| 摘要 |
<p>PURPOSE:To switch a window at high speed by calculating a visible area (effective picture area) only on the extracted window when a window priority switching (change) is requested. CONSTITUTION:A memory 20 has a program part 14, a window register part 16 to which window information is set for window unit, a display priority register part 18 and a video register part 20 of a two-dimentional array for storing an effective picture area occupied on the physical picture of a window area. When the change of the display priority of an arbitrary window is instructed, whether the present display priority of the window to be changed is higher or lower than an object display priority is decided, based on the decision result and the present display priority of the window to be changed and the object display priority, a display priority memory means 18 for storing the window display priority is referred, thereby, a priority changed window in which the display priority is changed according to the change in the display priority of the window to be changed is detected. The visible area is obtained only on the priority changed window and the window to be changed.</p> |
