| /* |
| * 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. |
| */ |
| |
| #include "config.h" |
| #include "ColorInterpolation.h" |
| |
| #include "Color.h" |
| |
| namespace WebCore { |
| |
| std::pair<float, float> fixupHueComponentsPriorToInterpolation(HueInterpolationMethod method, float component1, float component2) |
| { |
| auto normalizeAnglesUsingShorterAlgorithm = [] (auto theta1, auto theta2) -> std::pair<float, float> { |
| // https://drafts.csswg.org/css-color-4/#hue-shorter |
| auto difference = theta2 - theta1; |
| if (difference > 180.0) |
| return { theta1 + 360.0, theta2 }; |
| if (difference < -180.0) |
| return { theta1, theta2 + 360.0 }; |
| return { theta1, theta2 }; |
| }; |
| |
| auto normalizeAnglesUsingLongerAlgorithm = [] (auto theta1, auto theta2) -> std::pair<float, float> { |
| // https://drafts.csswg.org/css-color-4/#hue-longer |
| auto difference = theta2 - theta1; |
| if (difference > 0.0 && difference < 180.0) |
| return { theta1 + 360.0, theta2 }; |
| if (difference > -180.0 && difference < 0) |
| return { theta1, theta2 + 360.0 }; |
| return { theta1, theta2 }; |
| }; |
| |
| auto normalizeAnglesUsingIncreasingAlgorithm = [] (auto theta1, auto theta2) -> std::pair<float, float> { |
| // https://drafts.csswg.org/css-color-4/#hue-increasing |
| if (theta2 < theta1) |
| return { theta1, theta2 + 360.0 }; |
| return { theta1, theta2 }; |
| }; |
| |
| auto normalizeAnglesUsingDecreasingAlgorithm = [] (auto theta1, auto theta2) -> std::pair<float, float> { |
| // https://drafts.csswg.org/css-color-4/#hue-decreasing |
| if (theta1 < theta2) |
| return { theta1 + 360.0, theta2 }; |
| return { theta1, theta2 }; |
| }; |
| |
| auto normalizeAnglesUsingSpecifiedAlgorithm = [] (auto theta1, auto theta2) -> std::pair<float, float> { |
| // https://drafts.csswg.org/css-color-4/#hue-specified |
| return { theta1, theta2 }; |
| }; |
| |
| switch (method) { |
| case HueInterpolationMethod::Shorter: |
| return normalizeAnglesUsingShorterAlgorithm(component1, component2); |
| case HueInterpolationMethod::Longer: |
| return normalizeAnglesUsingLongerAlgorithm(component1, component2); |
| case HueInterpolationMethod::Increasing: |
| return normalizeAnglesUsingIncreasingAlgorithm(component1, component2); |
| case HueInterpolationMethod::Decreasing: |
| return normalizeAnglesUsingDecreasingAlgorithm(component1, component2); |
| case HueInterpolationMethod::Specified: |
| return normalizeAnglesUsingSpecifiedAlgorithm(component1, component2); |
| } |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| |
| Color interpolateColors(ColorInterpolationMethod colorInterpolationMethod, Color color1, double color1Multiplier, Color color2, double color2Multiplier) |
| { |
| return WTF::switchOn(colorInterpolationMethod.colorSpace, |
| [&] (auto& colorSpace) { |
| using ColorType = typename std::remove_reference_t<decltype(colorSpace)>::ColorType; |
| switch (colorInterpolationMethod.alphaPremultiplication) { |
| case AlphaPremultiplication::Premultiplied: |
| return makeCanonicalColor(interpolateColorComponents<AlphaPremultiplication::Premultiplied>(colorSpace, color1.toColorTypeLossy<ColorType>(), color1Multiplier, color2.toColorTypeLossy<ColorType>(), color2Multiplier)); |
| case AlphaPremultiplication::Unpremultiplied: |
| return makeCanonicalColor(interpolateColorComponents<AlphaPremultiplication::Unpremultiplied>(colorSpace, color1.toColorTypeLossy<ColorType>(), color1Multiplier, color2.toColorTypeLossy<ColorType>(), color2Multiplier)); |
| } |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| ); |
| } |
| |
| } |