ladybird/Libraries/LibWeb/CSS/StyleValues/CSSColorValue.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <andreas@ladybird.org>
 * Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
 * Copyright (c) 2021-2024, Sam Atkins <sam@ladybird.org>
 * Copyright (c) 2022-2023, MacDue <macdue@dueutil.tech>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "CSSColorValue.h"
#include <LibWeb/CSS/Serialize.h>
#include <LibWeb/CSS/StyleValues/AngleStyleValue.h>
#include <LibWeb/CSS/StyleValues/CSSMathValue.h>
#include <LibWeb/CSS/StyleValues/CSSRGB.h>
#include <LibWeb/CSS/StyleValues/NumberStyleValue.h>
#include <LibWeb/CSS/StyleValues/PercentageStyleValue.h>

namespace Web::CSS {

ValueComparingNonnullRefPtr<CSSColorValue> CSSColorValue::create_from_color(Color color)
{
    auto make_rgb_color = [](Color const& color) {
        return CSSRGB::create(
            NumberStyleValue::create(color.red()),
            NumberStyleValue::create(color.green()),
            NumberStyleValue::create(color.blue()),
            NumberStyleValue::create(color.alpha() / 255.0));
    };

    if (color.value() == 0) {
        static auto transparent = make_rgb_color(color);
        return transparent;
    }

    if (color == Color::from_rgb(0x000000)) {
        static auto black = make_rgb_color(color);
        return black;
    }

    if (color == Color::from_rgb(0xffffff)) {
        static auto white = make_rgb_color(color);
        return white;
    }

    return make_rgb_color(color);
}

Optional<float> CSSColorValue::resolve_hue(CSSStyleValue const& style_value)
{
    // <number> | <angle> | none
    auto normalized = [](double number) {
        return fmod(number, 360.0);
    };

    if (style_value.is_number())
        return normalized(style_value.as_number().number());

    if (style_value.is_angle())
        return normalized(style_value.as_angle().angle().to_degrees());

    if (style_value.is_math() && style_value.as_math().resolves_to_angle())
        return normalized(style_value.as_math().resolve_angle().value().to_degrees());

    if (style_value.is_keyword() && style_value.to_keyword() == Keyword::None)
        return 0;

    return {};
}

Optional<float> CSSColorValue::resolve_with_reference_value(CSSStyleValue const& style_value, float one_hundred_percent_value)
{
    // <percentage> | <number> | none
    auto normalize_percentage = [one_hundred_percent_value](Percentage const& percentage) {
        return static_cast<float>(percentage.as_fraction()) * one_hundred_percent_value;
    };

    if (style_value.is_percentage())
        return normalize_percentage(style_value.as_percentage().percentage());

    if (style_value.is_number())
        return style_value.as_number().number();

    if (style_value.is_math()) {
        auto const& calculated = style_value.as_math();
        if (calculated.resolves_to_number())
            return calculated.resolve_number().value();
        if (calculated.resolves_to_percentage())
            return normalize_percentage(calculated.resolve_percentage().value());
    }

    if (style_value.is_keyword() && style_value.to_keyword() == Keyword::None)
        return 0;

    return {};
}

Optional<float> CSSColorValue::resolve_alpha(CSSStyleValue const& style_value)
{
    // <number> | <percentage> | none
    auto normalized = [](double number) {
        return clamp(number, 0.0, 1.0);
    };

    if (style_value.is_number())
        return normalized(style_value.as_number().number());

    if (style_value.is_percentage())
        return normalized(style_value.as_percentage().percentage().as_fraction());

    if (style_value.is_math()) {
        auto const& calculated = style_value.as_math();
        if (calculated.resolves_to_number())
            return normalized(calculated.resolve_number().value());
        if (calculated.resolves_to_percentage())
            return normalized(calculated.resolve_percentage().value().as_fraction());
    }

    if (style_value.is_keyword() && style_value.to_keyword() == Keyword::None)
        return 0;

    return {};
}

}