GRAPHIC DISPLAY DEVICE AND EXTERNAL GRAPHIC CONTROLLER

摘要

PURPOSE:To superpose an external graphic window on a normal graphic window with no use of a special event. CONSTITUTION:A window monitor program 100 is provided to a graphic work station controller 14. Then the program 100 supplies the information on the window display area designated by a pointing device 10 via a video synthesizing circuit control line 24 to a video synthesizing circuit 20. The circuit 20 generates a mask pattern based on the received information and then synthesizes the video signals A and B based on the mask pattern to output the synthetic signal to e CRT 18. The program 100 controls the relation between the normal and external windows and therefore the generation of a special event is not required. Furthermore the working performance of a user is satisfactory.