color.hpp

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/*
 Copyright (c) 2026 ETIB Corporation
 
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 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 */
 
#pragma once
 
#include <algorithm>
#include <cstdint>
#include <ostream>
#include <stdexcept>
#include <type_traits>
#include <utility>
 
namespace utility::graphic
{
 
    template<typename Type>
    concept CanBeColorComponent = std::is_arithmetic<Type>::value
        && (std::is_floating_point<Type>::value
            || std::is_integral<Type>::value);
 
    template<CanBeColorComponent Type> class Color
    {
        private:
        protected:
        Type _red;
 
        Type _green;
 
        Type _blue;
 
        Type _alpha;
 
        static Type clamp(Type value)
        {
            if constexpr (std::is_floating_point<Type>::value) {
                return (std::max)(Type { 0 }, (std::min)(Type { 1 }, value));
            } else {
                return (std::max)(Type { 0 }, (std::min)(Type { 255 }, value));
            }
        }
 
        static Type clampWide(long long value)
        {
            if constexpr (std::is_floating_point<Type>::value) {
                return clamp(static_cast<Type>(value));
            } else {
                constexpr long long max = 255;
                return static_cast<Type>(
                    (std::max)(0LL, (std::min)(max, value)));
            }
        }
 
        static constexpr Type maxValue()
        {
            if constexpr (std::is_floating_point<Type>::value) {
                return Type { 1 };
            } else {
                return Type { 255 };
            }
        }
 
        public:
        Color(void)
            : _red(Type {})
            , _green(Type {})
            , _blue(Type {})
            , _alpha(maxValue())
        {
        }
 
        Color(Type red, Type green, Type blue)
            : _red(clamp(red))
            , _green(clamp(green))
            , _blue(clamp(blue))
            , _alpha(maxValue())
        {
        }
 
        Color(Type red, Type green, Type blue, Type alpha)
            : _red(clamp(red))
            , _green(clamp(green))
            , _blue(clamp(blue))
            , _alpha(clamp(alpha))
        {
        }
 
        Color(const Color &other)
            : _red(other._red)
            , _green(other._green)
            , _blue(other._blue)
            , _alpha(other._alpha)
        {
        }
 
        Color(Color &&other) noexcept
            : _red(std::move(other._red))
            , _green(std::move(other._green))
            , _blue(std::move(other._blue))
            , _alpha(std::move(other._alpha))
        {
        }
 
        Color &operator=(const Color &other)
        {
            if (this != &other) {
                _red   = other._red;
                _green = other._green;
                _blue  = other._blue;
                _alpha = other._alpha;
            }
            return *this;
        }
 
        Color &operator=(Color &&other) noexcept
        {
            if (this != &other) {
                _red   = std::move(other._red);
                _green = std::move(other._green);
                _blue  = std::move(other._blue);
                _alpha = std::move(other._alpha);
            }
            return *this;
        }
 
        // Destructor
        ~Color(void) = default;
 
        void setRed(Type red)
        {
            _red = clamp(red);
        }
 
        Type getRed(void) const
        {
            return _red;
        }
 
        void setGreen(Type green)
        {
            _green = clamp(green);
        }
 
        Type getGreen(void) const
        {
            return _green;
        }
 
        void setBlue(Type blue)
        {
            _blue = clamp(blue);
        }
 
        Type getBlue(void) const
        {
            return _blue;
        }
 
        void setAlpha(Type alpha)
        {
            _alpha = clamp(alpha);
        }
 
        Type getAlpha(void) const
        {
            return _alpha;
        }
 
        void setRGBA(Type red, Type green, Type blue, Type alpha)
        {
            _red   = clamp(red);
            _green = clamp(green);
            _blue  = clamp(blue);
            _alpha = clamp(alpha);
        }
 
        bool operator==(const Color &other) const
        {
            return _red == other._red && _green == other._green
                && _blue == other._blue && _alpha == other._alpha;
        }
 
        bool operator!=(const Color &other) const
        {
            return !(*this == other);
        }
 
        Color operator+(const Color &other) const
        {
            return Color(
                clampWide(static_cast<long long>(_red) + other._red),
                clampWide(static_cast<long long>(_green) + other._green),
                clampWide(static_cast<long long>(_blue) + other._blue), _alpha);
        }
 
        Color operator-(const Color &other) const
        {
            return Color(
                clampWide(static_cast<long long>(_red) - other._red),
                clampWide(static_cast<long long>(_green) - other._green),
                clampWide(static_cast<long long>(_blue) - other._blue), _alpha);
        }
 
        Color operator*(Type scalar) const
        {
            return Color(clampWide(static_cast<long long>(_red) * scalar),
                         clampWide(static_cast<long long>(_green) * scalar),
                         clampWide(static_cast<long long>(_blue) * scalar),
                         _alpha);
        }
 
        Color grayscale(void) const
        {
            Type luminance;
            if constexpr (std::is_floating_point<Type>::value) {
                luminance =
                    clamp(Type { 0.299 } * _red + Type { 0.587 } * _green
                          + Type { 0.114 } * _blue);
            } else {
                luminance =
                    clamp((299 * _red + 587 * _green + 114 * _blue) / 1000);
            }
            return Color(luminance, luminance, luminance, _alpha);
        }
 
        Color inverted(void) const
        {
            return Color(maxValue() - _red, maxValue() - _green,
                         maxValue() - _blue, _alpha);
        }
 
        Color lerp(const Color &other, Type t) const
        {
            t              = clamp(t);
            Type oneMinusT = maxValue() - t;
 
            if constexpr (std::is_floating_point<Type>::value) {
                return Color(oneMinusT * _red + t * other._red,
                             oneMinusT * _green + t * other._green,
                             oneMinusT * _blue + t * other._blue,
                             oneMinusT * _alpha + t * other._alpha);
            } else {
                return Color(
                    clamp((oneMinusT * _red + t * other._red) / maxValue()),
                    clamp((oneMinusT * _green + t * other._green) / maxValue()),
                    clamp((oneMinusT * _blue + t * other._blue) / maxValue()),
                    clamp((oneMinusT * _alpha + t * other._alpha)
                          / maxValue()));
            }
        }
 
        Color blendOver(const Color &background) const
        {
            if constexpr (std::is_floating_point<Type>::value) {
                Type a         = _alpha;
                Type oneMinusA = Type { 1 } - a;
                return Color(a * _red + oneMinusA * background._red,
                             a * _green + oneMinusA * background._green,
                             a * _blue + oneMinusA * background._blue,
                             a + oneMinusA * background._alpha);
            } else {
                Type a         = _alpha;
                Type oneMinusA = maxValue() - a;
                return Color(
                    clamp((a * _red + oneMinusA * background._red)
                          / maxValue()),
                    clamp((a * _green + oneMinusA * background._green)
                          / maxValue()),
                    clamp((a * _blue + oneMinusA * background._blue)
                          / maxValue()),
                    clamp((a + oneMinusA * background._alpha) / maxValue()));
            }
        }
 
        Color lighter(Type factor) const
        {
            factor = clamp(factor);
            return lerp(Color(maxValue(), maxValue(), maxValue(), _alpha),
                        factor);
        }
 
        Color darker(Type factor) const
        {
            factor = clamp(factor);
            return lerp(Color(Type {}, Type {}, Type {}, _alpha), factor);
        }
 
        Color withAlpha(Type alpha) const
        {
            return Color(_red, _green, _blue, alpha);
        }
 
        bool isOpaque(void) const
        {
            return _alpha == maxValue();
        }
 
        bool isTransparent(void) const
        {
            return _alpha == Type {};
        }
 
        double alpha01(void) const
        {
            return static_cast<double>(_alpha)
                / static_cast<double>(maxValue());
        }
 
        bool operator<(const Color &other) const
        {
            if (_red != other._red) {
                return _red < other._red;
            }
            if (_green != other._green) {
                return _green < other._green;
            }
            if (_blue != other._blue) {
                return _blue < other._blue;
            }
            if (_alpha != other._alpha) {
                return _alpha < other._alpha;
            }
            return false;
        }
    };
 
    using Color32Bit = Color<std::uint8_t>;
 
    using ColorFloat = Color<float>;
 
    using ColorDouble = Color<double>;
 
    std::ostream &operator<<(std::ostream &stream, const Color32Bit &color);
 
    std::ostream &operator<<(std::ostream &stream, const ColorFloat &color);
 
    std::ostream &operator<<(std::ostream &stream, const ColorDouble &color);
 
}    // namespace utility::graphic