APPARATUS, SYSTEM AND METHOD FOR CONTROLLING OVERLAY PLANE IN GRAPHIC DISPLAY SYSTEM

摘要

PURPOSE: To selectively control overlay characteristics which are common to many windows selectively by graphic processing environment windows while performing operation in the context of conventional RAMDAC overlay control architecture. CONSTITUTION: Window specific overlay control is performed by combining window, masking, and overlay data as address with a mapping memory. The bit contents of the mapping memory are controlled directly by a general processor and the relation between the combined input and mapping memory output as a state supplied to the overlay output of RAMDAC is selectively prescribed. Therefore, a common overlay is corrected selectively by the windows.