CGAL::IO::Color Class Reference

#include <CGAL/IO/Color.h>

Definition

An object of the class Color is a color available for drawing operations in many CGAL output streams.

Each color is defined by a 4 unsigned chars (r,g,b,a) with 0 \(\le\) r,g,b,a \( \le \) 255, the so-called rgba-value of the color.

The alpha parameter (representing transparency) is often ignored and left to its default value (255 = no transparency), which is why we often refer to the rgb-value of the color.

Related Functions
(Note that these are not member functions.)
Color	black ()
	Constructs Color(0,0,0).
Color	blue ()
	Constructs Color(0,0,255).
Color	deep_blue ()
	Constructs Color(10,0,100).
Color	gray ()
	Constructs Color(100,100,100).
Color	green ()
	Constructs Color(0,255,0).
Color	orange ()
	Constructs Color(235,150,0).
Color	purple ()
	Constructs Color(100,0,70).
Color	red ()
	Constructs Color(255,0,0).
Color	violet ()
	Constructs Color(255,0,255).
Color	white ()
	Constructs Color(255,255,255).
Color	yellow ()
	Constructs Color(255,255,0).

Creation
	Color ()
	creates a color with rgba-value (0,0,0,255), i.e. black.
	Color (unsigned char red, unsigned char green, unsigned char blue, unsigned char alpha=255)
	creates a color with rgba-value (red,green,blue,alpha).

Component Access
unsigned char	red () const
	returns the red component.
unsigned char &	red ()
	returns a reference on the red component.
unsigned char	green () const
	returns the green component.
unsigned char &	green ()
	returns a reference on the green component.
unsigned char	blue () const
	returns the blue component.
unsigned char &	blue ()
	returns a reference on the blue component.
unsigned char	alpha () const
	returns the alpha component.
unsigned char &	alpha ()
	returns a reference on the alpha component.

Array Access
unsigned char	operator[] (std::size_t i) const
	returns the \(i^{th}\) component of the rgb color (the \(0^{th}\) is red, the \(1^{st}\) is green, the \(2^{nd}\) is blue and the \(3^{rd}\) is alpha).
unsigned char &	operator[] (std::size_t i)
	returns a reference on the \(i^{th}\) component of the rgb color (the \(0^{th}\) is red, the \(1^{st}\) is green, the \(2^{nd}\) is blue and the \(3^{rd}\) is alpha).
const std::array< unsigned char, 4 > &	to_rgba () const
	returns the array with rgba values.
const std::array< unsigned char, 3 > &	to_rgb () const
	returns the array with rgb values.
std::array< double, 3 >	to_hsv () const
	computes the hsv (hue, saturation, value) values and returns an array representing them as float values between 0 and 1.

Modification
Color &	set_rgb (unsigned char red, unsigned char green, unsigned char blue, unsigned char alpha=255)
	replaces the rgb values of the colors by the one given as parameters.
Color &	set_hsv (double hue, double saturation, double value, unsigned char alpha=255)
	replaces the rgb values of the colors by the conversion to rgb of the hsv values given as parameters.