template<class T>
Magnum::Math::Color3 class

Color in linear RGB color space.

Contents

The class can store either floating-point (normalized) or integral (denormalized) representation of linear RGB color. Colors in sRGB color space should not be used directly in calculations — they should be converted to linear RGB using fromSrgb(), calculation done on the linear representation and then converted back to sRGB using toSrgb().

Note that constructor conversion between different types (like in Vector classes) doesn't do any (de)normalization, you should use pack) and unpack() instead, for example:

Color3 a{1.0f, 0.5f, 0.75f};
auto b = pack<Color3ub>(a); // b == {255, 127, 191}

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

Base classes

template<class T>
class Vector3
Three-component vector.

Public types

using FloatingPointType = TypeTraits<T>::FloatingPointType
Corresponding floating-point type.
using Hsv = std::tuple<Deg<FloatingPointType>, FloatingPointType, FloatingPointType>
Type for storing HSV color space values.
using HSV = Hsv deprecated
Type for storing HSV color space values.

Public static functions

static auto red(T red = Implementation::fullChannel<T>()) -> Color3<T> constexpr
Red color.
static auto green(T green = Implementation::fullChannel<T>()) -> Color3<T> constexpr
Green color.
static auto blue(T blue = Implementation::fullChannel<T>()) -> Color3<T> constexpr
Blue color.
static auto cyan(T red = T(0)) -> Color3<T> constexpr
Cyan color.
static auto magenta(T green = T(0)) -> Color3<T> constexpr
Magenta color.
static auto yellow(T blue = T(0)) -> Color3<T> constexpr
Yellow color.
static auto fromHsv(const Hsv& hsv) -> Color3<T>
Create RGB color from HSV representation.
static auto fromHsv(Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value) -> Color3<T>
static auto fromHSV(const Hsv& hsv) -> Color3<T> deprecated
Create RGB color from HSV representation.
static auto fromHSV(Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value) -> Color3<T> deprecated
static auto fromSrgb(const Vector3<FloatingPointType>& srgb) -> Color3<T>
Create linear RGB color from sRGB representation.
template<class Integral>
static auto fromSrgb(const Vector3<Integral>& srgb) -> Color3<T>
Create linear RGB color from integral sRGB representation.
static auto fromXyz(const Vector3<FloatingPointType>& xyz) -> Color3<T>
Create RGB color from CIE XYZ representation.

Constructors, destructors, conversion operators

Color3(ZeroInitT = ZeroInit) constexpr noexcept
Default constructor.
Color3(NoInitT) explicit noexcept
Construct vector without initializing the contents.

Color3(T rgb) explicit constexpr noexcept
Gray constructor.
Color3(T r, T g, T b) constexpr noexcept
Constructor.
template<class U>
Color3(const Vector<3, U>& other) explicit constexpr noexcept
Construct vector from another of different type.
template<class U, class V = decltype(Implementation::VectorConverter<3, T, U>::from(std::declval<U>()))>
Color3(const U& other) explicit constexpr
Construct color from external representation.
Color3(const Vector<3, T>& other) constexpr noexcept
Copy constructor.

Public functions

auto toHsv() const -> Hsv
Convert to HSV representation.
auto toHSV() const -> Hsv deprecated
Convert to HSV representation.
auto hue() const -> Deg<FloatingPointType>
Hue.
auto saturation() const -> FloatingPointType
Saturation.
auto value() const -> FloatingPointType
Value.
auto toSrgb() const -> Vector3<FloatingPointType>
Convert to sRGB representation.
template<class Integral>
auto toSrgb() const -> Vector3<Integral>
Convert to integral sRGB representation.
auto toXyz() const -> Vector3<FloatingPointType>
Convert to CIE XYZ representation.

Typedef documentation

template<class T>
typedef TypeTraits<T>::FloatingPointType Magnum::Math::Color3<T>::FloatingPointType

Corresponding floating-point type.

For HSV and other color spaces.

template<class T>
typedef std::tuple<Deg<FloatingPointType>, FloatingPointType, FloatingPointType> Magnum::Math::Color3<T>::Hsv

Type for storing HSV color space values.

Hue in range $ [0.0, 360.0] $ , saturation and value in range $ [0.0, 1.0] $ .

template<class T>
typedef Hsv Magnum::Math::Color3<T>::HSV

Type for storing HSV color space values.

Function documentation

template<class T>
static Color3<T> Magnum::Math::Color3<T>::red(T red = Implementation::fullChannel<T>()) constexpr

Red color.

Convenience alternative to e.g. Color3{red, 0.0f, 0.0f}. With floating-point underlying type equivalent to Vector3::xAxis().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::green(T green = Implementation::fullChannel<T>()) constexpr

Green color.

Convenience alternative to e.g. Color3(0.0f, green, 0.0f). With floating-point underlying type equivalent to Vector3::yAxis().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::blue(T blue = Implementation::fullChannel<T>()) constexpr

Blue color.

Convenience alternative to e.g. Color3{0.0f, 0.0f, blue}. With floating-point underlying type equivalent to Vector3::zAxis().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::cyan(T red = T(0)) constexpr

Cyan color.

Convenience alternative to e.g. Color3{red, 1.0f, 1.0f}. With floating-point underlying type equivalent to Vector3::xScale().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::magenta(T green = T(0)) constexpr

Magenta color.

Convenience alternative to e.g. Color3{1.0f, green, 1.0f}. With floating-point underlying type equivalent to Vector3::yScale().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::yellow(T blue = T(0)) constexpr

Yellow color.

Convenience alternative to e.g. Color3{1.0f, 1.0f, yellow}. With floating-point underlying type equivalent to Vector3::zScale().

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromHsv(const Hsv& hsv)

Create RGB color from HSV representation.

Parameters
hsv Color in HSV color space

Hue can overflow the range $ [0.0, 360.0] $ .

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromHsv(Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromHSV(const Hsv& hsv)

Create RGB color from HSV representation.

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromHSV(Deg<FloatingPointType> hue, FloatingPointType saturation, FloatingPointType value)

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromSrgb(const Vector3<FloatingPointType>& srgb)

Create linear RGB color from sRGB representation.

Parameters
srgb Color in sRGB color space

Applies inverse sRGB curve onto input, returning the input in linear RGB color space with D65 illuminant and 2° standard colorimetric observer.

\[ \boldsymbol{c}_\mathrm{linear} = \begin{cases} \dfrac{\boldsymbol{c}_\mathrm{sRGB}}{12.92}, & \boldsymbol{c}_\mathrm{sRGB} \le 0.04045 \\ \left( \dfrac{\boldsymbol{c}_\mathrm{sRGB} + a}{1 + a} \right)^{2.4}, & \boldsymbol{c}_\mathrm{sRGB} > 0.04045 \end{cases} \]

template<class T> template<class Integral>
static Color3<T> Magnum::Math::Color3<T>::fromSrgb(const Vector3<Integral>& srgb)

Create linear RGB color from integral sRGB representation.

Parameters
srgb Color in sRGB color space

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Useful in cases where you have for example an 8-bit sRGB representation and want to create a floating-point linear RGB color out of it:

Math::Vector3<UnsignedByte> srgb;
auto rgb = Color3::fromSrgb(srgb);

template<class T>
static Color3<T> Magnum::Math::Color3<T>::fromXyz(const Vector3<FloatingPointType>& xyz)

Create RGB color from CIE XYZ representation.

Parameters
xyz Color in CIE XYZ color space

Applies transformation matrix, returning the input in linear RGB color space with D65 illuminant and 2° standard colorimetric observer.

\[ \begin{bmatrix} R_\mathrm{linear} \\ G_\mathrm{linear} \\ B_\mathrm{linear} \end{bmatrix} = \begin{bmatrix} 3.2406 & -1.5372 & -0.4986 \\ -0.9689 & 1.8758 & 0.0415 \\ 0.0557 & -0.2040 & 1.0570 \end{bmatrix} \begin{bmatrix} X \\ Y \\ Z \end{bmatrix} \]

template<class T>
Magnum::Math::Color3<T>::Color3(ZeroInitT = ZeroInit) constexpr noexcept

Default constructor.

All components are set to zero.

template<class T>
Magnum::Math::Color3<T>::Color3(T rgb) explicit constexpr noexcept

Gray constructor.

Parameters
rgb RGB value

template<class T>
Magnum::Math::Color3<T>::Color3(T r, T g, T b) constexpr noexcept

Constructor.

Parameters
r R value
g G value
b B value

template<class T> template<class U>
Magnum::Math::Color3<T>::Color3(const Vector<3, U>& other) explicit constexpr noexcept

Construct vector from another of different type.

Performs only default casting on the values, no rounding or anything else. Example usage:

Vector<4, Float> floatingPoint(1.3f, 2.7f, -15.0f, 7.0f);
Vector<4, Byte> integral(floatingPoint);
// integral == {1, 2, -15, 7}

template<class T>
Hsv Magnum::Math::Color3<T>::toHsv() const

Convert to HSV representation.

Example usage:

Deg hue;
Float saturation, value;
std::tie(hue, saturation, value) = color.toHsv();

template<class T>
Hsv Magnum::Math::Color3<T>::toHSV() const

Convert to HSV representation.

template<class T>
Deg<FloatingPointType> Magnum::Math::Color3<T>::hue() const

Hue.

Returns Hue in range $ [0.0, 360.0] $ .

template<class T>
FloatingPointType Magnum::Math::Color3<T>::saturation() const

Saturation.

Returns Saturation in range $ [0.0, 1.0] $ .

template<class T>
FloatingPointType Magnum::Math::Color3<T>::value() const

Value.

Returns Value in range $ [0.0, 1.0] $ .

template<class T>
Vector3<FloatingPointType> Magnum::Math::Color3<T>::toSrgb() const

Convert to sRGB representation.

Assuming the color is in linear RGB with D65 illuminant and 2° standard colorimetric observer, applies sRGB curve onto it, returning the color represented in sRGB color space:

\[ \boldsymbol{c}_\mathrm{sRGB} = \begin{cases} 12.92C_\mathrm{linear}, & \boldsymbol{c}_\mathrm{linear} \le 0.0031308 \\ (1 + a) \boldsymbol{c}_\mathrm{linear}^{1/2.4}-a, & \boldsymbol{c}_\mathrm{linear} > 0.0031308 \end{cases} \]

template<class T> template<class Integral>
Vector3<Integral> Magnum::Math::Color3<T>::toSrgb() const

Convert to integral sRGB representation.

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. Useful in cases where you have a floating-point linear RGB color and want to create for example an 8-bit sRGB representation out of it:

Color3 color;
Math::Vector3<UnsignedByte> srgb = color.toSrgb<UnsignedByte>();

template<class T>
Vector3<FloatingPointType> Magnum::Math::Color3<T>::toXyz() const

Convert to CIE XYZ representation.

Assuming the color is in linear RGB with D65 illuminant and 2° standard colorimetric observer, applies transformation matrix, returning the color in CIE XYZ color space.

\[ \begin{bmatrix} X \\ Y \\ Z \end{bmatrix} = \begin{bmatrix} 0.4124 & 0.3576 & 0.1805 \\ 0.2126 & 0.7152 & 0.0722 \\ 0.0193 & 0.1192 & 0.9505 \end{bmatrix} \begin{bmatrix} R_\mathrm{linear} \\ G_\mathrm{linear} \\ B_\mathrm{linear} \end{bmatrix} \]

Please note that x(), y() and z() do not correspond to primaries in CIE XYZ color space, but are rather aliases to r(), g() and b().

template<class T> template<class T>
Vector3<T> xyYToXyz(const Vector3<T>& xyY)

Convert color from CIE xyY representation to CIE XYZ.

\[ \begin{array}{rcl} X & = & \dfrac{Y}{y}x \\ Z & = & \dfrac{Y}{y}(1 - x - y) \end{array} \]

template<class T> template<class T>
Vector3<T> xyzToXyY(const Vector3<T>& xyz)

Convert color from CIE XYZ representation to CIE xyY.

\[ \begin{array}{rcl} x & = & \dfrac{X}{X + Y + Z} \\ y & = & \dfrac{Y}{X + Y + Z} \end{array} \]

template<class T>
Color3<UnsignedByte> operator"" _rgb(unsigned long long value) constexpr

8bit-per-channel linear RGB literal

Unpacks the literal into three 8-bit values. Example usage:

Color3ub a = 0x33b27f_rgb;  // {0x33, 0xb2, 0x7f}

template<class T>
Vector3<UnsignedByte> operator"" _srgb(unsigned long long value) constexpr

8bit-per-channel sRGB literal

Unpacks the literal into three 8-bit values without any colorspace conversion. Behaves identically to operator""_rgb() though it doesn't return a Color3 type to indicate that the resulting value is not linear RGB. Use this literal to document that given value is in sRGB. Example usage:

Math::Vector3<UnsignedByte> a = 0x33b27f_srgb;  // {0x33, 0xb2, 0x7f}

template<class T>
Color3<Float> operator"" _rgbf(unsigned long long value)

Float linear RGB literal.

Unpacks the 8-bit values into three floats. Example usage:

Color3 a = 0x33b27f_rgbf;   // {0.2f, 0.698039f, 0.498039f}

template<class T>
Color3<Float> operator"" _srgbf(unsigned long long value)

Float sRGB literal.

Unpacks the 8-bit values into three floats and converts the color space from sRGB to linear RGB. See Color3::fromSrgb() for more information. Example usage:

Color3 a = 0x33b27f_srgbf;  // {0.0331048f, 0.445201f, 0.212231f}

template<class T>
Corrade::Utility::Debug& operator<<(Corrade::Utility::Debug& debug, const Color3<UnsignedByte>& value)

Debug output operator.

Prints the value as hex color (e.g. #ff33aa). Other underlying types are handled by operator<<(Corrade::Utility::Debug&, const Vector<size, T>&).