Class Color

• Defined in File common.h

Inheritance Relationships

Base Type

• public Vector4f

Class Documentation

class Color : public Vector4f

Stores an RGBA floating point color value.

This class simply wraps around an Eigen::Vector4f, providing some convenient methods and terminology for thinking of it as a color. The data operates in the same way as Eigen::Vector4f, and the following values are identical:

Channel	Array Index	Eigen::Vector4f Value	Color Value
Red	0	x()	r()
Green	1	y()	g()
Blue	2	z()	b()
Alpha	3	w()	w()

Note

The method for the alpha component is always w().

You can and should still use the various convenience methods such as any(), all(), head<index>(), etc provided by Eigen.

Public Functions

Color()

Default constructor: represents black (r, g, b, a = 0)

Color(const Eigen::Vector4f &color)

Makes an exact copy of the data represented by the input parameter.

Parameters

• color: The four dimensional float vector being copied.

Color(const Eigen::Vector3f &color, float alpha)

Copies (x, y, z) from the input vector, and uses the value specified by the alpha parameter for this Color object’s alpha component.

Parameters

• color: The three dimensional float vector being copied.

• alpha: The value to set this object’s alpha component to.

Color(const Eigen::Vector3i &color, int alpha)

Copies (x, y, z) from the input vector, casted as floats first and then divided by 255.0, and uses the value specified by the alpha parameter, casted to a float and divided by 255.0 as well, for this Color object’s alpha component.

Parameters

• color: The three dimensional integer vector being copied, will be divided by 255.0.

• alpha: The value to set this object’s alpha component to, will be divided by 255.0.

Color(const Eigen::Vector3f &color)

Copies (x, y, z) from the input vector, and sets the alpha of this color to be 1.0.

Parameters

• color: The three dimensional float vector being copied.

Color(const Eigen::Vector3i &color)

Copies (x, y, z) from the input vector, casting to floats and dividing by 255.0. The alpha of this color will be set to 1.0.

Parameters

• color: The three dimensional integer vector being copied, will be divided by 255.0.

Color(const Eigen::Vector4i &color)

Copies (x, y, z, w) from the input vector, casting to floats and dividing by 255.0.

Parameters

• color: The three dimensional integer vector being copied, will be divided by 255.0.

Color(float intensity, float alpha)

Creates the Color (intensity, intensity, intensity, alpha).

Parameters

• intensity: The value to be used for red, green, and blue.

• alpha: The alpha component of the color.

Color(int intensity, int alpha)

Creates the Color (intensity, intensity, intensity, alpha) / 255.0. Values are casted to floats before division.

Parameters

• intensity: The value to be used for red, green, and blue, will be divided by 255.0.

• alpha: The alpha component of the color, will be divided by 255.0.

Color(float r, float g, float b, float a)

Explicit constructor: creates the Color (r, g, b, a).

Parameters

• r: The red component of the color.

• g: The green component of the color.

• b: The blue component of the color.

• a: The alpha component of the color.

Color(int r, int g, int b, int a)

Explicit constructor: creates the Color (r, g, b, a) / 255.0. Values are casted to floats before division.

Parameters

• r: The red component of the color, will be divided by 255.0.

• g: The green component of the color, will be divided by 255.0.

• b: The blue component of the color, will be divided by 255.0.

• a: The alpha component of the color, will be divided by 255.0.

template<typename Derived>
Color(const Eigen::MatrixBase<Derived> &p)

Construct a color vector from MatrixBase (needed to play nice with Eigen)

template<typename Derived>
Color &operator=(const Eigen::MatrixBase<Derived> &p)

Assign a color vector from MatrixBase (needed to play nice with Eigen)

float &r()

Return a reference to the red channel.

const float &r() const

Return a reference to the red channel (const version)

float &g()

Return a reference to the green channel.

const float &g() const

Return a reference to the green channel (const version)

float &b()

Return a reference to the blue channel.

const float &b() const

Return a reference to the blue channel (const version)

Color contrastingColor() const

Computes the luminance as l = 0.299r + 0.587g + 0.144b + 0.0a. If the luminance is less than 0.5, white is returned. If the luminance is greater than or equal to 0.5, black is returned. Both returns will have an alpha component of 1.0.

operator const NVGcolor&() const

Allows for conversion between this Color and NanoVG’s representation.

Allows for conversion between nanogui::Color and the NanoVG NVGcolor class.