NAME

has_mouse, getmouse, ungetmouse, mousemask, wenclose, mouse_trafo, wmouse_trafo, mouseinterval - get mouse events in curses

SYNOPSIS

#include <ncurses/curses.h>

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;

bool has_mouse(void);

mmask_t mousemask(mmask_t newmask, mmask_t *oldmask);

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

These functions provide an interface to mouse events from ncurses(3X). Mouse events are represented by KEY_MOUSE pseudo-key values in the wgetch(3X) input stream.

has_mouse

The has_mouse function returns TRUE if the mouse driver has been successfully initialized, and FALSE otherwise.

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 getstr that expects a linefeed for input-loop termination.

mousemask

To make mouse events visible, use the mousemask function. This sets the mouse events to be reported. By default, no mouse events are reported.

•: The function returns an updated copy of newmask to indicate which of the specified mouse events can be reported.

: If the screen has not been initialized, or if the terminal does not support mouse-events, this function returns 0.

•: If oldmask is non-NULL, this function fills the indicated location with the previous value of the current screen's mouse event mask.

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.

Mouse Events

Here are the mouse event type masks which may be defined:

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	shift was down during button state change
BUTTON_CTRL	control was down during button state change
BUTTON_ALT	alt 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 wgetch function on that window may return KEY_MOUSE as an indicator that a mouse event has been queued. To read the event data and pop the event off the queue, call getmouse. This function will return OK if a mouse event is actually visible in the given window, ERR otherwise. When getmouse returns OK, 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 getmouse will retrieve the next older item from the queue.

ungetmouse

The ungetmouse function behaves analogously to ungetch. It pushes a KEY_MOUSE event onto the input queue, and associates with that event the given state data and screen-relative character-cell coordinates.

wenclose

The wenclose function tests whether a given pair of screen-relative character-cell coordinates is enclosed by a given window, returning TRUE if it is and FALSE otherwise. It is useful for determining what subset of the screen windows enclose the location of a mouse event.

If the parameter is a pad, wenclose uses the most recent screen coordinates used for this pad in prefresh(3X) or pnoutrefresh(3X).

wmouse_trafo

The wmouse_trafo function transforms a given pair of coordinates from stdscr-relative coordinates to coordinates relative to the given window or vice versa. The resulting stdscr-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 ripoffline(3X) and slk_init(3X) calls, for example).

•: If the parameter to_screen is TRUE, the pointers pY, pX must reference the coordinates of a location inside the window win. They are converted to stdscr-relative coordinates and returned through the pointers. If the conversion was successful, the function returns TRUE.

: If one of the parameters was NULL or the location is not inside the window, FALSE is returned.

•: If to_screen is FALSE, the pointers pY, pX must reference stdscr-relative coordinates. They are converted to window-relative coordinates if the window win encloses this point. In this case the function returns TRUE.

: If one of the parameters is NULL or the point is not inside the window, FALSE is returned.

The referenced coordinates are only replaced by the converted coordinates if the transformation was successful.

mouse_trafo

The mouse_trafo function performs the same translation as wmouse_trafo, using stdscr for win.

mouseinterval

The mouseinterval 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 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 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.

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 corresponding screen is initialized, e.g., in initscr(3X) or setupterm(3X).

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 if no more events remain in the queue.

ungetmouse returns an error 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 will not be visible to ncurses (and the mousemask function will always return 0).

If the terminfo entry contains a XM string, this is used in the xterm mouse driver to control the way the terminal is initialized for mouse operation. The default, if XM is not found, corresponds to private mode 1000 of xterm:

\E[?1000%?%p1%{1}%=%th%el%;

The mouse driver also recognizes a newer xterm private mode 1006, e.g.,

\E[?1006;1000%?%p1%{1}%=%th%el%;

The z 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.

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 button-releases.

EXTENSIONS

These functions were designed for ncurses(3X), 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 a different type.)

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 versions are available when ncurses is configured; see section “ALTERNATE CONFIGURATIONS” of ncurses(3X). The following values may be specified.

1: has definitions for reserved events. The mask uses 28 bits.
2: adds definitions for button 5, removes the definitions for reserved events. The mask uses 29 bits.

SVr4 curses had support for the mouse in a variant of xterm(1). It is mentioned in a few places, with little supporting documentation.

•: Its “libcurses” manual page lists functions for this feature prototyped 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 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 req_mouse_pos 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 compatibility with the escape sequences.

BUGS

Mouse events from xterm are not ignored in cooked mode if they have been enabled by mousemask. Instead, the xterm mouse report sequence appears in the string read.

An ncurses window must enable keypad(3X) to correctly receive mouse event reports from xterm since they are encoded like function keys. Set the terminal's terminfo capability kmous to “\E[M” (the beginning of the response from xterm for mouse clicks). Other values of kmous 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 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. The kmous capability is checked first, allowing use of newer xterm mouse protocols, such as its private mode 1006.