| 摘要 |
<p>PURPOSE:To reduce the quantity of data to be transferred and shorten time for transfer by providing a change extent extracting section that executes necessary minimum transfer at the time of reflecting partial change of a square image pattern of a first memory section to a second memory section. CONSTITUTION:At the time of reflecting partials change of a square image pattern held in a bit map memory section 1 as the first memory section to a screen memory section 3 as the second memory section, necessary minimum transfer is executed by a change extent extracting section 8. That is, when change occurred, the position of the part of the bit map memory section 1 is detected, and converted to coordinate value on the memory section 3 according to positional information on the screen memory 3, and an area of changed extent is outputted to an area discriminating section 4. The discriminating section 4 divides the extent of changed extent area value into mutually overlapped small square areas using disposition information in a controlling section 2 and makes decision, and transfers an image pattern corresponding to necessary small square area from the memory section 1 to the memory section 3. Thus, the quantity of the data to be transferred is reduced, and time for transfer can be shortened.</p> |
