magnum/src/Color.h

#ifndef Magnum_Color_h
#define Magnum_Color_h
/*
    This file is part of Magnum.

    Copyright © 2010, 2011, 2012, 2013 Vladimír Vondruš <mosra@centrum.cz>

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included
    in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
    THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.
*/

/** @file
 * @brief Class Magnum::BasicColor3, Magnum::BasicColor4, typedef Magnum::Color3, Magnum::Color4
 */

#include <tuple>

#include "Math/Functions.h"
#include "Math/Vector4.h"
#include "Magnum.h"

namespace Magnum {

namespace Implementation {

/* Convert color from HSV */
template<class T> typename std::enable_if<std::is_floating_point<T>::value, BasicColor3<T>>::type fromHSV(typename BasicColor3<T>::HSV hsv) {
    Math::Deg<T> hue;
    T saturation, value;
    std::tie(hue, saturation, value) = hsv;

    /* Remove repeats */
    hue -= int(T(hue)/T(360))*Math::Deg<T>(360);
    if(hue < Math::Deg<T>(0)) hue += Math::Deg<T>(360);

    int h = int(T(hue)/T(60)) % 6;
    T f = T(hue)/T(60) - h;

    T p = value * (T(1) - saturation);
    T q = value * (T(1) - f*saturation);
    T t = value * (T(1) - (T(1) - f)*saturation);

    switch(h) {
        case 0: return {value, t, p};
        case 1: return {q, value, p};
        case 2: return {p, value, t};
        case 3: return {p, q, value};
        case 4: return {t, p, value};
        case 5: return {value, p, q};
        default: CORRADE_ASSERT_UNREACHABLE();
    }
}
template<class T> inline typename std::enable_if<std::is_integral<T>::value, BasicColor3<T>>::type fromHSV(typename BasicColor3<T>::HSV hsv) {
    return Math::denormalize<BasicColor3<T>>(fromHSV<typename BasicColor3<T>::FloatingPointType>(hsv));
}

/* Internal hue computing function */
template<class T> Math::Deg<T> hue(const BasicColor3<T>& color, T max, T delta) {
    T deltaInv60 = T(60)/delta;

    T hue(0);
    if(delta != T(0)) {
        if(max == color.r())
            hue = (color.g()-color.b())*deltaInv60 + (color.g() < color.b() ? T(360) : T(0));
        else if(max == color.g())
            hue = (color.b()-color.r())*deltaInv60 + T(120);
        else /* max == color.b() */
            hue = (color.r()-color.g())*deltaInv60 + T(240);
    }

    return Math::Deg<T>(hue);
}

/* Hue, saturation, value for floating-point types */
template<class T> inline Math::Deg<T> hue(typename std::enable_if<std::is_floating_point<T>::value, const BasicColor3<T>&>::type color) {
    T max = color.max();
    T delta = max - color.min();
    return hue(color, max, delta);
}
template<class T> inline T saturation(typename std::enable_if<std::is_floating_point<T>::value, const BasicColor3<T>&>::type color) {
    T max = color.max();
    T delta = max - color.min();
    return max != T(0) ? delta/max : T(0);
}
template<class T> inline T value(typename std::enable_if<std::is_floating_point<T>::value, const BasicColor3<T>&>::type color) {
    return color.max();
}

/* Hue, saturation, value for integral types */
template<class T> inline Math::Deg<typename BasicColor3<T>::FloatingPointType> hue(typename std::enable_if<std::is_integral<T>::value, const BasicColor3<T>&>::type color) {
    return hue<typename BasicColor3<T>::FloatingPointType>(Math::normalize<BasicColor3<typename BasicColor3<T>::FloatingPointType>>(color));
}
template<class T> inline typename BasicColor3<T>::FloatingPointType saturation(typename std::enable_if<std::is_integral<T>::value, const BasicColor3<T>&>::type& color) {
    return saturation<typename BasicColor3<T>::FloatingPointType>(Math::normalize<BasicColor3<typename BasicColor3<T>::FloatingPointType>>(color));
}
template<class T> inline typename BasicColor3<T>::FloatingPointType value(typename std::enable_if<std::is_integral<T>::value, const BasicColor3<T>&>::type color) {
    return Math::normalize<typename BasicColor3<T>::FloatingPointType>(color.max());
}

/* Convert color to HSV */
template<class T> inline typename BasicColor3<T>::HSV toHSV(typename std::enable_if<std::is_floating_point<T>::value, const BasicColor3<T>&>::type color) {
    T max = color.max();
    T delta = max - color.min();

    return typename BasicColor3<T>::HSV(hue<typename BasicColor3<T>::FloatingPointType>(color, max, delta), max != T(0) ? delta/max : T(0), max);
}
template<class T> inline typename BasicColor3<T>::HSV toHSV(typename std::enable_if<std::is_integral<T>::value, const BasicColor3<T>&>::type color) {
    return toHSV<typename BasicColor3<T>::FloatingPointType>(Math::normalize<BasicColor3<typename BasicColor3<T>::FloatingPointType>>(color));
}

/* Default alpha value */
template<class T> inline constexpr typename std::enable_if<std::is_floating_point<T>::value, T>::type defaultAlpha() {
    return T(1);
}
template<class T> inline constexpr typename std::enable_if<std::is_integral<T>::value, T>::type defaultAlpha() {
    return std::numeric_limits<T>::max();
}

}

/**
@brief Three-component (RGB) color

The class can store both floating-point (normalized) and integral
(denormalized) representation of color. You can convert between these two
representations using fromNormalized() and fromDenormalized().

Conversion from and to HSV is done always using floating-point types, so hue
is always in range in range @f$ [0.0, 360.0] @f$, saturation and value in
range @f$ [0.0, 1.0] @f$.

@see @ref Color3, @ref BasicColor4
*/
/* Not using template specialization because some internal functions are
   impossible to explicitly instantiate */
template<class T> class BasicColor3: public Math::Vector3<T> {
    public:
        /** @brief Corresponding floating-point type for HSV computation */
        typedef typename Math::TypeTraits<T>::FloatingPointType FloatingPointType;

        /**
         * @brief Type for storing HSV values
         *
         * Hue in range @f$ [0.0, 360.0] @f$, saturation and value in
         * range @f$ [0.0, 1.0] @f$.
         */
        typedef std::tuple<Math::Deg<FloatingPointType>, FloatingPointType, FloatingPointType> HSV;

        /**
         * @brief Create RGB color from HSV representation
         * @param hsv Hue, saturation and value
         *
         * Hue can overflow the range @f$ [0.0, 360.0] @f$.
         */
        constexpr static BasicColor3<T> fromHSV(HSV hsv) {
            return Implementation::fromHSV<T>(hsv);
        }
        /** @overload */
        constexpr static BasicColor3<T> fromHSV(Math::Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value) {
            return fromHSV(std::make_tuple(hue, saturation, value));
        }

        /**
         * @brief Default constructor
         *
         * All components are set to zero.
         */
        constexpr /*implicit*/ BasicColor3() {}

        /**
         * @brief Gray constructor
         * @param rgb   RGB value
         */
        constexpr explicit BasicColor3(T rgb): Math::Vector3<T>(rgb) {}

        /**
         * @brief Constructor
         * @param r     R value
         * @param g     G value
         * @param b     B value
         */
        constexpr /*implicit*/ BasicColor3(T r, T g, T b): Math::Vector3<T>(r, g, b) {}

        /** @copydoc Math::Vector::Vector(const Vector<size, U>&) */
        template<class U> constexpr explicit BasicColor3(const Math::Vector<3, U>& other): Math::Vector3<T>(other) {}

        /** @brief Copy constructor */
        constexpr BasicColor3(const Math::Vector<3, T>& other): Math::Vector3<T>(other) {}

        /**
         * @brief Convert to HSV
         *
         * Example usage:
         * @code
         * T hue, saturation, value;
         * std::tie(hue, saturation, value) = color.toHSV();
         * @endcode
         *
         * @see hue(), saturation(), value(), fromHSV()
         */
        constexpr HSV toHSV() const {
            return Implementation::toHSV<T>(*this);
        }

        /**
         * @brief Hue
         * @return Hue in range @f$ [0.0, 360.0] @f$.
         *
         * @see saturation(), value(), toHSV(), fromHSV()
         */
        constexpr Math::Deg<FloatingPointType> hue() const {
            return Math::Deg<FloatingPointType>(Implementation::hue<T>(*this));
        }

        /**
         * @brief Saturation
         * @return Saturation in range @f$ [0.0, 1.0] @f$.
         *
         * @see hue(), value(), toHSV(), fromHSV()
         */
        constexpr FloatingPointType saturation() const {
            return Implementation::saturation<T>(*this);
        }

        /**
         * @brief Value
         * @return Value in range @f$ [0.0, 1.0] @f$.
         *
         * @see hue(), saturation(), toHSV(), fromHSV()
         */
        constexpr FloatingPointType value() const {
            return Implementation::value<T>(*this);
        }

        MAGNUM_VECTOR_SUBCLASS_IMPLEMENTATION(3, BasicColor3)
};

/** @brief Three-component (RGB) float color */
typedef BasicColor3<Float> Color3;

MAGNUM_VECTORn_OPERATOR_IMPLEMENTATION(3, BasicColor3)

/**
@brief Four-component (RGBA) color

See @ref BasicColor3 for more information.
@see @ref Color4
*/
/* Not using template specialization because some internal functions are
   impossible to explicitly instantiate */
#ifndef DOXYGEN_GENERATING_OUTPUT
template<class T>
#else
template<class T = Float>
#endif
class BasicColor4: public Math::Vector4<T> {
    public:
        /** @copydoc BasicColor3::FloatingPointType */
        typedef typename BasicColor3<T>::FloatingPointType FloatingPointType;

        /** @copydoc BasicColor3::HSV */
        typedef typename BasicColor3<T>::HSV HSV;

        /**
         * @copydoc BasicColor3::fromHSV()
         * @param a     Alpha value, defaults to 1.0 for floating-point types
         *      and maximum positive value for integral types.
         */
        constexpr static BasicColor4<T> fromHSV(HSV hsv, T a = Implementation::defaultAlpha<T>()) {
            return BasicColor4<T>(Implementation::fromHSV<T>(hsv), a);
        }
        /** @overload */
        constexpr static BasicColor4<T> fromHSV(Math::Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value, T alpha) {
            return fromHSV(std::make_tuple(hue, saturation, value), alpha);
        }

        /**
         * @brief Default constructor
         *
         * RGB components are set to zero, A component is set to 1.0 for
         * floating-point types and maximum positive value for integral types.
         */
        constexpr /*implicit*/ BasicColor4(): Math::Vector4<T>(T(0), T(0), T(0), Implementation::defaultAlpha<T>()) {}

        /**
         * @copydoc BasicColor3::BasicColor3(T)
         * @param alpha Alpha value, defaults to 1.0 for floating-point types
         *      and maximum positive value for integral types.
         */
        constexpr explicit BasicColor4(T rgb, T alpha = Implementation::defaultAlpha<T>()): Math::Vector4<T>(rgb, rgb, rgb, alpha) {}

        /**
         * @brief Constructor
         * @param r     R value
         * @param g     G value
         * @param b     B value
         * @param a     A value, defaults to 1.0 for floating-point types and
         *      maximum positive value for integral types.
         */
        constexpr /*implicit*/ BasicColor4(T r, T g, T b, T a = Implementation::defaultAlpha<T>()): Math::Vector4<T>(r, g, b, a) {}

        /**
         * @brief Constructor
         * @param rgb   Three-component color
         * @param a     A value
         */
        /* Not marked as explicit, because conversion from BasicColor3 to BasicColor4
           is fairly common, nearly always with A set to 1 */
        constexpr /*implicit*/ BasicColor4(const Math::Vector3<T>& rgb, T a = Implementation::defaultAlpha<T>()): Math::Vector4<T>(rgb[0], rgb[1], rgb[2], a) {}

        /** @copydoc Math::Vector::Vector(const Vector<size, U>&) */
        template<class U> constexpr explicit BasicColor4(const Math::Vector<4, U>& other): Math::Vector4<T>(other) {}

        /** @brief Copy constructor */
        constexpr BasicColor4(const Math::Vector<4, T>& other): Math::Vector4<T>(other) {}

        /** @copydoc BasicColor3::toHSV() */
        constexpr HSV toHSV() const {
            return Implementation::toHSV<T>(Math::Vector4<T>::rgb());
        }

        /** @copydoc BasicColor3::hue() */
        constexpr Math::Deg<FloatingPointType> hue() const {
            return Implementation::hue<T>(Math::Vector4<T>::rgb());
        }

        /** @copydoc BasicColor3::saturation() */
        constexpr FloatingPointType saturation() const {
            return Implementation::saturation<T>(Math::Vector4<T>::rgb());
        }

        /** @copydoc BasicColor3::value() */
        constexpr FloatingPointType value() const {
            return Implementation::value<T>(Math::Vector4<T>::rgb());
        }

        MAGNUM_VECTOR_SUBCLASS_IMPLEMENTATION(4, BasicColor4)
};

/** @brief Four-component (RGBA) float color */
typedef BasicColor4<Float> Color4;

MAGNUM_VECTORn_OPERATOR_IMPLEMENTATION(4, BasicColor4)

/** @debugoperator{Magnum::BasicColor3} */
template<class T> inline Debug operator<<(Debug debug, const BasicColor3<T>& value) {
    return debug << static_cast<const Math::Vector3<T>&>(value);
}

/** @debugoperator{Magnum::BasicColor4} */
template<class T> inline Debug operator<<(Debug debug, const BasicColor4<T>& value) {
    return debug << static_cast<const Math::Vector4<T>&>(value);
}

namespace Math { namespace Implementation {
    template<class T> struct TypeForSize<3, BasicColor3<T>> { typedef BasicColor3<T> Type; };
    template<class T> struct TypeForSize<3, BasicColor4<T>> { typedef BasicColor3<T> Type; };
    template<class T> struct TypeForSize<4, BasicColor3<T>> { typedef BasicColor4<T> Type; };
    template<class T> struct TypeForSize<4, BasicColor4<T>> { typedef BasicColor4<T> Type; };
}}

}

namespace Corrade { namespace Utility {
    /** @configurationvalue{Magnum::BasicColor3} */
    template<class T> struct ConfigurationValue<Magnum::BasicColor3<T>>: public ConfigurationValue<Magnum::Math::Vector<3, T>> {};

    /** @configurationvalue{Magnum::BasicColor4} */
    template<class T> struct ConfigurationValue<Magnum::BasicColor4<T>>: public ConfigurationValue<Magnum::Math::Vector<4, T>> {};
}}

#endif