
      void computeLazyDstFields() const;
  
      uint32_t                            fTransferFnHash;
      uint32_t                            fToXYZD50Hash;
  
      skcms_TransferFunction              fTransferFn;
      skcms_Matrix3x3                     fToXYZD50;
  
      mutable skcms_TransferFunction      fInvTransferFn;
      mutable skcms_Matrix3x3             fFromXYZD50;
      mutable SkOnce                      fLazyDstFieldsOnce;
  };
  
  #endif
  