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diff --git a/upstream/mageia-cauldron/man3/new_pair.3x b/upstream/mageia-cauldron/man3/new_pair.3x new file mode 100644 index 00000000..6aa948f7 --- /dev/null +++ b/upstream/mageia-cauldron/man3/new_pair.3x @@ -0,0 +1,166 @@ +.\"*************************************************************************** +.\" Copyright 2018-2022,2023 Thomas E. Dickey * +.\" Copyright 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 * +.\" "Software"), to deal in the Software without restriction, including * +.\" without limitation the rights to use, copy, modify, merge, publish, * +.\" distribute, distribute with modifications, sublicense, and/or sell * +.\" copies of the Software, and to permit persons to whom the Software is * +.\" furnished to do so, subject to the following conditions: * +.\" * +.\" The above copyright notice and this permission notice shall be included * +.\" in all copies or substantial portions of the Software. * +.\" * +.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * +.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * +.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * +.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * +.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * +.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * +.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE. * +.\" * +.\" Except as contained in this notice, the name(s) of the above copyright * +.\" holders shall not be used in advertising or otherwise to promote the * +.\" sale, use or other dealings in this Software without prior written * +.\" authorization. * +.\"*************************************************************************** +.\" +.\" Author: Thomas E. Dickey +.\" +.\" $Id: new_pair.3x,v 1.44 2023/12/16 20:32:22 tom Exp $ +.TH new_pair 3X 2023-12-16 "ncurses 6.4" "Library calls" +.ie \n(.g \{\ +.ds `` \(lq +.ds '' \(rq +.\} +.el \{\ +.ie t .ds `` `` +.el .ds `` "" +.ie t .ds '' '' +.el .ds '' "" +.\} +. +.de bP +.ie n .IP \(bu 4 +.el .IP \(bu 2 +.. +.SH NAME +\fB\%alloc_pair\fP, +\fB\%find_pair\fP, +\fB\%free_pair\fP \- +dynamically allocate \fIcurses\fR color pairs +.SH SYNOPSIS +.nf +\fB#include <curses.h> +.PP +\fBint alloc_pair(int \fIfg\fP, int \fIbg\fP); +\fBint find_pair(int \fIfg\fP, int \fIbg\fP); +\fBint free_pair(int \fIpair\fP); +.fi +.SH DESCRIPTION +These functions are an extension to the \fIcurses\fP library. +They permit an application to dynamically allocate a color pair using +the foreground/background colors rather than assign a fixed color pair number, +and return an unused pair to the pool. +.PP +The number of colors may be related to the number of possible color +pairs for a given terminal, or it may not: +.bP +While almost all terminals allow setting the color \fIattributes\fP +independently, +it is unlikely that your terminal allows you to modify the attributes +of a given character cell without rewriting it. +That is, the foreground and background colors are applied as a pair. +.bP +Color pairs are the \fIcurses\fP library's way of managing a color palette +on a terminal. +If the library does not keep track of the \fIcombinations\fP of +colors which are displayed, it will be inefficient. +.IP \(bu 4 +For simple terminal emulators +with only a few dozen color combinations, +it is convenient to use the maximum number of combinations +as the limit on color pairs: +.PP +.RS 8 +.EX +\fBCOLORS\fI * \fBCOLORS\fR +.EE +.RE +.IP \(bu 4 +Terminals which support \fIdefault colors\fP distinct +from \*(``ANSI colors\*('' +add to the possible combinations, producing this total: +.PP +.RS 8 +.EX +\fI( \fBCOLORS\fI + 1 ) * ( \fBCOLORS\fI + 1 )\fR +.EE +.RE +.bP +An application might use up to a few dozen color pairs to +implement a predefined color scheme. +.IP +Beyond that lies in the realm of programs using the foreground +and background colors for \*(``ASCII art\*('' +(or some other non-textual application). +.IP +Also beyond those few dozen pairs, the required size for a table +to represent the combinations grows rapidly with an increasing number of colors. +.IP +These functions allow a developer to let the screen library +manage color pairs. +.SS alloc_pair +The \fBalloc_pair\fP function accepts parameters for +foreground and background color, and +checks if that color combination is already associated with a color pair. +.bP +If the combination already exists, +\fBalloc_pair\fP returns the existing pair. +.bP +If the combination does not exist, +\fBalloc_pair\fP allocates a new color pair and returns that. +.bP +If the table fills up, \fBalloc_pair\fP discards the least-recently +allocated entry using \fBfree_pair\fP and allocates a new color pair. +.PP +All of the color pairs are allocated from a table of possible color pairs. +The size of the table is determined by the terminfo \fBpairs\fP capability. +The table is shared with \fBinit_pair\fP; +in fact \fBalloc_pair\fP calls \fBinit_pair\fP after +updating the \fI\%ncurses\fP library's fast index +to the colors versus color pairs. +.SS find_pair +The \fBfind_pair\fP function accepts parameters for +foreground and background color, and +checks if that color combination is already associated with a color pair, +returning the pair number if it has been allocated. +Otherwise it returns \-1. +.SS free_pair +Marks the given color pair as unused, +i.e., like color pair 0. +.SH RETURN VALUE +The \fBalloc_pair\fP function returns a color pair number in the range +1 through \fBCOLOR_PAIRS\fP\-1, unless it encounters an error updating +its fast index to the color pair values, preventing it from allocating +a color pair. +In that case, it returns \-1. +.PP +The \fBfind_pair\fP function returns a color pair number if the +given color combination has been associated with a color pair, +or \-1 if not. +.PP +Likewise, \fBfree_pair\fP returns \fBOK\fP unless it encounters an +error updating the fast index or if no such color pair is in use. +.SH PORTABILITY +These routines are specific to \fI\%ncurses\fP. +They were not supported on +Version 7, BSD or System V implementations. +It is recommended that +any code depending on them be conditioned using \fB\%NCURSES_VERSION\fP. +.SH AUTHORS +Thomas Dickey +.SH SEE ALSO +\fB\%curs_color\fP(3X) |