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2539fd6a5c
Skia does not have built-in support for gradient transition hints. So instead of adding custom gradient painting, now we do the same thing as other engines and preprocess color stops by replacing transition hints with a bunch of points lying between adjacent color stops and calculated using non-linear formula from the spec. As a result we get visually close enough rendering we would get by applying spec-formula individually to each point of a gradient.
49 lines
1.3 KiB
C++
49 lines
1.3 KiB
C++
/*
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* Copyright (c) 2023, MacDue <macdue@dueutil.tech>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Math.h>
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#include <LibGfx/Color.h>
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#include <LibGfx/Size.h>
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namespace Gfx {
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struct ColorStop {
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Color color;
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float position = AK::NaN<float>;
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Optional<float> transition_hint = {};
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bool operator==(ColorStop const&) const = default;
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};
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float color_stop_step(ColorStop const& previous_stop, ColorStop const& next_stop, float position);
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class GradientLine;
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inline float normalized_gradient_angle_radians(float gradient_angle)
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{
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// Adjust angle so 0 degrees is bottom
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float real_angle = 90 - gradient_angle;
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return AK::to_radians(real_angle);
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}
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template<typename T>
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inline float calculate_gradient_length(Size<T> gradient_size, float sin_angle, float cos_angle)
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{
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return AK::fabs(static_cast<float>(gradient_size.height()) * sin_angle) + AK::fabs(static_cast<float>(gradient_size.width()) * cos_angle);
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}
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template<typename T>
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inline float calculate_gradient_length(Size<T> gradient_size, float gradient_angle)
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{
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float angle = normalized_gradient_angle_radians(gradient_angle);
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float sin_angle, cos_angle;
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AK::sincos(angle, sin_angle, cos_angle);
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return calculate_gradient_length(gradient_size, sin_angle, cos_angle);
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}
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}
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