source files: xbtp.[ch]
(XBTP-READ-STATE [ :block-until-input-arrives nil ] )
This fn is designed to be compatible with the class-camera :read-mouse-state message, but reading from a data tablet instead of the mouse. It won't notice keyboard or redraw events, of course.
Sets XG.3D-MOUSE-ROW and XG.3D-MOUSE-COL to position of bitpad puck, and XG.3D-MOUSE-STATE to :UPCLICK, :DOWNCLICK, :DRAG, :SELECT or NIL as appropriate, depending on state of puck buttons, following the camera :RUN-WIDGETS message conventions.
Also sets XG.3D-MOUSE-PRESSURE to a value in the range 0-1024. For most drivers, this value will just be 0 or 1024 according as to whether a or not a button is pressed, and isn't very useful; for the Wacom using the pressure-sensitive stylus, this will be one of 65 values equally spaced from 0 to 1024, depending on how hard the user is pressing on the stylus.
Returns value XG.3D-MOUSE-STATE was set to. If the data tablet puck has moved, xbtp-puck-moved is set T, else NIL.