absolute vs. relative movement An absolute-movement input device (e.g., stylus, finger on touch screen) provides a consistent mapping between a point in the input space (location/state of the input device) and a point in the output space (position of pointer on screen). A relative-movement input device (e.g., mouse, joystick) maps displacement in the input space to displacement in the output state. It therefore controls the relative position of the cursor compared to its initial position.
absolute vs. relative movement An absolute-movement input device (e.g., stylus, finger on touch screen) provides a consistent mapping between a point in the input space (location/state of the input device) and a point in the output space (position of pointer on screen). A relative-movement input device (e.g., mouse, joystick) maps displacement in the input space to displacement in the output state. It therefore controls the relative position of the cursor compared to its initial position.