The GrafPort defined a coordinate system. In QuickDraw, this had a resolution of 16 bits, giving 65,536 unique vertical and horizontal locations. These are numbered from -32,767 on the extreme left (or top), to +32,767 on the extreme right (or bottom). A window was usually set up so that the top, left corner of its content area was located at 0,0 in the associated GrafPort. A window's content area did not include the window's frame, drop shadow or title bar (if any).