摘要 |
A drawing instruction processor refers to a bit map line table that shows whether the bit arrays in the row unit are the same in the order of concentrations. The drawing instruction processor decides whether dither patterns to be used for the adjacent specified drawing ranges are the same, by referring to the BLT, and links the drawing ranges to which the same pattern can be applied. Based on this, the drawing processor carries out a batch writing using a dither pattern prepared in advance into the specified range in the page memory. The dither pattern to be used for the drawing is prepared by linking a plurality of the same basic patterns to have a length corresponding to the length of the word length. As a result of such an arrangement, it is possible to achieve a high-speed processing.
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