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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. */ #define SkColorSpacePrintf(...) static inline bool color_space_almost_equal(float a, float b) { return SkTAbs(a - b) < 0.01f; } static inline bool is_zero_to_one(float v) { return (0.0f <= v) && (v <= 1.0f); } 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 (!is_zero_to_one(coeffs.fD)) { return false; } if (coeffs.fD == 0.0f) { // Y = (aX + b)^g + c 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 = eX + f for always if (0.0f == coeffs.fE) { SkColorSpacePrintf("E 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 E 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 color_space_almost_equal(1.0f / 1.055f, coeffs.fA) && color_space_almost_equal(0.055f / 1.055f, coeffs.fB) && color_space_almost_equal(1.0f / 12.92f, coeffs.fC) && color_space_almost_equal(0.04045f, coeffs.fD) && color_space_almost_equal(0.00000f, coeffs.fE) && color_space_almost_equal(0.00000f, coeffs.fF) && color_space_almost_equal(2.40000f, coeffs.fG); } static inline bool is_almost_2dot2(const SkColorSpaceTransferFn& coeffs) { return color_space_almost_equal(1.0f, coeffs.fA) && color_space_almost_equal(0.0f, coeffs.fB) && color_space_almost_equal(0.0f, coeffs.fC) && color_space_almost_equal(0.0f, coeffs.fD) && color_space_almost_equal(0.0f, coeffs.fE) && color_space_almost_equal(0.0f, coeffs.fF) && color_space_almost_equal(2.2f, coeffs.fG); }