Subversion Repositories planix.SVN

.TH MOUSE 2

.SH NAME

initmouse, readmouse, closemouse, moveto, getrect, drawgetrect, menuhit, setcursor \- mouse control

.SH SYNOPSIS

.nf

.B

#include <u.h>

.B

#include <libc.h>

.B

#include <draw.h>

.B

#include <thread.h>

.B

#include <mouse.h>

.B

#include <cursor.h>

.PP

.B

Mousectl	*initmouse(char *file, Image *i)

.PP

.B

int		readmouse(Mousectl *mc)

.PP

.B

int		atomouse();

.PP

.B

void		closemouse(Mousectl *mc)

.PP

.B

void		moveto(Mousectl *mc, Point pt)

.PP

.B

void		setcursor(Mousectl *mc, Cursor *c)

.PP

.B

Rectangle	getrect(int but, Mousectl *mc)

.PP

.B

void		drawgetrect(Rectangle r, int up)

.PP

.B

int		menuhit(int but, Mousectl *mc, Menu *menu, Screen *scr)

.fi

.SH DESCRIPTION

These functions access and control a mouse in a multi-threaded environment.

They use the message-passing

.B Channel

interface in the threads library

(see

.IR thread (2));

programs that wish a more event-driven, single-threaded approach should use

.IR event (2).

.PP

The state of the mouse is recorded in a structure,

.BR Mouse ,

defined in

.BR <mouse.h> :

.IP

.EX

.ta 6n +\w'Rectangle 'u +\w'buttons;   'u

typedef struct Mouse Mouse;

struct Mouse

{

	int	buttons;	/* bit array: LMR=124 */

	Point	xy;

	ulong	msec;

};

.EE

.PP

The

.B Point

.B xy

records the position of the cursor,

.B buttons

the state of the buttons (three bits representing, from bit 0 up, the buttons from left to right,

and

.BR msec ,

a millisecond time stamp.

.PP

The routine

.B initmouse

returns a structure through which one may access the mouse:

.IP

.EX

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 */

};

.EE

.PP

The arguments to

.I initmouse

are a

.I file

naming the device file connected to the mouse and an

.I Image

(see

.IR draw (2))

on which the mouse will be visible.

Typically the file is

nil,

which requests the default

.BR /dev/mouse ;

and the image is the window in which the program is running, held in the variable

.B screen

after a call to

.IR initdraw .

.PP

Once the

.B Mousectl

is set up,

mouse motion will be reported by messages of type

.B Mouse

sent on the

.B Channel

.BR Mousectl.c .

Typically, a message will be sent every time a read of

.B /dev/mouse

succeeds, which is every time the state of the mouse changes.

.PP

When the window is resized, a message is sent on

.BR Mousectl.resizec .

The actual value sent may be discarded; the receipt of the message

tells the program that it should call

.B getwindow

(see

.IR graphics (2))

to reconnect to the window.

.PP

.I Readmouse

updates the

.B Mouse

structure held in the

.BR Mousectl ,

blocking if the state has not changed since the last

.I readmouse

or message sent on the channel.

It calls

.B flushimage

(see

.IR graphics (2))

before blocking, so any buffered graphics requests are displayed.

.PP

.I Closemouse

closes the file descriptors associated with the mouse, kills the slave processes,

and frees the

.B Mousectl

structure.

.PP

.I Moveto

moves the mouse cursor on the display to the position specified by

.IR pt .

.PP

.I Setcursor

sets the image of the cursor to that specified by

.IR c .

If

.I c

is nil, the cursor is set to the default.

The format of the cursor data is spelled out in

.B <cursor.h>

and described in

.IR graphics (2).

.PP

.I Getrect

returns the dimensions of a rectangle swept by the user, using the mouse,

in the manner

.IR rio (1)

or

.IR sam (1)

uses to create a new window.

The

.I 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.

.PP

.I Getrect

uses successive calls to

.I drawgetrect

to maintain the red rectangle showing the sweep-in-progress.

The rectangle to be drawn is specified by

.I rc

and the

.I up

parameter says whether to draw (1) or erase (0) the rectangle.

.PP

.I Menuhit

provides a simple menu mechanism.

It uses a

.B Menu

structure defined in

.BR <mouse.h> :

.IP

.EX

typedef struct Menu Menu;

struct Menu

{

	char	**item;

	char	*(*gen)(int);

	int	lasthit;

};

.EE

.PP

.IR Menuhit

behaves the same as its namesake

.I emenuhit

described in

.IR event (2),

with two exceptions.

First, it uses a

.B Mousectl

to access the mouse rather than using the event interface;

and second,

it creates the menu as a true window on the

.B Screen

.I scr

(see

.IR window (2)),

permitting the menu to be displayed in parallel with other activities on the display.

If

.I scr

is null,

.I menuhit

behaves like

.IR emenuhit ,

creating backing store for the menu, writing the menu directly on the display, and

restoring the display when the menu is removed.

.PP

.SH SOURCE

.B /sys/src/libdraw

.SH SEE ALSO

.IR graphics (2),

.IR draw (2),

.IR event (2),

.IR keyboard (2),

.IR thread (2).