Version 5.0 The LEDA User Manual

Chapter 17
Graphics
This section describes the data types color, window, panel, and menu.
17.1 Colors ( color )
1. Definition
The data type color is the type of all colors available for drawing operations in windows
(cf. 17.2). 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
) black, white, red, green, blue, yellow, violet, orange;
cyan, brown, pink, green2, blue2, grey1, grey2, grey3.
#include < LEDA/graphics/color.h >
2. Creation
color col; creates a color with rgb-value (0, 0, 0) (i.e. black).
color
color
col(int r, int g, int b);
col(const char ∗ name);
creates a color with rgb-value (r, g, b).
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.
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