Страницы справочника OS X

Эта страница руководства является частью версии 5.0 Инструментов XCode

Читать страницы руководства

curs_color(3X)                                                                                curs_color(3X)



NAME
       start_color, init_pair, init_color, has_colors, can_change_color, color_content, pair_content,
       COLOR_PAIR - curses color manipulation routines

SYNOPSIS
       # 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);

DESCRIPTION
   Overview
       curses support color attributes on terminals with that capability.  To use these routines start_color
       must  be called, usually right after initscr.  Colors are always used in pairs (referred to as color-pairs). colorpairs).
       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 init_pair.  After it has been initialized, COLOR_PAIR(n), a macro defined in <curses.h>,  can
       be used as a new video attribute.

       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 terminal has color capabilities and whether the programmer can change the
       colors.  The routine color_content allows a programmer to extract 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 col-ors, colors,
       ors,  and  before  any  other color manipulation 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.   For
       portable applications:

       -    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.  Color pair 0 is as-sumed assumed
            sumed to be white on black, but is actually whatever the terminal  implements  before  color  is
            initialized.  It cannot be modified by the application.

       If  the  color-pair  was  previously initialized, the screen is refreshed and all occurrences of that
       color-pair are changed to the new definition.

       As an extension, ncurses allows you to set color pair 0 via the assume_default_colors routine, or  to
       specify  the  use of default colors (color number -1) if you first invoke the use_default_colors rou-tine. routine.
       tine.

       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 compo-nents). components).
       nents).  The value of the first argument must be between 0 and COLORS.  (See the section  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 defini-tion. definition.
       tion.

       The has_colors routine requires no arguments.  It returns TRUE if the terminal can manipulate colors;
       otherwise, it 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; other, it returns FALSE.  This routine facilitates  writing  termi-nal-independent terminal-independent
       nal-independent programs.

       The  color_content  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
       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 programmers 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 fore-ground foreground
       ground and the background color numbers.  The value of the first argument must be between 1 and  COL-OR_PAIRS-1. COLOR_PAIRS-1.
       OR_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 VALUE
       The routines can_change_color() and has_colors() return TRUE or FALSE.

       All  other  routines  return  the integer ERR upon failure and an OK (SVr4 specifies only "an integer
       value other than ERR") upon successful completion.

       X/Open defines no error conditions.  This implementation will return ERR on  attempts  to  use  color
       values  outside the range 0 to COLORS-1 (except for the default colors extension), or use color pairs
       outside the range 0 to COLOR_PAIR-1.  Color values used in init_color must be in the range 0 to 1000.
       An  error  is  returned from all functions if the terminal has not been initialized.  An error is re-turned returned
       turned from secondary functions such as init_pair if start_color was not called.

              init_color
                   returns an error if the terminal does not support this feature,  e.g.,  if  the  initial-ize_color initialize_color
                   ize_color capability is absent from the terminal description.

              start_color
                   returns an error If the color table cannot be allocated.

NOTES
       In  the ncurses implementation, there is a separate color activation flag, color palette, color pairs
       table, and associated COLORS and COLOR_PAIRS counts for each screen; the  start_color  function  only
       affects  the  current  screen.   The SVr4/XSI interface is not really designed with this in mind, and
       historical implementations may use a single shared color palette.

       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 operations, see curs_bkgd(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  A_BOLD  at-tribute. attribute.
            tribute.

       -    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.

PORTABILITY
       This implementation satisfies XSI Curses's minimum maximums for COLORS and COLOR_PAIRS.

       The init_pair routine accepts negative values of foreground  and  background  color  to  support  the
       use_default_colors extension, but only if that routine has been first invoked.

       The assumption that COLOR_BLACK is the default background color for all terminals can be modified us-ing using
       ing the assume_default_colors extension.

       This implementation checks the pointers, e.g., for the values returned by color_content and pair_con-tent, pair_content,
       tent, and will treat those as optional parameters when null.

SEE ALSO
       curses(3X), curs_initscr(3X), curs_attr(3X), default_colors(3X)



                                                                                              curs_color(3X)