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pointer - mouse and stylus interface


bind -a #m /dev



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:

mx 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.




wm(1), draw-intro(2), image(6)

POINTER(3 ) Rev:  Thu Feb 15 14:43:36 GMT 2007