.\"***************************************************************************
-.\" Copyright 2018-2021,2022 Thomas E. Dickey *
+.\" Copyright 2018-2022,2023 Thomas E. Dickey *
.\" Copyright 1998-2015,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\"
.\" Author: Thomas E. Dickey 1996-on
.\"
-.\" $Id: resizeterm.3x,v 1.31 2022/02/12 20:07:29 tom Exp $
-.TH resizeterm 3X ""
+.\" $Id: resizeterm.3x,v 1.40 2023/09/16 23:38:39 tom Exp $
+.TH resizeterm 3X 2023-09-16 "ncurses 6.4" "Library calls"
.de bP
.ie n .IP \(bu 4
.el .IP \(bu 2
..
.SH NAME
-\fBis_term_resized\fP,
-\fBresize_term\fP,
-\fBresizeterm\fP \- change the curses terminal size
+\fB\%is_term_resized\fP,
+\fB\%resize_term\fP,
+\fB\%resizeterm\fP \-
+manage the terminal dimensions understood by \fIcurses\fR
.SH SYNOPSIS
\fB#include <curses.h>\fP
.sp
.br
\fBint resizeterm(int \fIlines\fB, int \fIcolumns\fB);\fR
.SH DESCRIPTION
-.PP
This is an extension to the curses library.
It provides callers with a hook into the \fBncurses\fP data to resize windows,
-primarily for use by programs running in an X Window terminal (e.g., xterm).
-.SS resizeterm
+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:
+.bP
+Curses windows cannot extend outside the screen.
+If the terminal is shrunk, curses windows must be shrunk to fit.
+.bP
+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.
+.PP
+If the calling program has not set up a handler for \fBSIGWINCH\fP
+when it initializes \fBncurses\fP
+(e.g., using \fBinitscr\fP(3X) or \fBnewterm\fP(3X)),
+then \fBncurses\fP sets a handler for \fBSIGWINCH\fP which notifies
+the library when a window-size event has occurred.
+The library checks for this notification
+.bP
+when reading input data,
+.bP
+when implicitly resuming program mode
+(e.g., between \fBendwin\fP(3X) and \fBwrefresh\fP(3X)),
+and
+.bP
+when explicitly resuming program mode in \fBrestartterm\fP(3X).
.PP
+When the library has found that the terminal's window-size has
+changed, it calls \fBresizeterm\fP to update its data structures.
+.PP
+An application which establishes its own \fBSIGWINCH\fP handler
+can call \fBresizeterm\fP, but in that case, the library will not
+see \fBSIGWINCH\fP, and proper layout will rely upon the application.
+.SH FUNCTIONS
+.SS resizeterm
The function \fBresizeterm\fP resizes the standard and current windows
+(i.e., \fBstdscr\fP and \fBcurscr\fP)
to the specified dimensions, and adjusts other bookkeeping data used by
the \fBncurses\fP library that record the window dimensions
such as the \fBLINES\fP and \fBCOLS\fP variables.
.SS resize_term
-.PP
-Most of the work is done by the inner function \fBresize_term\fP.
+Most of the work for \fBresizeterm\fP is
+done by the inner function \fBresize_term\fP.
The outer function \fBresizeterm\fP adds bookkeeping
for the \fBSIGWINCH\fP handler,
as well as repainting the soft-key area (see \fBslk_touch\fP(3X)).
.PP
-When resizing the windows,
-\fBresize_term\fP blank-fills the areas that are extended.
-The calling application should fill in these areas with appropriate data.
-.PP
The \fBresize_term\fP function attempts to resize all windows.
-However, due to the calling convention of pads,
-it is not possible to resize these
-without additional interaction with the application.
+This helps with simple applications.
+However:
+.bP
+It is not possible to automatically resize pads.
+.bP
+Applications which have complicated layouts should check for
+\fBKEY_RESIZE\fP returned from \fBwgetch\fP,
+and adjust their layout, e.g., using \fBwresize\fP and \fBmvwin\fP,
+or by recreating the windows.
.PP
When resizing windows, \fBresize_term\fP recursively adjusts subwindows,
keeping them within the updated parent window's limits.
extending to the corresponding limit, regardless of whether the
screen has shrunk or grown.
.SS is_term_resized
-.PP
A support function \fBis_term_resized\fP is provided so that applications
can check if the \fBresize_term\fP function would modify the window structures.
It returns \fBTRUE\fP if the windows would be modified,
.bP
on receipt of a \fBSIGWINCH\fP, the handler sets a flag
.bP
-which is tested in \fBwgetch\fP(3X) and \fBdoupdate\fP,
+which is tested in
+\fBwgetch\fP(3X),
+\fBdoupdate\fP(3X) and
+\fBrestartterm\fP(3X),
.bP
in turn, calling the \fBresizeterm\fP function,
.bP
Thus, even if a \fBSIGWINCH\fP is received,
no screen size change may be recorded.
.SH PORTABILITY
-.PP
It is possible to resize the screen with SVr4 curses,
by
.bP
projects / ncurses.git / blobdiff