curs_color, start_color, init_pair, init_color, has_colors,
can_change_color, color_content, pair_content,
COLOR_PAIR, COLOR_PAIRS, COLORS, PAIR_NUMBER - Curses
color-manipulation routines and variables
# include <curses.h>
int start_color(
void ); int init_pair(
short pair,
short f,
short b ); int init_color(
short color,
short r,
short g,
short b ); bool has_colors(
void ); bool can_change_color(
void ); int color_content(
short color,
short *r,
short *g,
short *b ); int pair_content(
short pair,
short *f,
short *b ); int COLOR_PAIR(
int n ); int PAIR_NUMBER(
int value );
Curses Library (libcurses)
Interfaces documented on this reference page conform to
industry standards as follows:
start_color, init_pair, init_color, has_colors,
can_change_color, color_content, pair_content, COLOR_PAIR,
PAIR_NUMBER: XCURSES4.2
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
The Curses library includes routines that manipulate
color-on-color alphanumeric terminals. To use these routines,
applications must call start_color, usually right
after initscr. 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). An application
calls init_pair to initialize a color-pair. After the
color-pair is initialized, applications can call
COLOR_PAIR(n) to use color attributes.
If a terminal is capable of redefining colors, applications
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 terminal has color capabilities and whether
the application can change the colors. The routine
color_content allows an application to identify the
amounts of red, green, and blue components in an initialized
color. The routine pair_content allows the application
to find out how a given color-pair is currently
defined.
Routine Descriptions [Toc] [Back]
The start_color routine requires no arguments. It must be
called if the application uses colors, and before the
application calls any other color manipulation routine. It
is good practice to call this routine right after initscr.
The start_color routine initializes eight basic colors
(black, red, green, yellow, blue, magenta, cyan, and
white) and two global variables (COLORS and COLOR_PAIRS,
which respectively define the maximum number of colors and
color-pairs the terminal can support). The start_color
routine also restores the colors on the terminal to the
values they had when the terminal was turned on.
The init_pair routine changes the definition of a colorpair.
This routine takes three arguments that are identification
numbers for the following: The color-pair to be
changed The foreground color The background color
The value of the first argument must be between 1 and the
smaller of either 63 or COLOR_PAIRS-1. The values 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 are
changed to the new definition.
The init_color routine changes the definition of a color.
This routine 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, respectively).
The value of the first argument must be between 0 and COLORS.
(See the subsection Colors for the default color
index.) Each of the last three arguments 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, the
routine returns FALSE. This routine 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; otherwise, the routine 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. This routine requires four arguments: the color
number, and three addresses (of short data type) 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 which
colors a given color-pair consists of. This routine
requires three arguments: the color-pair number, and two
addresses (of short data type) for storing the numbers for
the foreground and background colors. The value of the
first argument must be between 1 and the smaller of 63 or
COLOR_PAIRS-1. The values that are stored at the addresses
pointed to by the second and third arguments are between 0
and COLORS.
The COLOR_PAIR(n) macro returns the value of the colorpair
whose number is n. This value is the color attribute
as it would be extracted from a chtype variable. Conversely,
the macro PAIR_NUMBER(value) returns the number
of the color-pair associated with the color attribute
value.
Colors [Toc] [Back]
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
The header file <curses.h> automatically includes the
header file <stdio.h>.
Note that COLOR_PAIR and PAIR_NUMBER may be macros.
The COLOR_PAIR, PAIR_NUMBER, can_change_color, and
has_colors routines return values as indicated in the
DESCRIPTION section.
All other routines return ERR upon failure and OK upon
successful completion.
Functions: curses(3), curs_attr_get(3), curs_initscr(3)
Others: standards(5)
curs_color(3)
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