mouse(3NCURSES) Library calls mouse(3NCURSES)
NAME
has_mouse, getmouse, ungetmouse, mousemask, wenclose, mouse_trafo,
wmouse_trafo, mouseinterval, mmask_t, MEVENT - get mouse events in
ncurses
SYNOPSIS
#include <curses.h>
/* data types */
typedef unsigned long mmask_t;
typedef struct {
short id; /* ID to distinguish multiple devices */
int x, y, z; /* event coordinates */
mmask_t bstate; /* button state bits */
} MEVENT;
/* functions */
bool has_mouse(void);
mmask_t mousemask(mmask_t new-mask, mmask_t * old-mask);
int getmouse(MEVENT * event);
int ungetmouse(MEVENT * event);
bool wenclose(const WINDOW * win, int y, int x);
bool mouse_trafo(int * pY, int * pX, bool to-screen);
bool wmouse_trafo(const WINDOW * win,
int * pY, int * pX, bool to-screen);
int mouseinterval(int erval);
DESCRIPTION
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 input character reading
function: this is wgetch(3NCURSES) in the non-wide character curses API
and wget_wch(3NCURSES) 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 KEY_MOUSE key code when
a mouse event is available for collection. A single mouse event queue
serves all windows associated with the screen.
The MEVENT structure describes a mouse event. Its y and x coordinates
are screen-, not window-, relative. The bstate member has exactly one
bit set indicating the event type.
ncurses ignores mouse events when input is in canonical (“cooked”) mode,
and produces an error beep when canonical mode is simulated in a window
by a function such as getstr(3NCURSES) that expects a linefeed to termi-
nate its input loop.
has_mouse
The terminal type or operating system interface must support the encod-
ing of mouse events. has_mouse returns TRUE if ncurses's mouse driver
initialized successfully, and FALSE otherwise.
mousemask
Use mousemask to select the varieties of mouse event your application
wishes to receive. By default, ncurses reports no mouse events.
• The function returns an updated copy of new-mask indicating which of
the specified mouse events can be reported.
If the screen is not initialized, or the terminal interface does re-
port mouse events, mousemask returns 0.
• If old-mask is not a null pointer, mousemask stores the previous
value of the screen's mouse event mask there.
As a side effect, setting a zero mouse mask may turn off the mouse cur-
sor; setting a nonzero mask may turn it on. Whether this happens is de-
vice-dependent.
Mouse Events
Several mouse event types may be selected; construct a mask by logically
“or”-ing their values.
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 a shift key was down during button state change
BUTTON_CTRL a control key was down during button state
change
BUTTON_ALT an alt key was down during button state change
ALL_MOUSE_EVENTS report all button state changes
REPORT_MOUSE_POSITION report mouse movement
─────────────────────────────────────────────────────────────────────────
getmouse
Once a class of mouse events has been made visible in a window, calling
the input character reading function on that window may return KEY_MOUSE
as an indicator that a mouse event is enqueued. To read the event data
and pop the event off the queue, call getmouse, which returns OK if a
mouse event is visible in the given window and ERR otherwise. When
getmouse returns OK, it deposits data describing the mouse event in the
event pointer you supply. A subsequent getmouse call retrieves the next
older event from the queue.
ungetmouse
ungetmouse behaves analogously to ungetch(3NCURSES). It pushes a
KEY_MOUSE event onto the screen's input queue, and event onto the mouse
event queue.
wenclose
wenclose returns TRUE if the pair of screen-relative coordinates (y, x)
is enclosed by the given window win, and FALSE otherwise. If win is a
pad, wenclose uses its most recent screen coordinates as specified in a
prefresh(3NCURSES) or pnoutrefresh(3NCURSES) call.
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 ncurses mouse API.
wmouse_trafo
wmouse_trafo transforms the given pair of coordinate pointers (pY, pX)
from a win-relative basis to a screen-relative one or vice versa, as to-
screen is TRUE or FALSE, respectively. stdscr-relative coordinates are
not always identical to screen coordinates: curses supports reservation
of screen lines at the top and/or bottom for other purposes; see
ripoffline(3NCURSES) and slk_init(3NCURSES).
If to-screen is TRUE and the pointers (pY, pX) reference coordinates in-
side win, ncurses updates their values to stdscr-relative coordinates
and returns TRUE. If either pY or pX is a null pointer, or (pY, pX) is
not inside win, wmouse_trafo returns FALSE.
If to-screen is FALSE and the pointers (pY, pX) reference coordinates
inside stdscr, ncurses updates their values to win-relative coordinates
and returns TRUE. If either pY or pX is a null pointer, or (pY, pX) is
not inside stdscr, wmouse_trafo returns FALSE.
mouse_trafo
mouse_trafo applies the wmouse_trafo translation to stdscr. If no
screen lines are reserved by ripoffline(3NCURSES) or slk_init(3NCURSES),
this is the identity transformation.
mouseinterval
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
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”.
Calling mouseinterval(0) disables click resolution. When ncurses de-
tects a mouse event, it awaits further input activity up to this inter-
val, 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 oc-
curs.
This function returns the previous interval value. Use
mouseinterval(-1) to obtain the interval without altering it.
The mouse interval is set to one sixth of a second when the correspond-
ing screen is initialized, e.g., in initscr(3NCURSES) or
setupterm(3NCURSES).
RETURN VALUE
has_mouse, wenclose, mouse_trafo, and wmouse_trafo return TRUE or FALSE
as noted above.
getmouse and ungetmouse return ERR upon failure and OK upon success.
getmouse fails if:
• no mouse driver was initialized,
• the mask of reportable events is zero,
• a mouse event was detected that does not match the mask, or
• no more events remain in the queue.
ungetmouse returns ERR if the event queue is full.
mousemask returns the mask of reportable events.
mouseinterval returns the previous interval value, unless the terminal
was not initialized. In that case, it returns the maximum interval
value (166).
NOTES
The order of the MEVENT structure members is not guaranteed. Additional
fields may be added to the structure in the future.
Under ncurses, these calls are implemented using either xterm's built-in
mouse-tracking API or platform-specific drivers including
• Alessandro Rubini's gpm server
• FreeBSD sysmouse
• OS/2 EMX
If you are using an unsupported configuration, mouse events are not vis-
ible to ncurses (and the mousemask function always returns 0).
If the terminal type possesses the (nonstandard) terminfo string capa-
bility XM, ncurses's xterm mouse driver uses it when initializing the
terminal for mouse operation. The default, if XM is not found, corre-
sponds to private mode 1000 of xterm.
\E[?1000%?%p1%{1}%=%th%el%;
ncurses also recognizes xterm's newer private mode 1006.
\E[?1006;1000%?%p1%{1}%=%th%el%;
The 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 MEVENT, use
an id of 0.
The 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.
The ALL_MOUSE_EVENTS class does not include REPORT_MOUSE_POSITION. They
are distinct. For example, in xterm, wheel/scrolling mice send position
reports as a sequence of presses of buttons 4 or 5 without matching but-
ton-releases.
EXTENSIONS
These functions are ncurses extensions, and are not found in SVr4
curses, 4.4BSD curses, or any other previous curses implementation.
(SVr4 curses did have a getmouse function, which took no argument and
returned an unsigned long.)
PORTABILITY
Applications employing the ncurses mouse extension should condition its
use on the visibility of the NCURSES_MOUSE_VERSION preprocessor macro.
When the interface changes, the macro's value increments. Multiple ver-
sions are available when ncurses is configured; see section “ALTERNATE
CONFIGURATIONS” of ncurses(3NCURSES). The following values may be spec-
ified.
1 has definitions for reserved events. The mask uses 28 bits.
2 adds definitions for button 5, removes the definitions for re-
served events. The mask uses 29 bits.
HISTORY
SVr4 (1989) added mouse support to its variant of xterm(1). It is men-
tioned in a few places, with little supporting documentation.
• Its “libcurses” manual page lists functions for this feature proto-
typed in curses.h.
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);
• Its “terminfo” manual page lists capabilities for the feature.
buttons btns BT Number of buttons on the mouse
get_mouse getm Gm Curses should get button events
key_mouse kmous Km 0631, Mouse event has occurred
mouse_info minfo Mi Mouse status information
req_mouse_pos reqmp RQ Request mouse position report
• The interface made assumptions (as does ncurses) about the escape
sequences sent to and received from the terminal.
For instance, the SVr4 curses library used the get_mouse (getm) ca-
pability 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 req_mouse_pos
(reqmp) capability.
Those features required a terminal program that had been modified to
work with SVr4 curses. They were not part of the X Consortium's
xterm.
When developing the xterm mouse support for 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 PDCurses 2.3 using the SVr4 interface. PDCurses, however, does not
use video terminals, making it unnecessary to be concerned about compat-
ibility with the escape sequences.
BUGS
Mouse events from xterm are not ignored in canonical mode if they have
been enabled by mousemask. Instead, the xterm mouse report sequence ap-
pears in the string read.
An ncurses window must enable keypad(3NCURSES) to correctly receive
mouse event reports from xterm since they are encoded like function
keys. Set the terminal's terminfo capability key_mouse (kmous) to
“\E[M” (the beginning of the response from xterm for mouse clicks).
Other values of key_mouse are permitted under the same assumption, that
is, the report begins with that sequence.
Because there are no standard response sequences that serve to identify
terminals supporting the xterm mouse protocol, ncurses assumes that if
key_mouse (kmous) is defined in the terminal description, or if the ter-
minal type's primary name or aliases contain the string “xterm”, then
the terminal may send mouse events. ncurses checks the kmous cap-code
first, allowing use of newer xterm mouse protocols, such as its private
mode 1006.
SEE ALSO
ncurses(3NCURSES), inopts(3NCURSES), kernel(3NCURSES), pad(3NCURSES),
slk(3NCURSES), curses_variables(3NCURSES)
ncurses 6.5 2025-02-15 mouse(3NCURSES)
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