.\"	$NetBSD: curses_window.3,v 1.17 2024/10/13 14:56:30 rillig Exp $
.\"
.\" Copyright (c) 2002
.\"	Brett Lymn (blymn@NetBSD.org, brett_lymn@yahoo.com.au)
.\"
.\" This code is donated to the NetBSD Foundation by the Author.
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.Dd October 13, 2024
.Dt CURSES_WINDOW 3
.Os
.Sh NAME
.Nm curses_window ,
.Nm copywin ,
.Nm dupwin ,
.Nm delwin ,
.Nm derwin ,
.Nm mvwin ,
.Nm mvderwin ,
.Nm newwin ,
.Nm overlay ,
.Nm overwrite ,
.Nm subwin ,
.Nm wresize
.Nd curses window routines
.Sh LIBRARY
.Lb libcurses
.Sh SYNOPSIS
.In curses.h
.Ft int
.Fo copywin
.Fa "const WINDOW *source"
.Fa "WINDOW *dest"
.Fa "int sminrow"
.Fa "int smincol"
.Fa "int dminrow"
.Fa "int dmincol"
.Fa "int dmaxrow"
.Fa "int dmaxcol"
.Fa "int overlay"
.Fc
.Ft WINDOW *
.Fn dupwin "WINDOW *win"
.Ft WINDOW *
.Fn derwin "WINDOW *win" "int lines" "int cols" "int y" "int x"
.Ft int
.Fn delwin "WINDOW *win"
.Ft int
.Fn mvwin "WINDOW *win" "int y" "int x"
.Ft int
.Fn mvderwin "WINDOW *win" "int y" "int x"
.Ft WINDOW *
.Fn newwin "int lines" "int cols" "int begin_y" "int begin_x"
.Ft WINDOW *
.Fn subwin "WINDOW *win" "int lines" "int cols" "int begin_y" "int begin_x"
.Ft int
.Fn overlay "WINDOW *source" "WINDOW *dest"
.Ft int
.Fn overwrite "WINDOW *source" "WINDOW *dest"
.Ft int
.Fn wresize "WINDOW *win" "int lines" "int cols"
.Sh DESCRIPTION
These functions create, modify and delete windows on the current screen.
.Pp
The contents of a window may be copied to another window by using the
.Fn copywin
function, a section of the destination window
.Fa dest
bounded by
.Fa (dminrow ,
.Fa dmincol )
and
.Fa (dmaxrow ,
.Fa dmaxcol )
will be overwritten with the contents of the window
.Fa source
starting at the coordinates
.Fa (sminrow ,
.Fa smincol ) .
If the
.Fa overlay
flag is
.Dv TRUE
then only non-blank characters from
.Fa source
will be copied to
.Fa dest ,
if
.Fa overlay
is
.Dv FALSE
then all characters from
.Fa source
will be copied to
.Fa dest .
If the bounding rectangles of either the source or the destination
windows lay outside the maximum size of the respective windows then
the size of the window copied will be adjusted to be within the bounds
of both the source and destination windows.
.Pp
The
.Fn dupwin
function creates an exact duplicate of
.Fa win
and returns a pointer to it.
.Pp
Calling
.Fn derwin
will create a subwindow of
.Fa win
in the same manner as
.Fn subwin
excepting that the starting column and row
.Fa y ,
.Fa x
are relative to the parent window origin.
.Pp
A window may deleted and all resources freed by calling the
.Fn delwin
function with the pointer to the window to be deleted in
.Fa win .
If
.Fa win
is
.Dv NULL ,
then no action occurs.
.Pp
A window can be moved to a new position by calling the
.Fn mvwin
function.
The
.Fa y
and
.Fa x
positions are the new origin of the window on the screen.
If the new position would cause the any part of the window to lie outside
the screen, it is an error and the window is not moved.
.Pp
A mapping of a region relative to the parent window may be created by
calling the
.Fn mvderwin
function, the
.Fa y
and
.Fa x
positions are relative to the origin of the parent window.
The screen offset of
.Fa win
is not updated, the characters beginning at
.Fa y ,
.Fa x
for the area the size of
.Fa win
will be displayed at the screen offset of
.Fa win .
If the given window in
.Fa win
is not a subwindow then an error will be returned.
If the new position would cause the any part of the window to lie outside
the parent window, it is an error and the mapping is not updated.
.Pp
The
.Fn newwin
function creates a new window of size
.Fa lines ,
.Fa cols
with an origin at
.Fa begin_y ,
.Fa begin_x .
If
.Fa lines
is less than or equal to zero then the number of rows
for the window is set to
.Dv LINES -
.Fa begin_x
+
.Fa lines .
Similarly if
.Fa cols
is less than or equal to zero then the number of columns
for the window is set to
.Dv COLS -
.Fa begin_y
+
.Fa cols .
.Pp
.Fn subwin
is similar to
.Fn newwin
excepting that the size of the subwindow is bounded by the parent
window
.Fa win .
The subwindow shares internal data structures with the parent window
and will be refreshed when the parent window is refreshed.
The subwindow inherits the background character and attributes of the
parent window.
.Pp
The
.Fn overlay
function copies the contents of the source window
.Fa source
to the destination window
.Fa dest ,
only the characters that are not the background character in the
source window are copied to the destination.
The windows need not be the same size, only the overlapping portion of both
windows will be copied.
The
.Fn overwrite
function performs the same functions as
.Fn overlay
excepting that characters from the source window are copied to the
destination without exception.
.Pp
.Fn wresize
resizes the specified window to the new number of lines and columns
given, all internal curses structures are resized.
Any subwindows of the specified window will also be resized if any part
of them falls outside the new parent window size.
The application must redraw the window after it has been resized.
Note that
.Dv curscr
and
.Dv stdscr
can not be resized to be larger than the size of the screen.
.Sh RETURN VALUES
Functions returning pointers will return
.Dv NULL
if an error is detected.
The functions that return an int will return one of the following
values:
.Pp
.Bl -tag -width ERR -compact
.It Er OK
The function completed successfully.
.It Er ERR
An error occurred in the function.
.El
.Sh SEE ALSO
.Xr curses_fileio 3 ,
.Xr curses_pad 3 ,
.Xr curses_screen 3
.Sh STANDARDS
The
.Nx
Curses library complies with the X/Open Curses specification, part of the
Single Unix Specification.
.Sh HISTORY
The Curses package appeared in
.Bx 4.0 .