| 摘要 |
PURPOSE:To reduce the storage capacity of a CPU and at the same time to improve image processing efficiency by providing an image drawing arithmetic control means and producing a window pattern through a window memory having a size corresponding to a frame memory. CONSTITUTION:A CRT controller 6 contains an image drawing processor 11 having an image drawing arithmetic control means and controls the transfer of data with a window memory 5 based on the command data sent from a host CPU 7. Then image arithmetic is carried out with an access of the prescribed image data on a frame memory 2. In this case, a window pattern is produced at the memory 5 to designate the validity or invalidity of the arithmetic carried out by an image processing arithmetic processor 1 in a size corresponding to the memory 2. Thus the storage capacity of a main CPU can be reduced and at the same time the arithmetic validity or invalidity can be designated for each picture element of the memory 2. This improves the image processing efficiency. |
