curs_color(3CURSES) Curses Library Functions curs_color(3CURSES)NAME
curs_color, start_color, init_pair, init_color, has_colors,
can_change_color, color_content, pair_content - curses color manipula‐
tion functions
SYNOPSIS
cc [ flag ... ] file ... -lcurses [ library ... ]
#include <curses.h>
int start_color(void);
int init_pair(short pair, short fg, short bg);
int init_color(short color, short red, short green, short blue);
bool has_colors(void);
bool can_change_color(void);
int color_content(short color, short *redp, short *greenp, short *bluep);
int pair_content(short pair, short *fgp, short *bgp);
DESCRIPTION
Overview
curses provides routines that manipulate color on color alphanumeric
terminals. To use these routines start_color() must be called, usually
right after initscr(). See curs_initscr(3CURSES). Colors are always
used in pairs (referred to as color-pairs). A color-pair consists of a
foreground color (for characters) and a background color (for the field
on which the characters are displayed). A programmer initializes a
color-pair with the routine init_pair. After it has been initialized,
COLOR_PAIR(n), a macro defined in <curses.h>, can be used in the same
ways other video attributes can be used. If a terminal is capable of
redefining colors, the programmer can use the routine init_color() to
change the definition of a color. The routines has_colors() and
can_change_color() return TRUE or FALSE, depending on whether the ter‐
minal has color capabilities and whether the programmer can change the
colors. The routine color_content() allows a programmer to identify the
amounts of red, green, and blue components in an initialized color. The
routine pair_content() allows a programmer to find out how a given
color-pair is currently defined.
Routine Descriptions
The start_color() routine requires no arguments. It must be called if
the programmer wants to use colors, and before any other color manipu‐
lation routine is called. It is good practice to call this routine
right after initscr(). start_color() initializes eight basic colors
(black, red, green, yellow, blue, magenta, cyan, and white), and two
global variables, COLORS and COLOR_PAIRS (respectively defining the
maximum number of colors and color-pairs the terminal can support). It
also restores the colors on the terminal to the values they had when
the terminal was just turned on.
The init_pair() routine changes the definition of a color-pair. It
takes three arguments: the number of the color-pair to be changed, the
foreground color number, and the background color number. The value of
the first argument must be between 1 and COLOR_PAIRS−1. The value of
the second and third arguments must be between 0 and COLORS. If the
color-pair was previously initialized, the screen is refreshed and all
occurrences of that color-pair is changed to the new definition.
The init_color() routine changes the definition of a color. It takes
four arguments: the number of the color to be changed followed by three
RGB values (for the amounts of red, green, and blue components). The
value of the first argument must be between 0 and COLORS. (See the sec‐
tion Colors for the default color index.) Each of the last three argu‐
ments must be a value between 0 and 1000. When init_color() is used,
all occurrences of that color on the screen immediately change to the
new definition.
The has_colors() routine requires no arguments. It returns TRUE if the
terminal can manipulate colors; otherwise, it returns FALSE. This rou‐
tine facilitates writing terminal-independent programs. For example, a
programmer can use it to decide whether to use color or some other
video attribute.
The can_change_color() routine requires no arguments. It returns TRUE
if the terminal supports colors and can change their definitions;
other, it returns FALSE. This routine facilitates writing terminal-
independent programs.
The color_content() routine gives users a way to find the intensity of
the red, green, and blue (RGB) components in a color. It requires four
arguments: the color number, and three addresses of shorts for storing
the information about the amounts of red, green, and blue components in
the given color. The value of the first argument must be between 0 and
COLORS. The values that are stored at the addresses pointed to by the
last three arguments are between 0 (no component) and 1000 (maximum
amount of component).
The pair_content() routine allows users to find out what colors a given
color-pair consists of. It requires three arguments: the color-pair
number, and two addresses of shorts for storing the foreground and the
background color numbers. The value of the first argument must be
between 1 and COLOR_PAIRS−1. The values that are stored at the
addresses pointed to by the second and third arguments are between 0
and COLORS.
Colors
In <curses.h> the following macros are defined. These are the default
colors. curses also assumes that COLOR_BLACK is the default background
color for all terminals.
COLOR_BLACK
COLOR_RED
COLOR_GREEN
COLOR_YELLOW
COLOR_BLUE
COLOR_MAGENTA
COLOR_CYAN
COLOR_WHITE
RETURN VALUES
All routines that return an integer return ERR upon failure and OK upon
successful completion.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Unsafe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOcurs_attr(3CURSES), curs_initscr(3CURSES), curses(3CURSES),
attributes(5)NOTES
The header <curses.h> automatically includes the headers <stdio.h> and
<unctrl.h>.
SunOS 5.10 31 Dec 1996 curs_color(3CURSES)
