.\"***************************************************************************
-.\" Copyright (c) 1998-2000,2002 Free Software Foundation, Inc. *
+.\" Copyright (c) 1998-2016,2018 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. *
.\"***************************************************************************
.\"
-.\" Author: Thomas E. Dickey <dickey@clark.net> 1997,1999,2000
+.\" Author: Thomas E. Dickey 1997,1999,2000,2005
.\"
-.\" $Id: default_colors.3x,v 1.16 2002/02/16 22:39:52 tom Exp $
+.\" $Id: default_colors.3x,v 1.27 2018/07/28 22:08:59 tom Exp $
.TH default_colors 3X ""
.SH NAME
\fBuse_default_colors\fR,
\fBassume_default_colors\fR \- use terminal's default colors
.SH SYNOPSIS
\fB#include <curses.h>\fP
-
+.sp
\fBint use_default_colors(void);\fP
.br
\fBint assume_default_colors(int fg, int bg);\fP
.SH DESCRIPTION
-The
-.I use_default_colors()
-and
-.I assume_default_colors()
+The \fBuse_default_colors\fP and \fBassume_default_colors\fP
functions are extensions to the curses library.
They are used with terminals that support ISO 6429 color, or equivalent.
These terminals allow the application to reset color to an unspecified
For example, there are several implementations of the \fBls\fP program
which use colors to denote different file types or permissions.
These "color ls" programs do not necessarily modify the background color,
-typically using only the \fIsetaf\fP terminfo capability to set the
+typically using only the \fBsetaf\fP terminfo capability to set the
foreground color.
Full-screen applications that use default colors can achieve similar
visual effects.
.PP
-The first function,
-.I use_default_colors()
+The first function, \fBuse_default_colors\fP
tells the curses library to assign terminal default
-foreground/background colors to color number -1. So init_pair(x,COLOR_RED,-1)
-will initialize pair x as red on default background and init_pair(x,-1,COLOR_BLUE) will
+foreground/background colors to color number \-1.
+So init_pair(x,COLOR_RED,\-1)
+will initialize pair x as red on default background
+and init_pair(x,\-1,COLOR_BLUE) will
initialize pair x as default foreground on blue.
.PP
-The other,
-.I assume_default_colors()
+The other, \fBassume_default_colors\fP
is a refinement which tells which colors to paint for color pair 0.
-This function recognizes a special color number -1,
+This function recognizes a special color number \-1,
which denotes the default terminal color.
.PP
The following are equivalent:
.br
.I use_default_colors();
.br
-.I assume_default_colors(-1,-1);
+.I assume_default_colors(\-1,\-1);
.RE
.PP
These are ncurses extensions.
For other curses implementations, color
-number -1 does not mean anything, just as for ncurses before a
-successful call of \fIuse_default_colors()\fP or \fIassume_default_colors()\fP.
+number \-1 does not mean anything, just as for ncurses before a
+successful call of \fBuse_default_colors\fP or \fBassume_default_colors\fP.
.PP
Other curses implementations do not allow an application to modify color pair 0.
They assume that the background is COLOR_BLACK,
but do not ensure that the color pair 0 is painted to match the
assumption.
If your application does not use either
-.I use_default_colors()
+.B use_default_colors
or
-.I assume_default_colors()
+.B assume_default_colors
ncurses will paint a white foreground (text) with black background
for color pair 0.
.SH RETURN VALUE
-These functions return the integer \fBERR\fP upon failure and \fBOK\fP on success.
+These functions return the integer \fBERR\fP upon failure
+and \fBOK\fP on success.
They will fail if either the terminal does not support
-the \fIorig_pair\fP or \fIorig_colors\fP capability.
-If the \fIinitialize_pair\fP capability is found, this causes an
+the \fBorig_pair\fP or \fBorig_colors\fP capability.
+If the \fBinitialize_pair\fP capability is not found, this causes an
error as well.
.SH NOTES
-Associated with this extension, the \fBinit_pair\fR(3X) function accepts
-negative arguments to specify default foreground or background
-colors.
+Associated with this extension, the \fBinit_pair\fR function accepts
+negative arguments to specify default foreground or background colors.
+.PP
+The \fBuse_default_colors\fP function was added to support \fIded\fP.
+This is a full-screen application which uses curses to manage only part
+of the screen.
+The bottom portion of the screen, which is of adjustable
+size, is left uncolored to display the results from shell commands.
+The top portion of the screen colors filenames using a scheme like the
+"color ls" programs.
+Attempting to manage the background color of the screen for this application
+would give unsatisfactory results for a variety of reasons.
+This extension was devised after
+noting that color xterm (and similar programs) provides a background color
+which does not necessarily correspond to any of the ANSI colors.
+While a special terminfo entry could be constructed using nine colors,
+there was no mechanism provided within curses to account for the related
+\fBorig_pair\fP and \fBback_color_erase\fP capabilities.
+.PP
+The \fBassume_default_colors\fP function was added to solve
+a different problem: support for applications which would use
+environment variables and other configuration to bypass curses'
+notion of the terminal's default colors, setting specific values.
.SH PORTABILITY
-These routines are specific to ncurses. They were not supported on
-Version 7, BSD or System V implementations. It is recommended that
+These routines are specific to ncurses.
+They were not supported on
+Version 7, BSD or System V implementations.
+It is recommended that
any code depending on them be conditioned using NCURSES_VERSION.
.SH SEE ALSO
\fBcurs_color\fR(3X),
.SH AUTHOR
Thomas Dickey (from an analysis of the requirements for color xterm
for XFree86 3.1.2C, February 1996).
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