MOUSE(3) MOUSE(3)
NAME
initmouse, readmouse, closemouse, moveto, cursorswitch,
getrect, drawgetrect, menuhit, setcursor - mouse control
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <thread.h>
#include <mouse.h>
#include <cursor.h>
Mousectl *initmouse(char *file, Image *i)
int readmouse(Mousectl *mc)
int atomouse();
void closemouse(Mousectl *mc)
void moveto(Mousectl *mc, Point pt)
void setcursor(Mousectl *mc, Cursor *c)
Rectangle getrect(int but, Mousectl *mc)
void drawgetrect(Rectangle r, int up)
int menuhit(int but, Mousectl *mc, Menu *menu, Screen *scr)
DESCRIPTION
These functions access and control a mouse in a multi-
threaded environment. They use the message-passing Channel
interface in the threads library (see thread(3)); programs
that wish a more event-driven, single-threaded approach
should use event(3).
The state of the mouse is recorded in a structure, Mouse,
defined in <mouse.h>:
typedef struct Mouse Mouse;
struct Mouse
{
int buttons; /* bit array: LMR=124 */
Point xy;
ulong msec;
};
The Point xy records the position of the cursor, buttons the
state of the buttons (three bits representing, from bit 0
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MOUSE(3) MOUSE(3)
up, the buttons from left to right, 0 if the button is
released, 1 if it is pressed), and msec, a millisecond time
stamp.
The routine initmouse returns a structure through which one
may access the mouse:
typedef struct Mousectl Mousectl;
struct Mousectl
{
Mouse;
Channel *c; /* chan(Mouse)[16] */
Channel *resizec; /* chan(int)[2] */
char *file;
int mfd; /* to mouse file */
int cfd; /* to cursor file */
int pid; /* of slave proc */
Image* image; /* of associated window/display */
};
The arguments to initmouse are a file naming the device file
connected to the mouse and an Image (see draw(3)) on which
the mouse will be visible. Typically the file is nil, which
requests the default /dev/mouse; and the image is the window
in which the program is running, held in the variable screen
after a call to initdraw.
Once the Mousectl is set up, mouse motion will be reported
by messages of type Mouse sent on the Channel Mousectl.c.
Typically, a message will be sent every time a read of
/dev/mouse succeeds, which is every time the state of the
mouse changes.
When the window is resized, a message is sent on
Mousectl.resizec. The actual value sent may be discarded;
the receipt of the message tells the program that it should
call getwindow (see graphics(3)) to reconnect to the window.
Readmouse updates the Mouse structure held in the Mousectl,
blocking if the state has not changed since the last
readmouse or message sent on the channel. It calls
flushimage (see graphics(3)) before blocking, so any buf-
fered graphics requests are displayed.
Closemouse closes the file descriptors associated with the
mouse, kills the slave processes, and frees the Mousectl
structure.
Moveto moves the mouse cursor on the display to the position
specified by pt.
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MOUSE(3) MOUSE(3)
Setcursor sets the image of the cursor to that specified by
c. If c is nil, the cursor is set to the default. The for-
mat of the cursor data is spelled out in <cursor.h> and
described in graphics(3).
Getrect returns the dimensions of a rectangle swept by the
user, using the mouse, in the manner rio(1) or sam(1) uses
to create a new window. The but argument specifies which
button the user must press to sweep the window; any other
button press cancels the action. The returned rectangle is
all zeros if the user cancels.
Getrect uses successive calls to drawgetrect to maintain the
red rectangle showing the sweep-in-progress. The rectangle
to be drawn is specified by rc and the up parameter says
whether to draw (1) or erase (0) the rectangle.
Menuhit provides a simple menu mechanism. It uses a Menu
structure defined in <mouse.h>:
typedef struct Menu Menu;
struct Menu
{
char **item;
char *(*gen)(int);
int lasthit;
};
Menuhit behaves the same as its namesake emenuhit described
in event(3), with two exceptions. First, it uses a Mousectl
to access the mouse rather than using the event interface;
and second, it creates the menu as a true window on the
Screen scr (see window(3)), permitting the menu to be dis-
played in parallel with other activities on the display. If
scr is null, menuhit behaves like emenuhit, creating backing
store for the menu, writing the menu directly on the dis-
play, and restoring the display when the menu is removed.
SOURCE
/usr/local/plan9/src/libdraw
SEE ALSO
graphics(3), draw(3), event(3), keyboard(3), thread(3).
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