CURSES_COLOR(3) BSD Library Functions Manual CURSES_COLOR(3)NAME
curses_color, has_colors, can_change_color, start_color, init_pair,
pair_content, COLOR_PAIR, PAIR_NUMBER, init_color, color_content,
no_color_attributes — curses color manipulation routines
LIBRARY
Curses Library (libcurses, -lcurses)
SYNOPSIS
#include <curses.h>
bool
has_colors(void);
bool
can_change_color(void);
int
start_color(void);
int
init_pair(short pair, short fore, short back);
int
pair_content(short pair, short *fore, short *back);
int
COLOR_PAIR(int n);
int
PAIR_NUMBER(int val);
int
init_color(short color, short red, short green, short blue);
int
color_content(short color, short *red, short *green, short *blue);
attr_t
no_color_attributes(void);
extern int COLOR_PAIRS;
extern int COLORS;
DESCRIPTION
These functions manipulate color on terminals that support color
attributes.
The function has_colors() indicates whether a terminal is capable of dis‐
playing color attributes. It returns TRUE if the terminal is capable of
displaying color attributes and FALSE otherwise.
The function can_change_color() indicates whether a terminal is capable
of redefining colors. It returns TRUE if colors can be redefined and
FALSE if they can not.
The function start_color() initializes the curses color support on a ter‐
minal. It must be called before any color manipulation functions are
called on that terminal. The function initializes the eight basic colors
(black, red, green, yellow, blue, magenta, cyan and white) that are spec‐
ified using the color macros (such as COLOR_BLACK) defined in <curses.h>.
start_color() also initializes the global external variables COLORS and
COLOR_PAIRS. COLORS defines the number of colors that the terminal sup‐
ports and COLOR_PAIRS defines the number of color-pairs that the terminal
supports. These color-pairs are initialized to white foreground on black
background. start_color() sets the colors on the terminal to the curses
defaults of white foreground on black background unless the functions
assume_default_colors() or use_default_colors() have been called previ‐
ously.
The function init_pair(pair, fore, back) sets foreground color fore and
background color back for color-pair number pair. The valid range for
the color-pair pair is from 1 to COLOR_PAIRS - 1 and the valid range for
the colors is any number less than COLORS. Specifying a negative number
will set that color to the default foreground or background color. The 8
initial colors are defined as:
COLOR_BLACK
COLOR_RED
COLOR_GREEN
COLOR_YELLOW
COLOR_BLUE
COLOR_MAGENTA
COLOR_CYAN
COLOR_WHITE
Color-pair 0 is used as the default color pair, so changing this will
have no effect. Use the function assume_default_colors() to change the
default colors.
The function pair_content(pair, *fore, *back) stores the foreground and
background color numbers of color-pair pair in the variables fore and
back, respectively.
The macro COLOR_PAIR(n) gives the attribute value of color-pair number n.
This is the value that is used to set the attribute of a character to
this color-pair. For example,
attrset(COLOR_PAIR(2))
will display characters using color-pair 2.
The macro PAIR_NUMBER(val) gives the color-pair number associated with
the attribute value val.
The function init_color(color, red, green, blue) sets the red, green and
blue intensity components of color color to the values red, green and
blue, respectively. The minimum intensity value is 0 and the maximum
intensity value is 1000.
The function color_content(color, *red, *green, *blue) stores the red,
green and blue intensity components of color color in the variables red,
green, and blue, respectively.
The function no_color_attributes() returns those attributes that a termi‐
nal is unable to combine with color.
RETURN VALUES
The functions start_color(), init_pair(), pair_content(), init_color()
and color_content() return OK on success and ERR on failure.
SEE ALSOcurses_attributes(3), curses_background(3), curses_default_colors(3)STANDARDS
The NetBSD Curses library complies with the X/Open Curses specification,
part of the Single Unix Specification.
The function no_color_attributes() and the use of negative color numbers
are extensions to the X/Open Curses specification.
HISTORY
These functions first appeared in NetBSD 1.5.
BSD July 20, 2009 BSD
