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+ * Copyright 2018-2022,2023 Thomas E. Dickey *
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* Author: Thomas E. Dickey
- * @Id: new_pair.3x,v 1.16 2021/06/17 21:26:02 tom Exp @
+ * @Id: new_pair.3x,v 1.44 2023/12/16 20:32:22 tom Exp @
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-<H1 class="no-header">new_pair 3X</H1>
+<H1 class="no-header">new_pair 3x 2023-12-16 ncurses 6.4 Library calls</H1>
<PRE>
-<B><A HREF="new_pair.3X.html">new_pair(3X)</A></B> <B><A HREF="new_pair.3X.html">new_pair(3X)</A></B>
+<STRONG><A HREF="new_pair.3x.html">new_pair(3x)</A></STRONG> Library calls <STRONG><A HREF="new_pair.3x.html">new_pair(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <B>alloc_pair</B>, <B>find_pair</B>, <B>free_pair</B> - new curses color-pair functions
+ <STRONG>alloc_pair</STRONG>, <STRONG>find_pair</STRONG>, <STRONG>free_pair</STRONG> - dynamically allocate <EM>curses</EM> color
+ pairs
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
- <B>#include</B> <B><curses.h></B>
+ <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- <B>int</B> <B>alloc_pair(int</B> <I>fg</I><B>,</B> <B>int</B> <I>bg</I><B>);</B>
- <B>int</B> <B>find_pair(int</B> <I>fg</I><B>,</B> <B>int</B> <I>bg</I><B>);</B>
- <B>int</B> <B>free_pair(int</B> <I>pair</I><B>);</B>
+ <STRONG>int</STRONG> <STRONG>alloc_pair(int</STRONG> <EM>fg</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>bg</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>find_pair(int</STRONG> <EM>fg</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>bg</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>free_pair(int</STRONG> <EM>pair</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- These functions are an extension to the curses library. They permit an
- application to dynamically allocate a color pair using the
- foreground/background colors rather than assign a fixed color pair
+ These functions are an extension to the <EM>curses</EM> 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.
- The number of colors may be related to the number of possible color
+ The number of colors may be related to the number of possible color
pairs for a given terminal, or it may not:
- <B>o</B> While almost all terminals allow setting the color <I>attributes</I>
- independently, it is unlikely that your terminal allows you to
- modify the attributes of a given character cell without rewriting
+ <STRONG>o</STRONG> While almost all terminals allow setting the color <EM>attributes</EM>
+ 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.
- <B>o</B> Color pairs are the curses library's way of managing a color
- palette on a terminal. If the library does not keep track of the
- <I>combinations</I> of colors which are displayed, it will be inefficient.
+ <STRONG>o</STRONG> Color pairs are the <EM>curses</EM> library's way of managing a color
+ palette on a terminal. If the library does not keep track of the
+ <EM>combinations</EM> of colors which are displayed, it will be inefficient.
- <B>o</B> For simple terminal emulators with only a few dozen color
- combinations, it is convenient to use the maximum number of
+ <STRONG>o</STRONG> 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:
- <B>COLORS</B> <I>*</I> <B>COLORS</B>
+ <STRONG>COLORS</STRONG> <EM>*</EM> <STRONG>COLORS</STRONG>
- <B>o</B> Terminals which support <I>default</I> <I>colors</I> distinct from "ANSI colors"
+ <STRONG>o</STRONG> Terminals which support <EM>default</EM> <EM>colors</EM> distinct from "ANSI colors"
add to the possible combinations, producing this total:
- <I>(</I> <B>COLORS</B> <I>+</I> <I>1</I> <I>)</I> <I>*</I> <I>(</I> <B>COLORS</B> <I>+</I> <I>1</I> <I>)</I>
+ <EM>(</EM> <STRONG>COLORS</STRONG> <EM>+</EM> <EM>1</EM> <EM>)</EM> <EM>*</EM> <EM>(</EM> <STRONG>COLORS</STRONG> <EM>+</EM> <EM>1</EM> <EM>)</EM>
- <B>o</B> An application might use up to a few dozen color pairs to implement
+ <STRONG>o</STRONG> An application might use up to a few dozen color pairs to implement
a predefined color scheme.
- Beyond that lies in the realm of programs using the foreground and
- background colors for "ASCII art" (or some other non-textual
+ Beyond that lies in the realm of programs using the foreground and
+ background colors for "ASCII art" (or some other non-textual
application).
Also beyond those few dozen pairs, the required size for a table to
- represent the combinations grows rapidly with an increasing number
+ represent the combinations grows rapidly with an increasing number
of colors.
- These functions allow a developer to let the screen library manage
+ These functions allow a developer to let the screen library manage
color pairs.
</PRE><H3><a name="h3-alloc_pair">alloc_pair</a></H3><PRE>
- The <B>alloc_pair</B> function accepts parameters for foreground and
- background color, and checks if that color combination is already
+ The <STRONG>alloc_pair</STRONG> function accepts parameters for foreground and
+ background color, and checks if that color combination is already
associated with a color pair.
- <B>o</B> If the combination already exists, <B>alloc_pair</B> returns the existing
+ <STRONG>o</STRONG> If the combination already exists, <STRONG>alloc_pair</STRONG> returns the existing
pair.
- <B>o</B> If the combination does not exist, <B>alloc_pair</B> allocates a new color
+ <STRONG>o</STRONG> If the combination does not exist, <STRONG>alloc_pair</STRONG> allocates a new color
pair and returns that.
- <B>o</B> If the table fills up, <B>alloc_pair</B> discards the least-recently
- allocated entry using <B>free_pair</B> and allocates a new color pair.
+ <STRONG>o</STRONG> If the table fills up, <STRONG>alloc_pair</STRONG> discards the least-recently
+ allocated entry using <STRONG>free_pair</STRONG> and allocates a new color pair.
- All of the color pairs are allocated from a table of possible color
- pairs. The size of the table is determined by the terminfo <I>pairs</I>
- capability. The table is shared with <B>init_pair</B>; in fact <B>alloc_pair</B>
- calls <B>init_pair</B> after updating the ncurses library's fast index to the
+ All of the color pairs are allocated from a table of possible color
+ pairs. The size of the table is determined by the terminfo <STRONG>pairs</STRONG>
+ capability. The table is shared with <STRONG>init_pair</STRONG>; in fact <STRONG>alloc_pair</STRONG>
+ calls <STRONG>init_pair</STRONG> after updating the <EM>ncurses</EM> library's fast index to the
colors versus color pairs.
</PRE><H3><a name="h3-find_pair">find_pair</a></H3><PRE>
- The <B>find_pair</B> 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.
+ The <STRONG>find_pair</STRONG> 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.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- The <B>alloc_pair</B> function returns a color pair number in the range 1
- through <B>COLOR_PAIRS</B>-1, unless it encounters an error updating its fast
- index to the color pair values, preventing it from allocating a color
+ The <STRONG>alloc_pair</STRONG> function returns a color pair number in the range 1
+ through <STRONG>COLOR_PAIRS</STRONG>-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.
- The <B>find_pair</B> function returns a color pair number if the given color
+ The <STRONG>find_pair</STRONG> function returns a color pair number if the given color
combination has been associated with a color pair, or -1 if not.
- Likewise, <B>free_pair</B> returns <B>OK</B> unless it encounters an error updating
+ Likewise, <STRONG>free_pair</STRONG> returns <STRONG>OK</STRONG> unless it encounters an error updating
the fast index or if no such color pair is in use.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- These routines are specific to ncurses. They were not supported on
+ These routines are specific to <EM>ncurses</EM>. 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.
+ code depending on them be conditioned using <STRONG>NCURSES_VERSION</STRONG>.
-</PRE><H2><a name="h2-
SEE-ALSO">SEE ALSO</a></H2><PRE>
- <B><A HREF="curs_color.3X.html">curs_color(3X)</A></B>.
+</PRE><H2><a name="h2-
AUTHORS">AUTHORS</a></H2><PRE>
+ Thomas Dickey
-</PRE><H2><a name="h2-
AUTHOR">AUTHOR</a></H2><PRE>
- Thomas Dickey.
+</PRE><H2><a name="h2-
SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>
- <B><A HREF="new_pair.3X.html">new_pair(3X)</A></B>
+ncurses 6.4 2023-12-16 <STRONG><A HREF="new_pair.3x.html">new_pair(3x)</A></STRONG>
</PRE>
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<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-AUTHORS">AUTHORS</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
-<li><a href="#h2-AUTHOR">AUTHOR</a></li>
</ul>
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