| 摘要 |
A prefetch size for drawing calculating unit 6 determines a prefetch size for drawing on the basis of a scroll speed and a scroll direction. A prefetch area for drawing calculating unit 7 determines a prefetch area for drawing from the scroll speed, the scroll direction, and the prefetch size for drawing. A back-side drawing memory 11 stores map data about the prefetch area for drawing, and is interchanged with a front-side drawing memory 12. A rectangle extracting unit 14 extracts a rectangular area for display from the front-side drawing memory 12 with which the back-side drawing memory is interchanged, and this rectangular area for display is displayed by a display unit 15. |
