next up previous contents index
Next: Windows ( window ) Up: Graphics Previous: Graphics   Contents   Index


Colors ( color )

Definition

The data type color is the type of all colors available for drawing operations in windows (cf. Windows). Each color is defined by a triple of integers (r, g, b) with 0 < = r, g, b < = 255 , the so-called rgb-value of the color. The number of available colors is restricted and depends on the underlying hardware. Colors can be created from rgb-values, from names in a color data base (X11), or from the 16 integer constants (enumeration in < LEDA/graphics/x_window.htex2html_wrap_inline> ) black , white , red , green , blue , yellow , violet , orange ; cyan , brown , pink , green2 , blue2 , grey1 , grey2 , grey3 .

#include < LEDA/graphics/color.h >

Creation

color col creates a color with rgb-value (0, 0, 0) (i.e. black).

color col(int r, int g, int b) creates a color with rgb-value (r, g, b) .

color col(const char* name) creates a color and initializes it with the rgb-value of color name from the X11 color data base ((0, 0, 0) if name does not exist).

color col(int i) creates a color and initializes it with one of the 16 predefined colors. Here i is one of the 16 integer constants black , white , red , green , blue , yellow , violet , orange , cyan , brown , pink , green2 , blue2 , grey1 , grey2 , or grey3 .

Operations

void col.set_rgb(int r, int g, int b)
    sets the rgb-value of col to (r, g, b) .

void col.get_rgb(int& r, int& g, int& b)
    assigns the rgb-value of col to (r, g, b) .

void col.set_red(int r) changes the r-value of col to r .

void col.set_green(int g) changes the g-value of col to g .

void col.set_blue(int b) changes the b-value of col to b .


next up previous contents index
Next: Windows ( window ) Up: Graphics Previous: Graphics   Contents   Index
Christian Uhrig 2017-04-07