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.\" $Id: curs_mouse.3x,v 1.96 2024/03/23 20:38:57 tom Exp $
.TH mouse 3NCURSES 2024-03-23 "ncurses 6.4" "Library calls"
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.SH NAME
\fB\%has_mouse\fP,
\fB\%getmouse\fP,
\fB\%ungetmouse\fP,
\fB\%mousemask\fP,
\fB\%wenclose\fP,
\fB\%mouse_trafo\fP,
\fB\%wmouse_trafo\fP,
\fB\%mouseinterval\fP \-
get mouse events in \fIcurses\fR
.SH SYNOPSIS
.nf
\fB#include <curses.h>
.PP
\fBtypedef unsigned long mmask_t;
.PP
\fBtypedef struct {
\fB    short id;         \fI/* ID to distinguish multiple devices */
\fB    int x, y, z;      \fI/* event coordinates */
\fB    mmask_t bstate;   \fI/* button state bits */
\fB} MEVENT;
.PP
\fBbool has_mouse(void);
.PP
\fBint getmouse(MEVENT *\fIevent\fP);
\fBint ungetmouse(MEVENT *\fIevent\fP);
.PP
\fBmmask_t mousemask(mmask_t \fInewmask\fP, mmask_t *\fIoldmask\fP);
.PP
\fBbool wenclose(const WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP);
.PP
\fBbool mouse_trafo(int* \fIpY\fP, int* \fIpX\fP, bool \fIto_screen\fP);
\fBbool wmouse_trafo(const WINDOW* \fIwin\fP,
                  \fBint* \fIpY\fB, int* \fIpX\fB, bool \fIto_screen\fB);\fR
.PP
\fBint mouseinterval(int \fIerval\fB);\fR
.fi
.SH DESCRIPTION
These functions provide an interface to mouse events from
\fB\%ncurses\fP(3NCURSES).
Mouse events are represented by \fB\%KEY_MOUSE\fP
pseudo-key values in the \fB\%wgetch\fP(3NCURSES) input stream.
.SS mousemask
To make mouse events visible, use the \fB\%mousemask\fP function.
This sets the mouse events to be reported.
By default, no mouse events are reported.
.bP
The function returns an updated copy of \fInewmask\fP
to indicate which of the specified mouse events can be reported.
.IP
If the screen has not been initialized,
or if the terminal does not support mouse-events,
this function returns 0.
.bP
If \fIoldmask\fP is non-\fBNULL\fP,
this function fills the indicated location with the previous value of the
current screen's mouse event mask.
.PP
As a side effect, setting a zero mouse mask may turn off the mouse pointer;
setting a nonzero mask may turn it on.
Whether this happens is device-dependent.
.SS "Mouse Events"
Here are the mouse event type masks which may be defined:
.PP
.TS
Lb Lb
Lb Lx.
Name	Description
=
BUTTON1_PRESSED	mouse button 1 down
BUTTON1_RELEASED	mouse button 1 up
BUTTON1_CLICKED	mouse button 1 clicked
BUTTON1_DOUBLE_CLICKED	mouse button 1 double clicked
BUTTON1_TRIPLE_CLICKED	mouse button 1 triple clicked
_
BUTTON2_PRESSED	mouse button 2 down
BUTTON2_RELEASED	mouse button 2 up
BUTTON2_CLICKED	mouse button 2 clicked
BUTTON2_DOUBLE_CLICKED	mouse button 2 double clicked
BUTTON2_TRIPLE_CLICKED	mouse button 2 triple clicked
_
BUTTON3_PRESSED	mouse button 3 down
BUTTON3_RELEASED	mouse button 3 up
BUTTON3_CLICKED	mouse button 3 clicked
BUTTON3_DOUBLE_CLICKED	mouse button 3 double clicked
BUTTON3_TRIPLE_CLICKED	mouse button 3 triple clicked
_
BUTTON4_PRESSED	mouse button 4 down
BUTTON4_RELEASED	mouse button 4 up
BUTTON4_CLICKED	mouse button 4 clicked
BUTTON4_DOUBLE_CLICKED	mouse button 4 double clicked
BUTTON4_TRIPLE_CLICKED	mouse button 4 triple clicked
_
BUTTON5_PRESSED	mouse button 5 down
BUTTON5_RELEASED	mouse button 5 up
BUTTON5_CLICKED	mouse button 5 clicked
BUTTON5_DOUBLE_CLICKED	mouse button 5 double clicked
BUTTON5_TRIPLE_CLICKED	mouse button 5 triple clicked
_
BUTTON_SHIFT	T{
shift was down during button state change
T}
BUTTON_CTRL	T{
control was down during button state change
T}
BUTTON_ALT	T{
alt was down during button state change
T}
ALL_MOUSE_EVENTS	report all button state changes
REPORT_MOUSE_POSITION	report mouse movement
_
.TE
.SS getmouse
Once a class of mouse events has been made visible in a window,
calling the \fB\%wgetch\fP function on that window may return
\fB\%KEY_MOUSE\fP as an indicator that a mouse event has been queued.
To read the event data and pop the event off the queue, call
\fB\%getmouse\fP.
This function will return \fBOK\fP if a mouse event
is actually visible in the given window, \fBERR\fP otherwise.
When \fB\%getmouse\fP returns \fBOK\fP, the data deposited as y and
x in the event structure coordinates will be screen-relative character-cell
coordinates.
The returned state mask will have exactly one bit set to
indicate the event type.
The corresponding data in the queue is marked invalid.
A subsequent call to \fB\%getmouse\fP will retrieve the next older
item from the queue.
.SS ungetmouse
The \fB\%ungetmouse\fP function behaves analogously to \fB\%ungetch\fP.
It pushes
a \fB\%KEY_MOUSE\fP event onto the input queue, and associates with that event
the given state data and screen-relative character-cell coordinates.
.SS wenclose
The \fB\%wenclose\fP function tests whether a given pair of screen-relative
character-cell coordinates is enclosed by a given window, returning \fBTRUE\fP
if it is and \fBFALSE\fP otherwise.
It is useful for determining what subset of
the screen windows enclose the location of a mouse event.
.PP
If the parameter is a pad,
\fB\%wenclose\fP uses the most recent screen coordinates used for
this pad in
\fB\%prefresh\fP(3NCURSES) or
\fB\%pnoutrefresh\fP(3NCURSES).
.SS wmouse_trafo
The \fB\%wmouse_trafo\fP function transforms a given pair of coordinates
from \fB\%stdscr\fP-relative coordinates
to coordinates relative to the given window or vice versa.
The resulting \fB\%stdscr\fP-relative coordinates are not always
identical to screen coordinates due to the mechanism to reserve
lines on top or bottom of the screen for other purposes
(see the \fB\%ripoffline\fP(3NCURSES) and \fB\%slk_init\fP(3NCURSES) calls, for example).
.bP
If the parameter \fIto_screen\fP is \fBTRUE\fP, the pointers
\fIpY, pX\fP must reference the coordinates of a location
inside the window \fIwin\fP.
They are converted to \fB\%stdscr\fP-relative coordinates and returned
through the pointers.
If the conversion was successful, the function returns \fBTRUE\fP.
.IP
If one of the parameters was \fBNULL\fP or the location is
not inside the window, \fBFALSE\fP is returned.
.bP
If \fIto_screen\fP is
\fBFALSE\fP, the pointers \fIpY, pX\fP must reference
\fB\%stdscr\fP-relative coordinates.
They are converted to window-relative coordinates if the
window \fIwin\fP encloses this point.
In this case the function returns \fBTRUE\fP.
.IP
If one of the parameters is \fBNULL\fP or the point is not inside the
window, \fBFALSE\fP is returned.
.PP
The referenced coordinates
are only replaced by the converted coordinates if the transformation was
successful.
.SS mouse_trafo
The \fB\%mouse_trafo\fP function performs the same translation
as \fB\%wmouse_trafo\fP,
using \fB\%stdscr\fP for \fIwin\fP.
.SS mouseinterval
The \fB\%mouseinterval\fP function sets the maximum time
(in thousands of a second)
that can elapse between press and release events for them to
be resolved as a
.IR click .
An application might interpret button press and release events separated
by more than the mouse interval as a \*(``long press\*('',
or,
with motion,
as a \*(``drag\*(''.
.PP
Calling \fB\%mouseinterval(0)\fP disables click resolution.
When
.I \%ncurses
detects a mouse event,
it awaits further input activity up to this interval,
and then checks for a subsequent mouse event which can be combined
with the first event.
If the timeout expires without input activity
(which would happen with a zero interval),
then no click resolution will occur.
.PP
This function returns the previous interval value.
Use \fB\%mouseinterval(\-1)\fP to obtain the interval without altering it.
.PP
The mouse interval is set to one sixth of a second
when the corresponding screen is initialized,
e.g., in \fB\%initscr\fP(3NCURSES) or \fB\%setupterm\fP(3NCURSES).
.SS has_mouse
The \fB\%has_mouse\fP function returns \fBTRUE\fP if the mouse driver
has been successfully initialized,
and \fBFALSE\fP otherwise.
.PP
Mouse events are ignored when input is in cooked mode, and
cause an error beep when cooked mode is being simulated in a window by a
function such as \fB\%getstr\fP that expects a linefeed for input-loop
termination.
.SH RETURN VALUE
\fB\%has_mouse\fP,
\fB\%wenclose\fP,
\fB\%mouse_trafo\fP,
and
\fB\%wmouse_trafo\fP
return \fBTRUE\fP or \fBFALSE\fP as noted above.
.PP
\fB\%getmouse\fP and \fB\%ungetmouse\fP
return \fBERR\fP upon failure and \fBOK\fP upon success.
.PP
\fB\%getmouse\fP fails if:
.bP
no mouse driver was initialized,
.bP
the mask of reportable events is zero,
.bP
a mouse event was detected that does not match the mask,
.bP
or if no more events remain in the queue.
.PP
\fB\%ungetmouse\fP returns an error if the event queue is full.
.PP
\fB\%mousemask\fP
returns the mask of reportable events.
.PP
\fB\%mouseinterval\fP
returns the previous interval value, unless
the terminal was not initialized.
In that case, it returns the maximum interval value (166).
.SH NOTES
The order of the \fB\%MEVENT\fP structure members is not guaranteed.
Additional fields may be added to the structure in the future.
.PP
Under
.IR \%ncurses ,
these calls are implemented using either
.IR \%xterm 's
built-in mouse-tracking API or
platform-specific drivers including
.RS 3
.bP
Alessandro Rubini's gpm server
.bP
FreeBSD sysmouse
.bP
OS/2 EMX
.RE
.PP
If you are using an unsupported configuration,
mouse events will not be visible to
\fI\%ncurses\fP (and the \fB\%mousemask\fP function will always
return \fB0\fP).
.PP
If the
.I \%term\%info
entry contains a \fBXM\fP string,
this is used in the
.I \%xterm
mouse driver to control the
way the terminal is initialized for mouse operation.
The default, if \fBXM\fP is not found,
corresponds to private mode 1000 of
.I \%xterm:
.PP
.RS 3
\eE[?1000%?%p1%{1}%=%th%el%;
.RE
.PP
The mouse driver also recognizes a newer
.I \%xterm
private mode 1006,
e.g.,
.PP
.RS 3
\eE[?1006;1000%?%p1%{1}%=%th%el%;
.RE
.PP
The \fIz\fP member in the event structure is not presently used.
It is intended
for use with touch screens (which may be pressure-sensitive) or with
3D-mice/trackballs/power gloves.
.PP
The \fB\%ALL_MOUSE_EVENTS\fP class does not
include \fB\%REPORT_MOUSE_POSITION\fP.
They are distinct.
For example,
in
.IR \%xterm ,
wheel/scrolling mice send position reports as a sequence of
presses of buttons 4 or 5 without matching button-releases.
.SH EXTENSIONS
These functions were designed for
\fB\%ncurses\fP(3NCURSES),
and are not found in SVr4
.IR curses ,
4.4BSD
.IR curses ,
or any other previous curses implementation.
(SVr4
.I curses
did have a
.I \%getmouse
function,
which took no argument and returned a different type.)
.SH PORTABILITY
Applications employing the
.I \%ncurses
mouse extension should condition its use on the visibility of the
.B \%NCURSES_MOUSE_VERSION
preprocessor macro.
When the interface changes,
the macro's value increments.
Multiple versions are available when
.I \%ncurses
is configured;
see section \*(``ALTERNATE CONFIGURATIONS\*('' of \fB\%ncurses\fP(3NCURSES).
The following values may be specified.
.RS 3
.TP 3
1
has definitions for reserved events.
The mask uses 28 bits.
.TP 3
2
adds definitions for button 5,
removes the definitions for reserved events.
The mask uses 29 bits.
.RE
.PP
SVr4
.I curses
had support for the mouse in a variant of \fI\%xterm\fP(1).
It is mentioned in a few places,
with little supporting documentation.
.bP
Its \*(``libcurses\*('' manual page lists functions for this feature
prototyped in \fI\%curses.h\fP.
.PP
.RS 8
.EX
extern int mouse_set(long int);
extern int mouse_on(long int);
extern int mouse_off(long int);
extern int request_mouse_pos(void);
extern int map_button(unsigned long);
extern void wmouse_position(WINDOW *, int *, int *);
extern unsigned long getmouse(void), getbmap(void);
.EE
.RE
.bP
Its \*(``terminfo\*('' manual page lists capabilities for the feature.
.\" These don't appear in in the SVID 4th edition, Volume 3,
.\" terminfo(TI_ENV) man page.  They can be found in, e.g., the "z/OS
.\" V1R1.0 C Curses" book, Chapter 17, pp. 179-186 (PDF 213-220).
.RS 8
.TS
Lb Lb Lb Lx.
buttons	btns	BT	T{
Number of buttons on the mouse
T}
get_mouse	getm	Gm	T{
Curses should get button events
T}
key_mouse	kmous	Km	T{
0631, Mouse event has occurred
T}
mouse_info	minfo	Mi	T{
Mouse status information
T}
req_mouse_pos	reqmp	RQ	T{
Request mouse position report
T}
.TE
.RE
.bP
The interface made assumptions
(as does
.IR \%ncurses )
about the escape sequences sent to and received from the terminal.
.IP
For instance,
the SVr4
.I curses
library used the \fB\%get_mouse\fP capability to tell the terminal which
mouse button events it should send,
passing the mouse-button bit mask to the terminal.
Also, it could ask the terminal
where the mouse was using the \fB\%req_mouse_pos\fP capability.
.IP
Those features required a terminal program that had been modified
to work with SVr4
.IR curses .
They were not part of the X Consortium's
.IR \%xterm .
.PP
When developing the
.I \%xterm
mouse support for
.I \%ncurses
in September 1995,
Eric Raymond was uninterested in using the same interface due to its
lack of documentation.
Later, in 1998, Mark Hesseling provided support in
.I \%PDCurses
2.3 using the SVr4 interface.
.IR \%PDCurses ,
however,
does not use video terminals,
making it unnecessary to be concerned about compatibility with the
escape sequences.
.SH BUGS
Mouse events from
.I \%xterm
are
.I not
ignored in cooked mode if they have been enabled by \fB\%mousemask\fP.
Instead,
the
.I \%xterm
mouse report sequence appears in the string read.
.PP
Mouse event reports from
.I \%xterm
are not detected correctly in a window with keypad application mode
disabled,
since they are interpreted as a variety of function key.
Set the terminal's
.I \%term\%info
capability \fB\%kmous\fP to \*(``\eE[M\*(''
(the beginning of the response from
.I \%xterm
for mouse clicks).
Other values of \fB\%kmous\fP are permitted under the same assumption,
that is,
the report begins with that sequence.
.PP
Because there are no standard response sequences that serve to identify
terminals supporting the
.I \%xterm
mouse protocol,
.I \%ncurses
assumes that if \fB\%kmous\fP is defined in the terminal description,
or if the terminal type's primary name or aliases contain the string
\%\*(``xterm\*('',
then the terminal may send mouse events.
The \fB\%kmous\fP capability is checked first,
allowing use of newer
.I \%xterm
mouse protocols,
such as its private mode 1006.
.SH SEE ALSO
\fB\%ncurses\fP(3NCURSES),
\fB\%inopts\fP(3NCURSES),
\fB\%kernel\fP(3NCURSES),
\fB\%pad\fP(3NCURSES),
\fB\%slk\fP(3NCURSES),
\fB\%curses_variables\fP(3NCURSES)