| 摘要 |
<p>It is possible to reduce the number of useless accesses to a graphics memory device. When reading in image data from frame buffers (21-1), (21-2), (21-3) or windows (22-1), (22-2), (22-3) by an image data read-in unit (11), a mask area inside/outside judgment unit (13) references mask information stored in a mask information storage unit (12) and judges whether the image data being scanned is contained in the memory access areas (23a), (23b), (23c), (23d). When the image data being scanned is contained in the memory access areas (23a), (23b), (23c), (23d), a superimposing processing unit (14) performs superimposing processing in accordance with the transparency attribute assigned to the memory access mask areas (23a), (23b), (23c), (23d) regardless of the transparency attribute of the frame buffers (21-1), (21-2), (21-3) or the windows (22-1), (22-2), (22-3).</p> |
