Axis constant: Y axis of a motion event.

• For a touch screen, reports the absolute Y screen position of the center of the touch contact area. The units are display pixels.
• For a touch pad, reports the absolute Y surface position of the center of the touch contact area. The units are device-dependent; use InputDevice.GetMotionRange(Axis) to query the effective range of values.
• For a mouse, reports the absolute Y screen position of the mouse pointer. The units are display pixels.
• For a trackball, reports the relative vertical displacement of the trackball. The value is normalized to a range from -1.0 (up) to 1.0 (down).
• For a joystick, reports the absolute Y position of the joystick. The value is normalized to a range from -1.0 (up or far) to 1.0 (down or near).