.TH curs_color 3X "" .SH NAME \fBstart_color\fR, \fBinit_pair\fR, \fBinit_color\fR, \fBhas_colors\fR, \fBcan_change_color\fR, \fBcolor_content\fR, \fBpair_content\fR - \fBcurses\fR color manipulation routines .SH SYNOPSIS \fB# include \fR .br \fBint start_color(void);\fR .br \fBint init_pair(short pair, short f, short b);\fR .br \fBint init_color(short color, short r, short g, short b);\fR .br \fBbool has_colors(void);\fR .br \fBbool can_change_color(void);\fR .br \fBint color_content(short color, short *r, short *g, short *b);\fR .br \fBint pair_content(short pair, short *f, short *b);\fR .br .SH DESCRIPTION .SS Overview \fBcurses\fR support color attributes on terminals with that capability. To use these routines \fBstart_color\fR must be called, usually right after \fBinitscr\fR. 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 blank field on which the characters are displayed). A programmer initializes a color-pair with the routine \fBinit_pair\fR. After it has been initialized, \fBCOLOR_PAIR\fR(\fIn\fR), a macro defined in \fB\fR, can be used as a new video attribute. If a terminal is capable of redefining colors, the programmer can use the routine \fBinit_color\fR to change the definition of a color. The routines \fBhas_colors\fR and \fBcan_change_color\fR return \fBTRUE\fR or \fBFALSE\fR, depending on whether the terminal has color capabilities and whether the programmer can change the colors. The routine \fBcolor_content\fR allows a programmer to extract the amounts of red, green, and blue components in an initialized color. The routine \fBpair_content\fR allows a programmer to find out how a given color-pair is currently defined. .SS Routine Descriptions The \fBstart_color\fR routine requires no arguments. It must be called if the programmer wants to use colors, and before any other color manipulation routine is called. It is good practice to call this routine right after \fBinitscr\fR. \fBstart_color\fR initializes eight basic colors (black, red, green, yellow, blue, magenta, cyan, and white), and two global variables, \fBCOLORS\fR and \fBCOLOR_PAIRS\fR (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 \fBinit_pair\fR 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 \fB1\fR and \fBCOLOR_PAIRS-1\fR. The value of the second and third arguments must be between 0 and \fBCOLORS\fR (the 0 color pair is wired to white on black and cannot be changed). 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 \fBinit_color\fR 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 \fB0\fR and \fBCOLORS\fR. (See the section \fBColors\fR for the default color index.) Each of the last three arguments must be a value between 0 and 1000. When \fBinit_color\fR is used, all occurrences of that color on the screen immediately change to the new definition. The \fBhas_colors\fR routine requires no arguments. It returns \fBTRUE\fR if the terminal can manipulate colors; otherwise, it returns \fBFALSE\fR. 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 \fBcan_change_color\fR routine requires no arguments. It returns \fBTRUE\fR if the terminal supports colors and can change their definitions; other, it returns \fBFALSE\fR. This routine facilitates writing terminal-independent programs. The \fBcolor_content\fR routine gives programmers 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 \fBshort\fRs 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 \fBCOLORS\fR. 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 \fBpair_content\fR routine allows programmers to find out what colors a given color-pair consists of. It requires three arguments: the color-pair number, and two addresses of \fBshort\fRs for storing the foreground and the background color numbers. The value of the first argument must be between 1 and \fBCOLOR_PAIRS-1\fR. The values that are stored at the addresses pointed to by the second and third arguments are between 0 and \fBCOLORS\fR. .SS Colors In \fB\fR the following macros are defined. These are the default colors. \fBcurses\fR also assumes that \fBCOLOR_BLACK\fR is the default background color for all terminals. .nf \fBCOLOR_BLACK\fR \fBCOLOR_RED\fR \fBCOLOR_GREEN\fR \fBCOLOR_YELLOW\fR \fBCOLOR_BLUE\fR \fBCOLOR_MAGENTA\fR \fBCOLOR_CYAN\fR \fBCOLOR_WHITE\fR .fi .SH RETURN VALUE The routines \fBcan_change_color()\fR and \fBhas_colors()\fR return \fBTRUE\fR or \fBFALSE\fR. All other routines return the integer \fBERR\fR upon failure and an \fBOK\fR (SVr4 specifies only "an integer value other than \fBERR\fR") upon successful completion. .SH NOTES Note that setting an implicit background color via a color pair affects only character cells that a character write operation explicitly touches. To change the background color used when parts of a window are blanked by erasing or scrolling operastions, see \fBcurs_bkgd\fR(3x). Several caveats apply on 386 and 486 machines with VGA-compatible graphics: COLOR_YELLOW is actually brown. To get yellow, use COLOR_YELLOW combined with the \fBA_BOLD\fR attribute. The A_BLINK attribute should in theory cause the background to go bright. This often fails to work, and even some cards for which it mostly works (such as the Paradise and compatibles) do the wrong thing when you try to set a bright "yellow" background (you get a blinking yellow foreground instead). Color RGB values are not settable. .SH PORTABILITY This implementation satisfies XSI Curses's minumum maximums for \fBCOLORS\fR and \fBCOLOR_PAIRS\fR. .SH SEE ALSO \fBcurses\fR(3X), \fBcurs_initscr\fR(3X), \fBcurs_attr\fR(3X) .\"# .\"# The following sets edit modes for GNU EMACS .\"# Local Variables: .\"# mode:nroff .\"# fill-column:79 .\"# End: