They are not available from programs compiled by camlc and run under the MPW shell. The graphics primitive are available from the Windows application that runs the toplevel system. They are not available from programs compiled by camlc and run in a DOS command window. Drawing takes place in a separate window. The screen coordinates are interpreted as shown in the figure below.
Drawing is clipped to the screen.
The two components are separated by a space. Either can be omitted, or both. Show the graphics window or switch the screen to graphic mode. The graphics window is cleared. The string argument is used to pass optional information on the desired graphics mode, the graphics window size, and so on.