-<!--
+<!--
****************************************************************************
- * Copyright (c) 1998-2015,2017 Free Software Foundation, Inc. *
+ * Copyright 2018-2021,2022 Thomas E. Dickey *
+ * Copyright 1998-2015,2017 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. *
****************************************************************************
* Author: Thomas E. Dickey 1996-on
- * @Id: resizeterm.3x,v 1.24 2017/11/18 23:47:37 tom Exp @
+ * @Id: resizeterm.3x,v 1.32 2022/02/20 00:32:18 tom Exp @
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<H1 class="no-header">resizeterm 3x</H1>
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- <STRONG>bool</STRONG> <STRONG>is_term_resized(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
- <STRONG>int</STRONG> <STRONG>resize_term(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
- <STRONG>int</STRONG> <STRONG>resizeterm(int</STRONG> <STRONG>lines,</STRONG> <STRONG>int</STRONG> <STRONG>columns);</STRONG>
+ <STRONG>bool</STRONG> <STRONG>is_term_resized(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>resize_term(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>resizeterm(int</STRONG> <EM>lines</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>columns</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
This is an extension to the curses library. It provides callers with a
- hook into the <STRONG>ncurses</STRONG> data to resize windows, primarily for use by pro-
- grams running in an X Window terminal (e.g., xterm).
+ hook into the <STRONG>ncurses</STRONG> data to resize windows, primarily for use by
+ programs running in an X Window terminal (e.g., xterm) when the
+ terminal's screen size is changed by the user:
+
+ <STRONG>o</STRONG> Curses windows cannot extend outside the screen. If the terminal
+ is shrunk, curses windows must be shrunk to fit.
+
+ <STRONG>o</STRONG> If the terminal is stretched, rows and/or columns can be added to
+ existing windows. The added cells should match the current
+ attributes of the windows.
+
+ If the calling program has not set up a handler for <STRONG>SIGWINCH</STRONG> when it
+ initializes <STRONG>ncurses</STRONG> (e.g., using <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> or <STRONG><A HREF="curs_initscr.3x.html">newterm(3x)</A></STRONG>), then
+ <STRONG>ncurses</STRONG> sets a handler for <STRONG>SIGWINCH</STRONG> which notifies the library when a
+ window-size event has occurred. The library checks for this
+ notification
+
+ <STRONG>o</STRONG> when reading input data,
+
+ <STRONG>o</STRONG> when implicitly resuming program mode (e.g., between <STRONG><A HREF="curs_initscr.3x.html">endwin(3x)</A></STRONG> and
+ <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>), and
+
+ <STRONG>o</STRONG> when explicitly resuming program mode in <STRONG><A HREF="curs_terminfo.3x.html">restartterm(3x)</A></STRONG>.
+ When the library has found that the terminal's window-size has changed,
+ it calls <STRONG>resizeterm</STRONG> to update its data structures.
+
+ An application which establishes its own <STRONG>SIGWINCH</STRONG> handler can call
+ <STRONG>resizeterm</STRONG>, but in that case, the library will not see <STRONG>SIGWINCH</STRONG>, and
+ proper layout will rely upon the application.
+
+
+</PRE><H2><a name="h2-FUNCTIONS">FUNCTIONS</a></H2><PRE>
</PRE><H3><a name="h3-resizeterm">resizeterm</a></H3><PRE>
- The function <STRONG>resizeterm</STRONG> resizes the standard and current windows to the
- specified dimensions, and adjusts other bookkeeping data used by the
- <STRONG>ncurses</STRONG> library that record the window dimensions such as the <STRONG>LINES</STRONG> and
- <STRONG>COLS</STRONG> variables.
+ The function <STRONG>resizeterm</STRONG> resizes the standard and current windows (i.e.,
+ <STRONG>stdscr</STRONG> and <STRONG>curscr</STRONG>) to the specified dimensions, and adjusts other
+ bookkeeping data used by the <STRONG>ncurses</STRONG> library that record the window
+ dimensions such as the <STRONG>LINES</STRONG> and <STRONG>COLS</STRONG> variables.
</PRE><H3><a name="h3-resize_term">resize_term</a></H3><PRE>
- Most of the work is done by the inner function <STRONG>resize_term</STRONG>. The outer
- function <STRONG>resizeterm</STRONG> adds bookkeeping for the <STRONG>SIGWINCH</STRONG> handler. When
- resizing the windows, <STRONG>resize_term</STRONG> blank-fills the areas that are
- extended. The calling application should fill in these areas with
- appropriate data. The <STRONG>resize_term</STRONG> function attempts to resize all win-
- dows. However, due to the calling convention of pads, it is not possi-
- ble to resize these without additional interaction with the applica-
- tion.
+ Most of the work for <STRONG>resizeterm</STRONG> is done by the inner function
+ <STRONG>resize_term</STRONG>. The outer function <STRONG>resizeterm</STRONG> adds bookkeeping for the
+ <STRONG>SIGWINCH</STRONG> handler, as well as repainting the soft-key area (see
+ <STRONG><A HREF="curs_slk.3x.html">slk_touch(3x)</A></STRONG>).
+
+ The <STRONG>resize_term</STRONG> function attempts to resize all windows. This helps
+ with simple applications. However:
+
+ <STRONG>o</STRONG> It is not possible to automatically resize pads.
+
+ <STRONG>o</STRONG> Applications which have complicated layouts should check for
+ <STRONG>KEY_RESIZE</STRONG> returned from <STRONG>wgetch</STRONG>, and adjust their layout, e.g.,
+ using <STRONG>wresize</STRONG> and <STRONG>mvwin</STRONG>, or by recreating the windows.
+
+ When resizing windows, <STRONG>resize_term</STRONG> recursively adjusts subwindows,
+ keeping them within the updated parent window's limits. If a top-level
+ window happens to extend to the screen's limits, then on resizing the
+ window, <STRONG>resize_term</STRONG> will keep the window extending to the corresponding
+ limit, regardless of whether the screen has shrunk or grown.
</PRE><H3><a name="h3-is_term_resized">is_term_resized</a></H3><PRE>
A support function <STRONG>is_term_resized</STRONG> is provided so that applications can
- check if the <STRONG>resize_term</STRONG> function would modify the window structures.
+ check if the <STRONG>resize_term</STRONG> function would modify the window structures.
It returns <STRONG>TRUE</STRONG> if the windows would be modified, and <STRONG>FALSE</STRONG> otherwise.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- Except as noted, these functions return the integer <STRONG>ERR</STRONG> upon failure
+ Except as noted, these functions return the integer <STRONG>ERR</STRONG> upon failure
and <STRONG>OK</STRONG> on success. They will fail if either of the dimensions are less
- than or equal to zero, or if an error occurs while (re)allocating mem-
- ory for the windows.
+ than or equal to zero, or if an error occurs while (re)allocating
+ memory for the windows.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- While these functions are intended to be used to support a signal han-
- dler (i.e., for <STRONG>SIGWINCH</STRONG>), care should be taken to avoid invoking them
- in a context where <STRONG>malloc</STRONG> or <STRONG>realloc</STRONG> may have been interrupted, since
- it uses those functions.
+ While these functions are intended to be used to support a signal
+ handler (i.e., for <STRONG>SIGWINCH</STRONG>), care should be taken to avoid invoking
+ them in a context where <STRONG>malloc</STRONG> or <STRONG>realloc</STRONG> may have been interrupted,
+ since it uses those functions.
If ncurses is configured to supply its own <STRONG>SIGWINCH</STRONG> handler,
<STRONG>o</STRONG> on receipt of a <STRONG>SIGWINCH</STRONG>, the handler sets a flag
- <STRONG>o</STRONG> which is tested in <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG> and <STRONG>doupdate</STRONG>,
+ <STRONG>o</STRONG> which is tested in <STRONG><A HREF="curs_getch.3x.html">wgetch(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">doupdate(3x)</A></STRONG> and <STRONG><A HREF="curs_terminfo.3x.html">restartterm(3x)</A></STRONG>,
<STRONG>o</STRONG> in turn, calling the <STRONG>resizeterm</STRONG> function,
<STRONG>o</STRONG> which <STRONG>ungetch</STRONG>'s a <STRONG>KEY_RESIZE</STRONG> which will be read on the next call to
<STRONG>wgetch</STRONG>.
- The <STRONG>KEY_RESIZE</STRONG> alerts an application that the screen size has
- changed, and that it should repaint special features such as pads
+ The <STRONG>KEY_RESIZE</STRONG> alerts an application that the screen size has
+ changed, and that it should repaint special features such as pads
that cannot be done automatically.
Calling <STRONG>resizeterm</STRONG> or <STRONG>resize_term</STRONG> directly from a signal handler is
- unsafe. This indirect method is used to provide a safe way to
+ unsafe. This indirect method is used to provide a safe way to
resize the ncurses data structures.
- If the environment variables <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> are set, this overrides
- the library's use of the window size obtained from the operating sys-
- tem. Thus, even if a <STRONG>SIGWINCH</STRONG> is received, no screen size change may
- be recorded.
+ If the environment variables <STRONG>LINES</STRONG> or <STRONG>COLUMNS</STRONG> are set, this overrides
+ the library's use of the window size obtained from the operating
+ system. Thus, even if a <STRONG>SIGWINCH</STRONG> is received, no screen size change
+ may be recorded.
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
Doing that clears the screen and is visually distracting.
- This extension of ncurses was introduced in mid-1995. It was adopted
+ This extension of ncurses was introduced in mid-1995. It was adopted
in NetBSD curses (2001) and PDCurses (2003).
</PRE><H2><a name="h2-AUTHOR">AUTHOR</a></H2><PRE>
- Thomas Dickey (from an equivalent function written in 1988 for BSD
+ Thomas Dickey (from an equivalent function written in 1988 for BSD
curses).
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
-<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
+<li><a href="#h2-FUNCTIONS">FUNCTIONS</a>
<ul>
<li><a href="#h3-resizeterm">resizeterm</a></li>
<li><a href="#h3-resize_term">resize_term</a></li>