| /* |
| * Copyright (C) 2021-2022 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 "AlphaPremultiplication.h" |
| #include "ColorInterpolationMethod.h" |
| #include "ColorNormalization.h" |
| #include "ColorTypes.h" |
| |
| namespace WebCore { |
| |
| class Color; |
| |
| template<AlphaPremultiplication, typename InterpolationMethodColorSpace> |
| typename InterpolationMethodColorSpace::ColorType interpolateColorComponents(InterpolationMethodColorSpace, typename InterpolationMethodColorSpace::ColorType color1, double color1Multiplier, typename InterpolationMethodColorSpace::ColorType color2, double color2Multiplier); |
| |
| Color interpolateColors(ColorInterpolationMethod, Color color1, double color1Multiplier, Color color2, double color2Multiplier); |
| |
| |
| // MARK: - Pre-interpolation normalization/fixup. |
| |
| std::pair<float, float> fixupHueComponentsPriorToInterpolation(HueInterpolationMethod, float component1, float component2); |
| |
| // MARK: - Premultiplication-agnostic interpolation helpers. |
| |
| inline float interpolateComponentWithoutAccountingForNaN(float componentFromColor1, double color1Multiplier, float componentFromColor2, double color2Multiplier) |
| { |
| return (componentFromColor1 * color1Multiplier) + (componentFromColor2 * color2Multiplier); |
| } |
| |
| inline float interpolateComponentAccountingForNaN(float componentFromColor1, double color1Multiplier, float componentFromColor2, double color2Multiplier) |
| { |
| if (std::isnan(componentFromColor1)) |
| return componentFromColor2; |
| if (std::isnan(componentFromColor2)) |
| return componentFromColor1; |
| |
| return interpolateComponentWithoutAccountingForNaN(componentFromColor1, color1Multiplier, componentFromColor2, color2Multiplier); |
| } |
| |
| template<typename InterpolationMethodColorSpace> |
| float interpolateHue(InterpolationMethodColorSpace interpolationMethodColorSpace, float componentFromColor1, double color1Multiplier, float componentFromColor2, double color2Multiplier) |
| { |
| if (std::isnan(componentFromColor1)) |
| return componentFromColor2; |
| if (std::isnan(componentFromColor2)) |
| return componentFromColor1; |
| |
| auto [fixedupComponent1, fixedupComponent2] = fixupHueComponentsPriorToInterpolation(interpolationMethodColorSpace.hueInterpolationMethod, componentFromColor1, componentFromColor2); |
| return interpolateComponentWithoutAccountingForNaN(fixedupComponent1, color1Multiplier, fixedupComponent2, color2Multiplier); |
| } |
| |
| // MARK: - Premultiplied interpolation. |
| |
| struct PremultipliedAlphaState { |
| float alphaForPremultiplicationOfColor1; |
| float alphaForPremultiplicationOfColor2; |
| float alphaForUnpremultiplication; |
| float resultAlpha; |
| }; |
| inline PremultipliedAlphaState interpolateAlphaPremulitplied(float alphaForColor1, double color1Multiplier, float alphaForColor2, double color2Multiplier) |
| { |
| // If both alpha channels are none/missing, no premultiplication is performed and the resulting color will have a none/missing alpha channel. |
| // If only one alpha channels is none/missing, the other alpha channel is used premultiplication of both colors and is the resulting color's alpha channel. |
| // If neither alpha channel is none/missing, each alpha channel is used for the premultiplication of its associated color and the interpolated result of the two alpha channels is the resulting color's alpha channel. |
| |
| if (std::isnan(alphaForColor1)) { |
| if (std::isnan(alphaForColor2)) |
| return { 1.0f, 1.0f, 1.0f, std::numeric_limits<float>::quiet_NaN() }; |
| return { alphaForColor2, alphaForColor2, alphaForColor2, alphaForColor2 }; |
| } |
| if (std::isnan(alphaForColor2)) |
| return { alphaForColor1, alphaForColor1, alphaForColor1, alphaForColor1 }; |
| |
| auto interpolatedAlpha = interpolateComponentWithoutAccountingForNaN(alphaForColor1, color1Multiplier, alphaForColor2, color2Multiplier); |
| return { alphaForColor1, alphaForColor2, interpolatedAlpha, interpolatedAlpha }; |
| } |
| |
| template<size_t I, typename InterpolationMethodColorSpace> |
| float interpolateComponentUsingPremultipliedAlpha(InterpolationMethodColorSpace interpolationMethodColorSpace, ColorComponents<float, 4> colorComponents1, double color1Multiplier, ColorComponents<float, 4> colorComponents2, double color2Multiplier, PremultipliedAlphaState interpolatedAlpha) |
| { |
| using ColorType = typename InterpolationMethodColorSpace::ColorType; |
| constexpr auto componentInfo = ColorType::Model::componentInfo; |
| |
| if constexpr (componentInfo[I].type == ColorComponentType::Angle) |
| return interpolateHue(interpolationMethodColorSpace, colorComponents1[I], color1Multiplier, colorComponents2[I], color2Multiplier); |
| else { |
| if (std::isnan(colorComponents1[I])) |
| return colorComponents2[I]; |
| if (std::isnan(colorComponents2[I])) |
| return colorComponents1[I]; |
| |
| auto premultipliedComponent1 = colorComponents1[I] * interpolatedAlpha.alphaForPremultiplicationOfColor1; |
| auto premultipliedComponent2 = colorComponents2[I] * interpolatedAlpha.alphaForPremultiplicationOfColor2; |
| |
| auto premultipliedResult = interpolateComponentWithoutAccountingForNaN(premultipliedComponent1, color1Multiplier, premultipliedComponent2, color2Multiplier); |
| |
| if (interpolatedAlpha.alphaForUnpremultiplication == 0.0f) |
| return premultipliedResult; |
| return premultipliedResult / interpolatedAlpha.alphaForUnpremultiplication; |
| } |
| } |
| |
| // MARK: - Unpremultiplied interpolation. |
| |
| inline float interpolateAlphaUnpremulitplied(float alphaForColor1, double color1Multiplier, float alphaForColor2, double color2Multiplier) |
| { |
| return interpolateComponentAccountingForNaN(alphaForColor1, color1Multiplier, alphaForColor2, color2Multiplier); |
| } |
| |
| template<size_t I, typename InterpolationMethodColorSpace> |
| float interpolateComponentUsingUnpremultipliedAlpha(InterpolationMethodColorSpace interpolationMethodColorSpace, ColorComponents<float, 4> colorComponents1, double color1Multiplier, ColorComponents<float, 4> colorComponents2, double color2Multiplier) |
| { |
| using ColorType = typename InterpolationMethodColorSpace::ColorType; |
| constexpr auto componentInfo = ColorType::Model::componentInfo; |
| |
| if constexpr (componentInfo[I].type == ColorComponentType::Angle) |
| return interpolateHue(interpolationMethodColorSpace, colorComponents1[I], color1Multiplier, colorComponents2[I], color2Multiplier); |
| else |
| return interpolateComponentAccountingForNaN(colorComponents1[I], color1Multiplier, colorComponents2[I], color2Multiplier); |
| } |
| |
| // MARK: - Interpolation. |
| |
| template<AlphaPremultiplication alphaPremultiplication, typename InterpolationMethodColorSpace> |
| typename InterpolationMethodColorSpace::ColorType interpolateColorComponents(InterpolationMethodColorSpace interpolationMethodColorSpace, typename InterpolationMethodColorSpace::ColorType color1, double color1Multiplier, typename InterpolationMethodColorSpace::ColorType color2, double color2Multiplier) |
| { |
| auto colorComponents1 = asColorComponents(color1.unresolved()); |
| auto colorComponents2 = asColorComponents(color2.unresolved()); |
| |
| if constexpr (alphaPremultiplication == AlphaPremultiplication::Premultiplied) { |
| auto interpolatedAlpha = interpolateAlphaPremulitplied(colorComponents1[3], color1Multiplier, colorComponents2[3], color2Multiplier); |
| auto interpolatedComponent1 = interpolateComponentUsingPremultipliedAlpha<0>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier, interpolatedAlpha); |
| auto interpolatedComponent2 = interpolateComponentUsingPremultipliedAlpha<1>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier, interpolatedAlpha); |
| auto interpolatedComponent3 = interpolateComponentUsingPremultipliedAlpha<2>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier, interpolatedAlpha); |
| |
| return makeColorTypeByNormalizingComponents<typename InterpolationMethodColorSpace::ColorType>({ interpolatedComponent1, interpolatedComponent2, interpolatedComponent3, interpolatedAlpha.resultAlpha }); |
| } else { |
| auto interpolatedAlpha = interpolateAlphaUnpremulitplied(colorComponents1[3], color1Multiplier, colorComponents2[3], color2Multiplier); |
| auto interpolatedComponent1 = interpolateComponentUsingUnpremultipliedAlpha<0>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier); |
| auto interpolatedComponent2 = interpolateComponentUsingUnpremultipliedAlpha<1>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier); |
| auto interpolatedComponent3 = interpolateComponentUsingUnpremultipliedAlpha<2>(interpolationMethodColorSpace, colorComponents1, color1Multiplier, colorComponents2, color2Multiplier); |
| |
| return makeColorTypeByNormalizingComponents<typename InterpolationMethodColorSpace::ColorType>({ interpolatedComponent1, interpolatedComponent2, interpolatedComponent3, interpolatedAlpha }); |
| } |
| } |
| |
| } |