DOKK / manpages / debian 10 / ncurses-doc / mouse_trafo.3ncurses.en
mouse(3NCURSES) mouse(3NCURSES)

has_mouse, getmouse, ungetmouse, mousemask, wenclose, mouse_trafo, wmouse_trafo, mouseinterval - mouse interface through curses

#include <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);
int getmouse(MEVENT *event);
int ungetmouse(MEVENT *event);
mmask_t mousemask(mmask_t newmask, mmask_t *oldmask);
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);

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

To make mouse events visible, use the mousemask function. This will set the mouse events to be reported. By default, no mouse events are reported. The function will return a mask to indicate which of the specified mouse events can be reported; on complete failure it returns 0. If oldmask is non-NULL, this function fills the indicated location with the previous value of the given window's mouse event mask.

As a side effect, setting a zero mousemask may turn off the mouse pointer; setting a nonzero mask may turn it on. Whether this happens is device-dependent.

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

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.

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.

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.

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 window-relative coordinates due to the mechanism to reserve lines on top or bottom of the screen for other purposes (see the ripoffline 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 window-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 window-relative coordinates. They are converted to stdscr-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.

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

The mouseinterval function sets the maximum time (in thousands of a second) that can elapse between press and release events for them to be recognized as a click. Use mouseinterval(0) to disable click resolution. This function returns the previous interval value. Use mouseinterval(-1) to obtain the interval without altering it. The default is one sixth of a second.

The has_mouse function returns TRUE if the mouse driver has been successfully initialized.

Note that mouse events will be ignored when input is in cooked mode, and will 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.

getmouse and ungetmouse return the integer ERR upon failure or OK upon successful completion:

getmouse
returns an error.
  • If no mouse driver was initialized, or if the mask parameter is zero,
  • It also returns an error if no more events remain in the queue.
ungetmouse
returns an error if the FIFO 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).

wenclose and wmouse_trafo are boolean functions returning TRUE or FALSE depending on their test result.

These calls were designed for ncurses(3NCURSES), and are not found in SVr4 curses, 4.4BSD curses, or any other previous version of curses.

SVr4 curses had support for the mouse in a variant of xterm. It is mentioned in a few places, but with no supporting documentation:

  • the “libcurses” manual page lists functions for this feature which are 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);

  • the “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 which had been modified to work with 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.

The feature macro NCURSES_MOUSE_VERSION is provided so the preprocessor can be used to test whether these features are present. If the interface is changed, the value of NCURSES_MOUSE_VERSION will be incremented. These values for NCURSES_MOUSE_VERSION may be specified when configuring ncurses:

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.

The order of the MEVENT structure members is not guaranteed. Additional fields may be added to the structure in the future.

Under ncurses(3NCURSES), 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(3NCURSES) (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 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.

Mouse events under xterm will not in fact be ignored during cooked mode, if they have been enabled by mousemask. Instead, the xterm mouse report sequence will appear in the string read.

Mouse events under xterm will not be detected correctly in a window with its keypad bit off, since they are interpreted as a variety of function key. Your terminfo description should have kmous set to "\E[M" (the beginning of the response from xterm for mouse clicks). Other values for kmous are permitted, but under the same assumption, i.e., it is the beginning of the response.

Because there are no standard terminal responses that would serve to identify terminals which support the xterm mouse protocol, ncurses assumes that if your $TERM environment variable contains "xterm", or kmous is defined in the terminal description, then the terminal may send mouse events.

ncurses(3NCURSES), kernel(3NCURSES), slk(3NCURSES), curses_variables(3NCURSES).