.\"***************************************************************************
-.\" Copyright (c) 1998-2015,2016 Free Software Foundation, Inc. *
+.\" Copyright (c) 1998-2016,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" copy of this software and associated documentation files (the *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_color.3x,v 1.43 2016/07/30 15:22:11 tom Exp $
+.\" $Id: curs_color.3x,v 1.50 2017/04/01 19:57:19 tom Exp $
.TH curs_color 3X ""
.ie \n(.g .ds `` \(lq
.el .ds `` ``
.hy 0
.SH NAME
\fBstart_color\fR,
-\fBinit_pair\fR,
-\fBinit_color\fR,
-.\" .br
\fBhas_colors\fR,
\fBcan_change_color\fR,
-.\" .br
+\fBinit_pair\fR,
+\fBinit_color\fR,
\fBcolor_content\fR,
\fBpair_content\fR,
-.\" .br
\fBCOLOR_PAIR\fR,
\fBPAIR_NUMBER\fR \- \fBcurses\fR color manipulation routines
.ad
\fB#include <curses.h>\fR
.sp
\fBint start_color(void);\fR
+.sp
+\fBbool has_colors(void);\fR
.br
+\fBbool can_change_color(void);\fR
+.sp
\fBint init_pair(short pair, short f, short b);\fR
.br
\fBint init_color(short color, short r, short g, short b);\fR
-.sp
-\fBbool has_colors(void);\fR
.br
-\fBbool can_change_color(void);\fR
+/* extensions */
+.br
+\fBint init_extended_pair(int pair, int f, int b);\fR
+.br
+\fBint init_extended_color(int color, int r, int g, int b);\fR
.sp
\fBint color_content(short color, short *r, short *g, short *b);\fR
.br
\fBint pair_content(short pair, short *f, short *b);\fR
+.br
+/* extensions */
+.br
+\fBint extended_color_content(int color, int *r, int *g, int *b);\fR
+.br
+\fBint extended_pair_content(int pair, int *f, int *b);\fR
.sp
\fBint COLOR_PAIR(int n);\fR
.br
Those do not combine its parameter with a color pair.
Consequently those calls use only the window attribute or
the background character.
-.SS Routine Descriptions
+.SH CONSTANTS
+.PP
+In \fB<curses.h>\fR the following macros are defined.
+These are the standard colors (ISO-6429).
+\fBcurses\fR also assumes that \fBCOLOR_BLACK\fR is the default
+background color for all terminals.
+.PP
+.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
+.PP
+Some terminals support more than the eight (8) \*(lqANSI\*(rq colors.
+There are no standard names for those additional colors.
+.SH VARIABLES
+.SS COLORS
+is initialized by \fBstart_color\fP to the maximum number of colors
+the terminal can support.
+.SS COLOR_PAIRS
+is initialized by \fBstart_color\fP to the maximum number of color pairs
+the terminal can support.
+.SH FUNCTIONS
+.SS start_color
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.
These limits apply to color values and color pairs.
Values outside these limits are not legal, and may result in a runtime error:
.bP
-\fBCOLORS\fP corresponds to the terminal database's \fBmax_colors\fP capability,
-which is typically a signed 16-bit integer (see \fBterminfo\fR(\*n)).
+\fBCOLORS\fP corresponds to the terminal database's \fBmax_colors\fR capability,
+(see \fBterminfo\fR(\*n)).
.bP
color values are expected to be in the range \fB0\fP to \fBCOLORS\-1\fP,
inclusive (including \fB0\fP and \fBCOLORS\-1\fP).
to denote the \fIdefault color\fP (see \fBuse_default_colors\fP).
.bP
\fBCOLOR_PAIRS\fP corresponds to the terminal database's \fBmax_pairs\fP capability,
-which is typically a signed 16-bit integer (see \fBterminfo\fR(\*n)).
+(see \fBterminfo\fR(\*n)).
.bP
legal color pair values are in the range \fB1\fP to \fBCOLOR_PAIRS\-1\fP,
inclusive.
Color pair \fB0\fP is assumed to be white on black,
but is actually whatever the terminal implements before color is initialized.
It cannot be modified by the application.
+.SS has_colors
+.PP
+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.
+.SS can_change_color
+.PP
+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.
+.SS init_pair
.PP
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
are changed to the new definition.
.PP
As an extension, ncurses allows you to set color pair \fB0\fP via
-the \fBassume_default_colors\fR routine, or to specify the use of
+the \fBassume_default_colors\fR(3X) routine, or to specify the use of
default colors (color number \fB\-1\fR) if you first invoke the
-\fBuse_default_colors\fR routine.
+\fBuse_default_colors\fR(3X) routine.
+.SS init_color
.PP
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).
+.bP
The first argument must be a legal color value;
default colors are not allowed here.
(See the section \fBColors\fR for the default color index.)
+.bP
Each of the last three arguments
must be a value in the range \fB0\fP through \fB1000\fP.
+.PP
When \fBinit_color\fR is used, all
occurrences of that color on the screen immediately change to the new
definition.
-.PP
-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.
-.PP
-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.
+.SS color_content
.PP
The \fBcolor_content\fR routine gives programmers a way to find the intensity
of the red, green, and blue (RGB) components in a color.
of \fBshort\fRs for storing
the information about the amounts of red, green, and blue components in the
given color.
+.bP
The first argument must be a legal color value, i.e.,
\fB0\fP through \fBCOLORS\-1\fP, inclusive.
+.bP
The values that are stored at the addresses pointed to by the
last three arguments are in the range
\fB0\fP (no component) through \fB1000\fP (maximum amount of component), inclusive.
+.SS pair_content
.PP
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.
+.bP
The first argument must be a legal color value,
i.e., in the range \fB1\fP through \fBCOLOR_PAIRS\-1\fR, inclusive.
+.bP
The values that are stored at the addresses pointed
to by the second and third arguments are in the
range \fB0\fP through \fBCOLORS\fR, inclusive.
+.SS PAIR_NUMBER
.PP
\fBPAIR_NUMBER(\fR\fIattrs\fR) extracts the color
value from its \fIattrs\fP parameter and returns it as a color pair number.
+.SS COLOR_PAIR
Its inverse \fBCOLOR_PAIR(\fR\fIn\fR\fB)\fR converts a color pair number
to an attribute.
Attributes can hold color pairs in the range 0 to 255.
If you need a color pair larger than that, you must use functions
such as \fBattr_set\fP (which pass the color pair as a separate parameter)
rather than the legacy functions such as \fBattrset\fP.
-.SS Colors
-In \fB<curses.h>\fR the following macros are defined.
-These are the standard colors (ISO-6429).
-\fBcurses\fR also assumes that \fBCOLOR_BLACK\fR is the default
-background color for all terminals.
-.PP
-.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
+The routines \fBcan_change_color\fR and \fBhas_colors\fR return \fBTRUE\fR
or \fBFALSE\fR.
.PP
All other routines return the integer \fBERR\fR upon failure and an \fBOK\fR
.PP
X/Open defines no error conditions.
This implementation will return \fBERR\fR on attempts to
-use color values outside the range \fB0\fP to COLORS\-1
+use color values outside the range \fB0\fP to \fBCOLORS\fP\-1
(except for the default colors extension),
or use color pairs outside the range \fB0\fP to \fBCOLOR_PAIRS\-1\fP.
Color values used in \fBinit_color\fP must be in the range \fB0\fP to \fB1000\fP.
.TP 5
\fBinit_color\fP
returns an error if the terminal does not support
-this feature, e.g., if the \fIinitialize_color\fP capability is absent
+this feature, e.g., if the \fBinitialize_color\fP capability is absent
from the terminal description.
.TP 5
\fBstart_color\fP
returns an error if the color table cannot be allocated.
.RE
.SH NOTES
-In the \fIncurses\fR implementation, there is a separate color activation flag,
-color palette, color pairs table, and associated COLORS and COLOR_PAIRS counts
+In the \fBncurses\fR implementation, there is a separate color activation flag,
+color palette, color pairs table, and associated \fBCOLORS\fP and \fBCOLOR_PAIRS\fP counts
for each screen; the \fBstart_color\fR 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.
.PP
-Note that setting an implicit background color via a color pair affects only
+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 \fBcurs_bkgd\fR(3X).
.PP
-Several caveats apply on 386 and 486 machines with VGA-compatible graphics:
+Several caveats apply on older x86 machines (e.g., i386, i486) with VGA-compatible graphics:
.bP
COLOR_YELLOW is actually brown.
To get yellow, use COLOR_YELLOW combined with the \fBA_BOLD\fR attribute.
for \fBCOLORS\fR and \fBCOLOR_PAIRS\fR.
.PP
The \fBinit_pair\fP routine accepts negative values of foreground
-and background color to support the \fBuse_default_colors\fP extension,
+and background color to support the \fBuse_default_colors\fR(3X) extension,
but only if that routine has been first invoked.
.PP
The assumption that \fBCOLOR_BLACK\fR is the default
background color for all terminals can be modified using the
-\fBassume_default_colors\fP extension.
+\fBassume_default_colors\fR(3X) extension.
.PP
This implementation checks the pointers,
e.g., for the values returned by
\fBcolor_content\fP and \fBpair_content\fP,
and will treat those as optional parameters when null.
+.PP
+X/Open Curses does not specify a limit for the number of colors and
+color pairs which a terminal can support.
+However, in its use of \fBshort\fP for the parameters,
+it carries over SVr4's implementation detail for the compiled
+terminfo database, which uses signed 16-bit numbers.
+This implementation provides extended versions of those functions
+which use \fBshort\fP parameters,
+allowing applications to use larger color- and pair-numbers.
.SH SEE ALSO
\fBcurses\fR(3X),
\fBcurs_initscr\fR(3X),
projects / ncurses.git / blobdiff