Rgba Class Reference

Detailed Description

Defines RGBA (red, green, blue, alpha) values on the range [0, 1].

#include <drake/geometry/rgba.h>

Public Member Functions
	Rgba ()=default
	Default constructor produces fully opaque white.
	Rgba (double r, double g, double b, double a=1.0)
	Constructs with given (r, g, b, a) values.
double	r () const
	Red.
double	g () const
	Green.
double	b () const
	Blue.
double	a () const
	Alpha.
Eigen::Vector4d	rgba () const
	Returns all four elements in order.
void	set (double r, double g, double b, double a=1.0)
	Sets (r, g, b, a) values.
void	set (const Eigen::Ref< const Eigen::VectorXd > &rgba)
	Sets an (r, g, b, a) from a vector.
void	update (std::optional< double > r={}, std::optional< double > g={}, std::optional< double > b={}, std::optional< double > a={})
	Updates individual (r, g, b, a) values; any values not provided will remain unchanged.
bool	AlmostEqual (const Rgba &other, double tolerance=0.0) const
	Reports if two Rgba values are equal within a given absolute tolerance.
bool	operator== (const Rgba &other) const
bool	operator!= (const Rgba &other) const
Rgba	operator* (const Rgba &other) const
	Computes the element-wise product of two rgba colors.
Rgba	scale_rgb (double scale) const
	Computes a new Rgba color by multiplying the color channels (rgb) by the given scalar scalar.
std::string	to_string () const
	Converts the Rgba value to a string representation.
template<typename Archive>
void	Serialize (Archive *a)
	Passes this object to an Archive.
Implements CopyConstructible, CopyAssignable, MoveConstructible, MoveAssignable
	Rgba (const Rgba &)=default
Rgba &	operator= (const Rgba &)=default
	Rgba (Rgba &&)=default
Rgba &	operator= (Rgba &&)=default

Constructor & Destructor Documentation

Rgba() [1/4]

Rgba ( const Rgba & )

default

Rgba() [2/4]

Rgba ( Rgba && )

default

Rgba() [3/4]

Rgba ( )

default

Default constructor produces fully opaque white.

Rgba() [4/4]

Rgba	(	double	r,
		double	g,
		double	b,
		double	a = 1.0 )

Constructs with given (r, g, b, a) values.

Precondition

All values are within the range of [0, 1].

Member Function Documentation

a()

double a

(

)

const

Alpha.

AlmostEqual()

bool AlmostEqual	(	const Rgba &	other,
		double	tolerance = 0.0 ) const

Reports if two Rgba values are equal within a given absolute tolerance.

They are "equal" so long as the difference in no single channel is larger than the specified tolerance.

b()

double b

(

)

const

Blue.

g()

double g

(

)

const

Green.

operator!=()

bool operator!=

(

const Rgba &

other

)

const

operator*()

Rgba operator*

(

const Rgba &

other

)

const

Computes the element-wise product of two rgba colors.

This type of calculation is frequently used to modulate one color with another (e.g., for lighting or texturing).

operator=() [1/2]

Rgba & operator= ( const Rgba & )

default

operator=() [2/2]

Rgba & operator= ( Rgba && )

default

operator==()

bool operator==

(

const Rgba &

other

)

const

r()

double r

(

)

const

Red.

rgba()

Eigen::Vector4d rgba

(

)

const

Returns all four elements in order.

scale_rgb()

Rgba scale_rgb

(

double

scale

)

const

Computes a new Rgba color by multiplying the color channels (rgb) by the given scalar scalar.

All resultant channel values saturate at one. The result has this Rgba's alpha values.

Precondition

scale >= 0.

Serialize()

template<typename Archive>

void Serialize

(

Archive *

a

)

Passes this object to an Archive.

In YAML, an Rgba is represented by a mapping of the symbol rgba to an array-like list of three or four numbers. E.g.,

 rgba: [0.5, 0.5, 1.0]

or

 rgba: [0.5, 0.5, 1.0, 0.5]

such that the first three values are red, green, and blue, respectively. If no fourth value is provided, alpha is defined a 1.0.

When another struct has an Rgba-valued member (e.g., systems::sensors::CameraConfig::background), remember to include the full mapping. For example, imagine the struct:

struct Foo {
  Rgba color1;
  Rgba color2;
};

The correct yaml representation of this would be:

color1:
  rgba: [0.5, 0.5, 1.0]
color2:
  rgba: [1.0, 0.0, 0.0, 0.5]

The values of color1 and color2 are the mapping from rgba to the desired color tuples.

Refer to YAML Serialization for background.

set() [1/2]

void set

(

const Eigen::Ref< const Eigen::VectorXd > &

rgba

)

Sets an (r, g, b, a) from a vector.

Exceptions

std::exception	if the vector is not size 3 or 4.
std::exception	if any values are outside of the range [0, 1].

set() [2/2]

void set	(	double	r,
		double	g,
		double	b,
		double	a = 1.0 )

Sets (r, g, b, a) values.

Exceptions

std::exception

if any values are outside of the range [0, 1].

to_string()

std::string to_string

(

)

const

Converts the Rgba value to a string representation.

update()

void update	(	std::optional< double >	r = {},
		std::optional< double >	g = {},
		std::optional< double >	b = {},
		std::optional< double >	a = {} )

Updates individual (r, g, b, a) values; any values not provided will remain unchanged.

Exceptions

std::exception

if any values are outside of the range [0, 1].

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The documentation for this class was generated from the following file:

• drake/geometry/rgba.h