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