.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_pad.3x,v 1.53 2024/01/05 21:46:58 tom Exp $
-.TH curs_pad 3X 2024-01-05 "ncurses 6.4" "Library calls"
+.\" $Id: curs_pad.3x,v 1.65 2024/06/22 22:20:03 tom Exp $
+.TH curs_pad 3X 2024-06-22 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
\fB#include <curses.h>
.PP
\fBWINDOW *newpad(int \fInlines\fP, int \fIncols\fP);
-\fBWINDOW *subpad(WINDOW *\fIorig\fP, int \fInlines\fP, int \fIncols\fP,
+\fBWINDOW *subpad(WINDOW *\fIparent\fP, int \fInlines\fP, int \fIncols\fP,
\fBint \fIbegin_y\fB, int \fIbegin_x\fB);\fR
+.PP
\fBint prefresh(WINDOW *\fIpad\fB, int \fIpminrow\fB, int \fIpmincol\fB,\fR
\fBint \fIsminrow\fB, int \fIsmincol\fB, int \fIsmaxrow\fB, int \fIsmaxcol\fB);\fR
\fBint pnoutrefresh(WINDOW *\fIpad\fB, int \fIpminrow\fB, int \fIpmincol\fB,\fR
\fBint \fIsminrow\fB, int \fIsmincol\fB, int \fIsmaxrow\fB, int \fIsmaxcol\fB);\fR
+.PP
\fBint pechochar(WINDOW *\fIpad\fB, chtype \fIch\fB);\fR
\fBint pecho_wchar(WINDOW *\fIpad\fB, const cchar_t *\fIwch\fB);\fR
.fi
.SH DESCRIPTION
-.SS newpad
-\fB\%newpad\fP creates and returns a pointer to a new pad data structure
-with the given number of lines,
-\fInlines\fP,
-and columns,
-\fIncols\fP.
-A pad is like a window,
+A
+.I curses
+.I pad
+is like a window,
except that it is not restricted by the screen size,
and is not necessarily associated with a particular part of the screen.
Pads can be used when a large window is needed,
-and only a part of the window will be on the screen at one time.
-Automatic refreshes of pads
-(as from scrolling or echoing of input)
-do not occur.
+only part of which is to be visible on the screen.
+Pads are not automatically refreshed by scrolling or input-echoing
+operations.
.PP
-It is not valid to call \fB\%wrefresh\fP with a \fIpad\fP argument;
-call \fB\%prefresh\fP or \fB\%pnoutrefresh\fP instead.
-They require additional parameters to specify the part of the pad to be
-displayed and the location on the screen to be used for the display.
+Pads cannot be refreshed with \fB\%wrefresh\fP(3X);
+use
+.B \%prefresh
+or
+.B \%pnoutrefresh
+instead.
+.SS newpad
+.B \%newpad
+creates and returns a pointer to a new pad data structure
+with the given number of lines,
+.IR nlines ,
+and columns,
+.IR ncols .
.SS subpad
-The \fB\%subpad\fP routine creates and returns a pointer to a subwindow within a
-pad with the given number of lines, \fInlines\fP, and columns, \fIncols\fP.
-Unlike \fB\%subwin\fP, which uses screen coordinates, the window is at position
-(\fIbegin\fR_\fIx\fB,\fR \fIbegin\fR_\fIy\fR) on the pad.
-The window is
-made in the middle of the window \fIorig\fP, so that changes made to one window
-affect both windows.
-During the use of this routine, it will often be
-necessary to call \fB\%touchwin\fP or \fB\%touchline\fP on \fIorig\fP before
-calling \fB\%prefresh\fP.
+.B \%subpad
+creates and returns a pointer to a subwindow within a pad
+with the given number of lines,
+.IR nlines ,
+and columns,
+.IR ncols .
+Unlike \fB\%subwin\fP(3X),
+which uses screen coordinates,
+the new pad is placed at position
+.RI ( begin_y ,
+.IR begin_x )
+relative to its parent.
+Thus,
+changes made to one pad can affect both.
+When operating on a subpad,
+it is often necessary to call \fB\%touchwin\fP(3X) or
+\fB\%touchline\fP(3X) on
+.I parent
+before calling
+.BR \%prefresh .
.SS "prefresh, pnoutrefresh"
-The \fB\%prefresh\fP and \fB\%pnoutrefresh\fP routines are analogous to
-\fB\%wrefresh\fP and \fB\%wnoutrefresh\fP except that they relate to pads instead
-of windows.
-The additional parameters are needed to indicate what part of the
-pad and screen are involved.
+.B \%prefresh
+and
+.B \%pnoutrefresh
+are analogous to \fB\%wrefresh\fP(3X) and \fB\%wnoutrefresh\fP(3X)
+except that they operate on pads rather than windows.
+They require additional parameters are needed to indicate what portions
+of the pad and screen are involved.
.bP
-The \fIpminrow\fP and \fIpmincol\fP parameters specify the upper
-left-hand corner of the rectangle to be displayed in the pad.
+.I pminrow
+and
+.I pmincol
+specify the upper left-hand corner of a rectangular view of the pad.
.bP
-The \fIsminrow\fP,
-\fIsmincol\fP, \fIsmaxrow\fP, and \fIsmaxcol\fP
-parameters specify the edges of the
-rectangle to be displayed on the screen.
+.IR sminrow ,
+.IR smincol ,
+.IR smaxrow ,
+and
+.I smaxcol
+specify the vertices of the rectangle to be displayed on the screen.
.PP
-The lower right-hand corner of the
-rectangle to be displayed in the pad is calculated from the screen coordinates,
+The lower right-hand corner
+of the rectangle to be displayed in the pad
+is calculated from the screen coordinates,
since the rectangles must be the same size.
-Both rectangles must be entirely
-contained within their respective structures.
-Negative values of
-\fIpminrow\fP, \fIpmincol\fP, \fIsminrow\fP, or \fIsmincol\fP are treated as if
-they were zero.
+Both rectangles must be entirely contained
+within their respective structures.
+.I curses
+treats
+negative values of any of these parameters as zero.
.SS pechochar
-The \fB\%pechochar\fP routine is functionally equivalent
-to a call to \fB\%addch\fP
-followed by a call to \fB\%refresh\fP(3X),
-a call to \fB\%waddch\fP followed by a call
-to \fB\%wrefresh\fP, or a call to \fB\%waddch\fP followed by a call to
-\fB\%prefresh\fP.
-The knowledge that only a single character is being output is
-taken into consideration and, for non-control characters, a considerable
-performance gain might be seen by using these routines instead of their
-equivalents.
-In the case of \fB\%pechochar\fP, the last location of the pad on
-the screen is reused for the arguments to \fB\%prefresh\fP.
+.B \%pechochar
+is functionally equivalent to calling \fB\%waddch\fP(3X) followed by
+.BR \%prefresh .
+It suggests to the
+.I curses
+optimizer that only a single character is being output;
+a considerable performance benefit may be thus enjoyed.
+The location of the character
+.I ch
+written to the pad is used to populate the arguments to
+.BR \%prefresh .
.SS pecho_wchar
-The \fB\%pecho_wchar\fP function is the analogous wide-character
-form of \fB\%pechochar\fP.
-It outputs one character to a pad and immediately refreshes the pad.
-It does this by a call to \fB\%wadd_wch\fP followed by a call
-to \fB\%prefresh\fP.
+.B \%pecho_wchar
+is functionally equivalent to calling \fB\%wadd_wch\fP(3X) followed by
+.BR \%prefresh .
+It suggests to the
+.I curses
+optimizer that only a single wide character is being output;
+a considerable performance benefit may be thus enjoyed.
+The location of the character
+.I wch
+written to the pad is used to populate the arguments to
+.BR \%prefresh .
.SH RETURN VALUE
-Functions that return an integer return \fBERR\fP upon failure and
-\fBOK\fP
+Functions that return an integer return
+.B ERR
+upon failure and
+.B OK
(SVr4 specifies only
-\*(``an integer value other than \fBERR\fP\*('')
+\*(``an integer value other than
+.BR ERR \*('')
upon successful completion.
.PP
-Functions that return pointers return \fBNULL\fP on error,
-and set \fB\%errno\fP to \fB\%ENOMEM\fP.
+Functions that return pointers return
+.B NULL
+on error,
+and set
+.I \%errno
+to
+.BR \%ENOMEM "."
.PP
-X/Open Curses does not define any error conditions.
+X/Open Curses does not specify any error conditions.
In this implementation
.RS 3
.TP 5
-\fB\%prefresh\fP and \fB\%pnoutrefresh\fP
-return an error
+.BR prefresh\ and\ pnoutrefresh
+return
+.B ERR
if the window pointer is null, or
if the window is not really a pad or
if the area to refresh extends off-screen or
if the minimum coordinates are greater than the maximum.
.TP 5
-\fBpechochar\fP
-returns an error
-if the window is not really a pad, and the associated call
-to \fB\%wechochar\fP returns an error.
+.B pechochar
+returns
+.B ERR
+if the window is not really a pad,
+and the associated call to
+.B \%wechochar
+returns
+.BR ERR "."
.TP 5
-\fBpecho_wchar\fP
-returns an error
-if the window is not really a pad, and the associated call
-to \fB\%wecho_wchar\fP returns an error.
+.B pecho_wchar
+returns
+.B ERR
+if the window is not really a pad,
+and the associated call to
+.B \%wecho_wchar
+returns
+.BR ERR "."
.RE
.SH NOTES
-\fB\%pechochar\fP may be a macro.
+.B \%pechochar
+may be a macro.
.SH PORTABILITY
-BSD \fIcurses\fP has no \fIpad\fP feature.
+BSD
+.I curses
+has no
+.I pad
+feature.
.PP
SVr2 \fIcurses\fP (1986) provided the \fB\%newpad\fP and related functions,
documenting them in a single line each.
.PP
The two uses may be related.
.PP
-The XSI Curses standard, Issue 4 describes these functions,
+X/Open Curses, Issue 4 describes these functions,
without significant change from the SVr3 documentation.
It describes no error conditions.
The behavior of \fB\%subpad\fP if the parent window is not
projects / ncurses.git / blobdiff