curses_color(3) - NetBSD Manual Pages

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CURSES_COLOR(3)         NetBSD 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 ALSO

     curses_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.

NetBSD 9.0                       July 20, 2009                      NetBSD 9.0