POINTER 3
NAME
pointer - mouse and stylus interface
SYNOPSIS
"bind -a #m /dev"
/dev/cursor
/dev/pointer
DESCRIPTION
The
pointer device is the interface to input from a mouse, stylus, or some other device
for pointing at positions on a display.
On some platforms, the pointer is associated with a cursor
on the display, that is displayed at the current pointer position.
There often are buttons associated with the pointer, whether on
the pointing device or elsewhere.
For instance, some of the buttons on a PDA might be associated
with the stylus not a keypad, to allow modification of stylus actions
when there are are no buttons on the stylus itself.
In the hosted environment of
emu (1), the pointer is associated with the host system's own pointing device.
Reading the
pointer file returns the current pointer position and the state of any buttons associated with the pointer.
The read blocks until the state has changed since the last read.
Each read returns a 49 byte record:
m "x y buttons msec"
Each record has the letter
m immedlately followed by four 11-character decimal numbers, each number ended by a blank.
X and
y give the coordinates of the pointer in display coordinates;
the value
buttons has bit
"(1<<" b ) set when button
b is down; and
msec is a time stamp in milliseconds.
Writing a record of the above form to
pointer moves the displayed cursor to the given
x and
y position;
buttons and
msec are ignored.
Writing an
image (6) file to the
cursor file sets the image of the cursor on the display.
Reading
cursor returns the current cursor image, again in
image (6) format.
SOURCE
/emu/port/devpointer.c
/os/port/devpointer.c
SEE ALSO
wm (1), draw-intro (2), image (6)