| 摘要 |
PROBLEM TO BE SOLVED: To extend a time for writing image data by shortening a time for reading out image data from a frame buffer composed of DRAM. SOLUTION: An image processor 71 stores a map and a GUI image in a frame buffer composed of DRAM and also divides the frame buffer 74 storing the GUI image 101 into many blocks consisting of m by n picture elements, and stores the data in transparent/opaque block storage part 82, which indicates whether or not an opaque color part of the GUI image exists in each block. In the case of reading out, the image processor 71 refers to the stored data and determines whether the opaque color part of the GUT image exists in the block to which the image to be read belongs, and if it does not exists, the processor reads out only the map image, but if it exists, the processor reads out each map image and GUI image from the map frame buffer and GUI frame buffer respectively and displays the map and the GUI image. |
