ncurses/man/curs_mouse.3x

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.\" $Id: curs_mouse.3x,v 1.131 2025/11/12 01:06:36 tom Exp $
.TH curs_mouse 3X 2025-11-11 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "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,
\fB\%mmask_t\fP,
\fB\%MEVENT\fP \-
get mouse events in \fIncurses\fR
.SH SYNOPSIS
.nf
\fB#include <curses.h>
.PP
\fI/* data types */
\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
\fI/* functions */
\fBbool has_mouse(void);
.PP
\fBmmask_t mousemask(mmask_t \fInew-mask\fP, mmask_t * \fIold-mask\fP);
.PP
\fBint getmouse(MEVENT * \fIevent\fP);
\fBint ungetmouse(MEVENT * \fIevent\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);
.PP
\fBint mouseinterval(int \fIerval\fB);\fR
.fi
.SH DESCRIPTION
.I \%ncurses
provides an interface to the mouse or other pointing device.
An application can register its interest in such events;
the library then exposes the availability of a mouse event via an
.IR "input character reading function" ":"
this is \fB\%wgetch\fP(3X) in the non-wide character
.I curses
API and \fB\%wget_wch\fP(3X) in the wide character API.
A queue distinct from that used for keyboard events
accumulates the details of mouse events.
The input character reading function
reports the
.B \%KEY_MOUSE
key code when a mouse event is available for collection.
A single mouse event queue serves all windows
associated with the screen.
.PP
The
.I \%MEVENT
structure describes a mouse event.
Its
.I y
and
.I x
coordinates are screen-,
not window-,
relative.
The
.I \%bstate
member has exactly one bit set indicating the event type.
.PP
.I \%ncurses
ignores mouse events when input is in canonical (\*(``cooked\*('') mode,
and produces an error beep when they occur
while the library simulates canonical mode in a window,
as with \fB\%getstr\fP(3X)
(wide-character API users: \fB\%get_wstr\fP(3X)),
which expects a line feed to terminate its input loop.
.SS has_mouse
The terminal type or operating system interface
must support the encoding of mouse events.
.B \%has_mouse
returns
.B TRUE
if
.IR \%ncurses 's
mouse driver initialized successfully,
and
.B FALSE
otherwise.
.SS mousemask
Use
.B \%mousemask
to select the varieties of mouse event your application wishes to
receive.
By default,
.I \%ncurses
reports no mouse events.
.bP
The function returns an updated copy of
.I new-mask
indicating which event types of interest
are reportable by the terminal's mouse protocol.
.IP
If the screen is not initialized,
or the terminal interface does not report mouse events,
.B \%mousemask
returns 0.
.bP
If
.I old-mask
is not a null pointer,
.B \%mousemask
stores the previous value
of the screen's mouse event mask there.
.PP
As a side effect,
setting a zero mouse mask may turn off the mouse cursor;
setting a nonzero mask may turn it on.
Whether this happens is device-dependent.
.SS "Mouse Events"
Several mouse event types may be selected;
construct a mask by logically \*(``or\*(''-ing their values.
.PP
.TS
Lb Lb
Lb Lw(33n)x.
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{
a shift key was down during button state change
T}
BUTTON_CTRL	T{
a control key was down during button state change
T}
BUTTON_ALT	T{
an alt key was down during button state change
T}
ALL_MOUSE_EVENTS	report all button state changes
REPORT_MOUSE_POSITION	report mouse movement
_
.TE
.SS getmouse
When a window is configured to report a non-empty set of event types,
calling the input character reading function on that window may return
.B \%KEY_MOUSE
to indicate availability of an enqueued mouse event.
To read the event data and remove it from the queue,
call
.BR \%getmouse ","
which returns
.B OK
if a mouse event is visible in the given window
and
.B ERR
otherwise.
When
.B \%getmouse
returns
.BR OK ","
it deposits data describing the mouse event in the
.I event
pointer you supply.
A subsequent
.B \%getmouse
call retrieves the next older event from the queue.
.SS ungetmouse
.B \%ungetmouse
behaves analogously to \fB\%ungetch\fP(3X).
It pushes a
.B \%KEY_MOUSE
event onto the screen's input queue,
and
.I event
onto the mouse event queue.
.SS wenclose
.B \%wenclose
returns
.B TRUE
if the pair of screen-relative coordinates
.RI ( y ,
.IR x ")"
is enclosed by the given window
.IR win ","
and
.B FALSE
otherwise.
If
.I win
is a pad,
.B \%wenclose
uses its most recent screen coordinates as specified in
a \fB\%prefresh\fP(3X) or \fB\%pnoutrefresh\fP(3X) call.
.PP
.B \%wenclose
is useful for determining what subset of the screen's windows
encloses the location of a mouse event;
it is otherwise independent of the
.I \%ncurses
mouse API.
.SS wmouse_trafo
.B \%wmouse_trafo
transforms the given pair of coordinate pointers
.RI ( pY ,
.IR pX ")"
from a
.IR win -relative
basis to a screen-relative one or
.IR "vice versa" ","
as
.I to-screen
is
.B TRUE
or
.BR FALSE ","
respectively.
.BR \%stdscr -relative
coordinates are not always identical to screen coordinates:
.I curses
supports reservation of screen lines at the top and/or bottom
for other purposes;
see \fB\%ripoffline\fP(3X) and \fB\%slk_init\fP(3X).
.PP
If
.I to-screen is
.B TRUE
and the pointers
.RI ( pY ,
.IR pX ")"
reference coordinates inside
.IR win ","
.I \%ncurses
updates their values to
.BR \%stdscr -relative
coordinates and returns
.BR TRUE "."
If either
.I pY
or
.I pX
is a null pointer,
or
.RI ( pY ,
.IR pX ")"
is not inside
.IR win ","
.B \%wmouse_trafo
returns
.BR FALSE "."
.PP
If
.I to-screen is
.B FALSE
and the pointers
.RI ( pY ,
.IR pX ")"
reference coordinates inside
.BR stdscr ","
.I \%ncurses
updates their values to
.IR win -relative
coordinates and returns
.BR TRUE "."
If either
.I pY
or
.I pX
is a null pointer,
or
.RI ( pY ,
.IR pX ")"
is not inside
.BR stdscr ","
.B \%wmouse_trafo
returns
.BR FALSE "."
.SS mouse_trafo
.B \%mouse_trafo
applies the
.B \%wmouse_trafo
translation to
.BR \%stdscr "."
If no screen lines are reserved by \fB\%ripoffline\fP(3X) or
\fB\%slk_init\fP(3X),
this is the identity transformation.
.SS mouseinterval
.B \%mouseinterval
sets the maximum time
(in thousandths 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
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,
then no click resolution occurs.
Calling
.B \%mouseinterval(0)
disables click resolution.
.PP
.B \%mouseinterval
returns the previous interval value.
Use
.B \%mouseinterval(\-1)
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 \fBinitscr\fP(3X) or \fBsetupterm\fP(3X).
.SH RETURN VALUE
.BR \%has_mouse ","
.BR \%wenclose ","
.BR \%mouse_trafo ","
and
.B \%wmouse_trafo
return
.B TRUE
or
.B FALSE
as noted above.
.PP
.B \%getmouse
and
.B \%ungetmouse
return
.B ERR
upon failure and
.B OK
upon success.
.PP
.B \%getmouse
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,
or
.bP
no more events remain in the queue.
.PP
.B \%ungetmouse
returns
.B ERR
if the event queue is full.
.PP
.B \%mousemask
returns the mask of reportable events.
.PP
.B \%mouseinterval
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
.B \%MEVENT
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 are not visible to
.I \%ncurses
(and the
.B \%mousemask
function always returns
.BR 0 ")."
.PP
If the terminal type possesses the (nonstandard)
.I \%term\%info
string capability
.BR XM ","
.IR \%ncurses "'s"
.I \%xterm
mouse driver uses it when initializing the terminal for mouse operation.
The default,
if
.B XM
is not found,
corresponds to private mode 1000 of
.IR \%xterm "."
.PP
.RS 3
.EX
\eE[?1000%?%p1%{1}%=%th%el%;
.EE
.RE
.PP
.I \%ncurses
also recognizes
.IR \%xterm 's
newer private mode 1006.
.PP
.RS 3
.EX
\eE[?1006;1000%?%p1%{1}%=%th%el%;
.EE
.RE
.PP
The
.I id
member of the mouse event structure is not presently used;
no terminal type or operating system interface supports reporting events
from distinguishable pointing devices.
If you synthesize an
.IR \%MEVENT ","
use an
.I id
of 0.
.PP
The
.I z
member of the mouse 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
.B \%ALL_MOUSE_EVENTS
class does not include
.BR \%REPORT_MOUSE_POSITION "."
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 are
.I \%ncurses
extensions,
and are not found in SVr4
.IR curses ,
4.4BSD
.IR curses ,
or any other previous
.I curses
implementation.
(SVr4
.I curses
did have a
.I \%getmouse
function,
which took no argument and returned an
.IR "unsigned long" ".)"
.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(3X).
The following values may be specified.
.RS 3
.TP 3
.B 1
has definitions for reserved events.
The mask uses 28 bits.
.TP 3
.B 2
adds definitions for button 5,
removes the definitions for reserved events.
The mask uses 29 bits.
.RE
.SH HISTORY
SVr4 (1989) added mouse support to its 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
.IR \%curses.h "."
.PP
.RS 8
.EX
.nf
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);
.fi
.EE
.RE
.bP
Its \*(``terminfo\*('' manual page lists capabilities for the feature.
.PP
.\" These don't appear 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 Lw(23n)x.
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
.B \%get_mouse
.RB ( getm )
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
.B \%req_mouse_pos
.RB ( reqmp )
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 canonical (\*(``cooked\*('') mode
if they have been enabled by
.BR \%mousemask "."
Instead,
the
.I \%xterm
mouse report sequence appears in the string read.
.PP
An
.I \%ncurses
window must enable \fB\%keypad\fP(3X) to correctly receive mouse event
reports from
.I \%xterm
since they are encoded like function keys.
Set the terminal's
.I \%term\%info
capability
.B \%key_mouse
.RB ( \%kmous )
to \*(``\eE[M\*(''
(the beginning of the response from
.I \%xterm
for mouse clicks).
Other values of
.B \%key_mouse
are permitted under the same assumption \(em
that is,
a mouse report begins with the value of the
.B \%key_mouse
.RB ( \%kmous )
string capability.
.PP
Because there are no standard response sequences that serve to identify
terminals supporting the
.I \%xterm
mouse protocol,
.I \%ncurses
assumes that if
.B \%key_mouse
.RB ( \%kmous )
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.
.I \%ncurses
checks the
.B \%kmous
cap-code first,
allowing use of newer
.I \%xterm
mouse protocols,
such as its private mode 1006.
.SH SEE ALSO
\fB\%curses\fP(3X),
\fB\%curs_inopts\fP(3X),
\fB\%curs_kernel\fP(3X),
\fB\%curs_pad\fP(3X),
\fB\%curs_slk\fP(3X),
\fB\%curs_variables\fP(3X)