/* * 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 SkColorSpacePriv_DEFINED #define SkColorSpacePriv_DEFINED #include #include "SkColorSpace.h" #include "SkFixed.h" #define SkColorSpacePrintf(...) static constexpr float gSRGB_toXYZD50[] { 0.4360747f, 0.3850649f, 0.1430804f, // Rx, Gx, Bx 0.2225045f, 0.7168786f, 0.0606169f, // Ry, Gy, By 0.0139322f, 0.0971045f, 0.7141733f, // Rz, Gz, Bz }; static constexpr float gAdobeRGB_toXYZD50[] { // 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), // Rx, Gx, Bx SkFixedToFloat(0x4fa5), SkFixedToFloat(0xa02c), SkFixedToFloat(0x102f), // Ry, Gy, By SkFixedToFloat(0x04fc), SkFixedToFloat(0x0f95), SkFixedToFloat(0xbe9c), // Rz, Gz, Bz }; static constexpr float gDCIP3_toXYZD50[] { 0.515102f, 0.291965f, 0.157153f, // Rx, Gx, Bx 0.241182f, 0.692236f, 0.0665819f, // Ry, Gy, By -0.00104941f, 0.0418818f, 0.784378f, // Rz, Gz, Bz }; static constexpr float gRec2020_toXYZD50[] { 0.673459f, 0.165661f, 0.125100f, // Rx, Gx, Bx 0.279033f, 0.675338f, 0.0456288f, // Ry, Gy, By -0.00193139f, 0.0299794f, 0.797162f, // Rz, Gz, Bz }; // A gamut narrower than sRGB, useful for testing. static constexpr float gNarrow_toXYZD50[] { 0.190974f, 0.404865f, 0.368380f, 0.114746f, 0.582937f, 0.302318f, 0.032925f, 0.153615f, 0.638669f, }; static constexpr SkColorSpaceTransferFn gSRGB_TransferFn = { 2.4f, 1.0f / 1.055f, 0.055f / 1.055f, 1.0f / 12.92f, 0.04045f, 0.0f, 0.0f }; static constexpr SkColorSpaceTransferFn g2Dot2_TransferFn = { 2.2f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f }; static constexpr SkColorSpaceTransferFn gLinear_TransferFn = { 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f }; static constexpr SkColorSpaceTransferFn gDCIP3_TransferFn = { 2.399994f, 0.947998047f, 0.0520019531f, 0.0769958496f, 0.0390014648f, 0.0f, 0.0f }; static inline void to_xyz_d50(SkMatrix44* toXYZD50, SkColorSpace::Gamut gamut) { switch (gamut) { case SkColorSpace::kSRGB_Gamut: toXYZD50->set3x3RowMajorf(gSRGB_toXYZD50); break; case SkColorSpace::kAdobeRGB_Gamut: toXYZD50->set3x3RowMajorf(gAdobeRGB_toXYZD50); break; case SkColorSpace::kDCIP3_D65_Gamut: toXYZD50->set3x3RowMajorf(gDCIP3_toXYZD50); break; case SkColorSpace::kRec2020_Gamut: toXYZD50->set3x3RowMajorf(gRec2020_toXYZD50); break; } } static inline bool color_space_almost_equal(float a, float b) { return SkTAbs(a - b) < 0.01f; } // Let's use a stricter version for transfer functions. Worst case, these are encoded // in ICC format, which offers 16-bits of fractional precision. static inline bool transfer_fn_almost_equal(float a, float b) { return SkTAbs(a - b) < 0.001f; } static inline bool is_zero_to_one(float v) { // Because we allow a value just barely larger than 1, the client can use an // entirely linear transfer function. return (0.0f <= v) && (v <= nextafterf(1.0f, 2.0f)); } static inline bool is_valid_transfer_fn(const SkColorSpaceTransferFn& coeffs) { if (SkScalarIsNaN(coeffs.fA) || SkScalarIsNaN(coeffs.fB) || SkScalarIsNaN(coeffs.fC) || SkScalarIsNaN(coeffs.fD) || SkScalarIsNaN(coeffs.fE) || SkScalarIsNaN(coeffs.fF) || SkScalarIsNaN(coeffs.fG)) { return false; } if (coeffs.fD < 0.0f) { return false; } if (coeffs.fD == 0.0f) { // Y = (aX + b)^g + e for always if (0.0f == coeffs.fA || 0.0f == coeffs.fG) { SkColorSpacePrintf("A or G is zero, constant transfer function " "is nonsense"); return false; } } if (coeffs.fD >= 1.0f) { // Y = cX + f for always if (0.0f == coeffs.fC) { SkColorSpacePrintf("C is zero, constant transfer function is " "nonsense"); return false; } } if ((0.0f == coeffs.fA || 0.0f == coeffs.fG) && 0.0f == coeffs.fC) { SkColorSpacePrintf("A or G, and C are zero, constant transfer function " "is nonsense"); return false; } if (coeffs.fC < 0.0f) { SkColorSpacePrintf("Transfer function must be increasing"); return false; } if (coeffs.fA < 0.0f || coeffs.fG < 0.0f) { SkColorSpacePrintf("Transfer function must be positive or increasing"); return false; } return true; } static inline bool is_almost_srgb(const SkColorSpaceTransferFn& coeffs) { return transfer_fn_almost_equal(gSRGB_TransferFn.fA, coeffs.fA) && transfer_fn_almost_equal(gSRGB_TransferFn.fB, coeffs.fB) && transfer_fn_almost_equal(gSRGB_TransferFn.fC, coeffs.fC) && transfer_fn_almost_equal(gSRGB_TransferFn.fD, coeffs.fD) && transfer_fn_almost_equal(gSRGB_TransferFn.fE, coeffs.fE) && transfer_fn_almost_equal(gSRGB_TransferFn.fF, coeffs.fF) && transfer_fn_almost_equal(gSRGB_TransferFn.fG, coeffs.fG); } static inline bool is_almost_2dot2(const SkColorSpaceTransferFn& coeffs) { return transfer_fn_almost_equal(1.0f, coeffs.fA) && transfer_fn_almost_equal(0.0f, coeffs.fB) && transfer_fn_almost_equal(0.0f, coeffs.fE) && transfer_fn_almost_equal(2.2f, coeffs.fG) && coeffs.fD <= 0.0f; } static inline bool is_almost_linear(const SkColorSpaceTransferFn& coeffs) { // OutputVal = InputVal ^ 1.0f const bool linearExp = transfer_fn_almost_equal(1.0f, coeffs.fA) && transfer_fn_almost_equal(0.0f, coeffs.fB) && transfer_fn_almost_equal(0.0f, coeffs.fE) && transfer_fn_almost_equal(1.0f, coeffs.fG) && coeffs.fD <= 0.0f; // OutputVal = 1.0f * InputVal const bool linearFn = transfer_fn_almost_equal(1.0f, coeffs.fC) && transfer_fn_almost_equal(0.0f, coeffs.fF) && coeffs.fD >= 1.0f; return linearExp || linearFn; } static inline bool is_just_gamma(const SkColorSpaceTransferFn& coeffs) { return transfer_fn_almost_equal(coeffs.fA, 1.0f) && transfer_fn_almost_equal(coeffs.fB, 0.0f) && transfer_fn_almost_equal(coeffs.fC, 0.0f) && transfer_fn_almost_equal(coeffs.fD, 0.0f) && transfer_fn_almost_equal(coeffs.fE, 0.0f) && transfer_fn_almost_equal(coeffs.fF, 0.0f); } static inline void value_to_parametric(SkColorSpaceTransferFn* coeffs, float exponent) { coeffs->fA = 1.0f; coeffs->fB = 0.0f; coeffs->fC = 0.0f; coeffs->fD = 0.0f; coeffs->fE = 0.0f; coeffs->fF = 0.0f; coeffs->fG = exponent; } static inline bool named_to_parametric(SkColorSpaceTransferFn* coeffs, SkGammaNamed gammaNamed) { switch (gammaNamed) { case kSRGB_SkGammaNamed: *coeffs = gSRGB_TransferFn; return true; case k2Dot2Curve_SkGammaNamed: *coeffs = g2Dot2_TransferFn; return true; case kLinear_SkGammaNamed: *coeffs = gLinear_TransferFn; return true; default: return false; } } // Return raw pointers to commonly used SkColorSpaces. // No need to ref/unref these, but if you do, do it in pairs. SkColorSpace* sk_srgb_singleton(); SkColorSpace* sk_srgb_linear_singleton(); #endif // SkColorSpacePriv_DEFINED