| /* |
| * Copyright (C) 2017-2021 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #pragma once |
| |
| #include "ColorComponents.h" |
| #include "ColorTypes.h" |
| #include <algorithm> |
| #include <cmath> |
| #include <functional> |
| #include <math.h> |
| |
| namespace WebCore { |
| |
| SRGBA<float> premultiplied(const SRGBA<float>&); |
| SRGBA<float> unpremultiplied(const SRGBA<float>&); |
| |
| SRGBA<uint8_t> premultipliedFlooring(SRGBA<uint8_t>); |
| SRGBA<uint8_t> premultipliedCeiling(SRGBA<uint8_t>); |
| SRGBA<uint8_t> unpremultiplied(SRGBA<uint8_t>); |
| |
| uint8_t convertPrescaledSRGBAFloatToSRGBAByte(float); |
| |
| template<typename T> T convertByteAlphaTo(uint8_t); |
| template<typename T> T convertFloatAlphaTo(float); |
| |
| template<typename ColorType, typename Functor> ColorType colorByModifingEachNonAlphaComponent(const ColorType&, Functor&&); |
| |
| template<typename ColorType> constexpr ColorType colorWithOverriddenAlpha(const ColorType&, uint8_t overrideAlpha); |
| template<typename ColorType> ColorType colorWithOverriddenAlpha(const ColorType&, float overrideAlpha); |
| |
| template<typename ColorType> constexpr ColorType invertedColorWithOverriddenAlpha(const ColorType&, uint8_t overrideAlpha); |
| template<typename ColorType> ColorType invertedColorWithOverriddenAlpha(const ColorType&, float overrideAlpha); |
| |
| template<typename ColorType, typename std::enable_if_t<std::is_same_v<typename ColorType::Model, RGBModel<typename ColorType::ComponentType>>>* = nullptr> constexpr bool isBlack(const ColorType&); |
| template<WhitePoint W> constexpr bool isBlack(const XYZA<float, W>&); |
| constexpr bool isBlack(const LCHA<float>&); |
| constexpr bool isBlack(const Lab<float>&); |
| |
| template<typename ColorType, typename std::enable_if_t<std::is_same_v<typename ColorType::Model, RGBModel<typename ColorType::ComponentType>>>* = nullptr> constexpr bool isWhite(const ColorType&); |
| template<WhitePoint W> constexpr bool isWhite(const XYZA<float, W>&); |
| constexpr bool isWhite(const LCHA<float>&); |
| constexpr bool isWhite(const Lab<float>&); |
| |
| constexpr uint16_t fastMultiplyBy255(uint16_t); |
| constexpr uint16_t fastDivideBy255(uint16_t); |
| |
| |
| inline uint8_t convertPrescaledSRGBAFloatToSRGBAByte(float value) |
| { |
| return std::clamp(std::lround(value), 0l, 255l); |
| } |
| |
| template<> constexpr uint8_t convertByteAlphaTo<uint8_t>(uint8_t value) |
| { |
| return value; |
| } |
| |
| template<> constexpr float convertByteAlphaTo<float>(uint8_t value) |
| { |
| return value / 255.0f; |
| } |
| |
| template<> inline uint8_t convertFloatAlphaTo<uint8_t>(float value) |
| { |
| return std::clamp(std::lround(value * 255.0f), 0l, 255l); |
| } |
| |
| template<> inline float convertFloatAlphaTo<float>(float value) |
| { |
| return clampedAlpha(value); |
| } |
| |
| template<typename ColorType, typename Functor> ColorType colorByModifingEachNonAlphaComponent(const ColorType& color, Functor&& functor) |
| { |
| auto components = asColorComponents(color); |
| auto copy = components; |
| copy[0] = std::invoke(functor, components[0]); |
| copy[1] = std::invoke(functor, components[1]); |
| copy[2] = std::invoke(std::forward<Functor>(functor), components[2]); |
| return { copy[0], copy[1], copy[2], copy[3] }; |
| } |
| |
| template<typename ColorType> constexpr ColorType colorWithOverriddenAlpha(const ColorType& color, uint8_t overrideAlpha) |
| { |
| auto copy = color; |
| copy.alpha = convertByteAlphaTo<typename ColorType::ComponentType>(overrideAlpha); |
| return copy; |
| } |
| |
| template<typename ColorType> ColorType colorWithOverriddenAlpha(const ColorType& color, float overrideAlpha) |
| { |
| auto copy = color; |
| copy.alpha = convertFloatAlphaTo<typename ColorType::ComponentType>(overrideAlpha); |
| return copy; |
| } |
| |
| template<typename ColorType> constexpr ColorType invertedColorWithOverriddenAlpha(const ColorType& color, uint8_t overrideAlpha) |
| { |
| static_assert(ColorType::Model::isInvertible); |
| |
| auto components = asColorComponents(color); |
| auto copy = components; |
| |
| for (unsigned i = 0; i < 3; ++i) |
| copy[i] = ColorType::Model::componentInfo[i].max - components[i]; |
| copy[3] = convertByteAlphaTo<typename ColorType::ComponentType>(overrideAlpha); |
| |
| return makeFromComponents<ColorType>(copy); |
| } |
| |
| template<typename ColorType> ColorType invertedColorWithOverriddenAlpha(const ColorType& color, float overrideAlpha) |
| { |
| static_assert(ColorType::Model::isInvertible); |
| |
| auto components = asColorComponents(color); |
| auto copy = components; |
| |
| for (unsigned i = 0; i < 3; ++i) |
| copy[i] = ColorType::Model::componentInfo[i].max - components[i]; |
| copy[3] = convertFloatAlphaTo<typename ColorType::ComponentType>(overrideAlpha); |
| |
| return makeFromComponents<ColorType>(copy); |
| } |
| |
| template<WhitePoint W> constexpr bool isBlack(const XYZA<float, W>& color) |
| { |
| return color.y == 0 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| constexpr bool isBlack(const LCHA<float>& color) |
| { |
| return color.lightness == 0 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| constexpr bool isBlack(const Lab<float>& color) |
| { |
| return color.lightness == 0 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| template<typename ColorType, typename std::enable_if_t<std::is_same_v<typename ColorType::Model, RGBModel<typename ColorType::ComponentType>>>*> |
| constexpr bool isBlack(const ColorType& color) |
| { |
| auto [c1, c2, c3, alpha] = color; |
| constexpr auto componentInfo = ColorType::Model::componentInfo; |
| return c1 == componentInfo[0].min && c2 == componentInfo[1].min && c3 == componentInfo[2].min && alpha == AlphaTraits<typename ColorType::ComponentType>::opaque; |
| } |
| |
| template<WhitePoint W> constexpr bool isWhite(const XYZA<float, W>& color) |
| { |
| return color.y == 1 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| constexpr bool isWhite(const LCHA<float>& color) |
| { |
| return color.lightness == 100 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| constexpr bool isWhite(const Lab<float>& color) |
| { |
| return color.lightness == 100 && color.alpha == AlphaTraits<float>::opaque; |
| } |
| |
| template<typename ColorType, typename std::enable_if_t<std::is_same_v<typename ColorType::Model, RGBModel<typename ColorType::ComponentType>>>*> |
| constexpr bool isWhite(const ColorType& color) |
| { |
| auto [c1, c2, c3, alpha] = color; |
| constexpr auto componentInfo = ColorType::Model::componentInfo; |
| return c1 == componentInfo[0].max && c2 == componentInfo[1].max && c3 == componentInfo[2].max && alpha == AlphaTraits<typename ColorType::ComponentType>::opaque; |
| } |
| |
| constexpr uint16_t fastMultiplyBy255(uint16_t value) |
| { |
| return (value << 8) - value; |
| } |
| |
| constexpr uint16_t fastDivideBy255(uint16_t value) |
| { |
| // While this is an approximate algorithm for division by 255, it gives perfectly accurate results for 16-bit values. |
| // FIXME: Since this gives accurate results for 16-bit values, we should get this optimization into compilers like clang. |
| uint16_t approximation = value >> 8; |
| uint16_t remainder = value - (approximation * 255) + 1; |
| return approximation + (remainder >> 8); |
| } |
| |
| } // namespace WebCore |