| 摘要 |
<p>PURPOSE:To execute a control for changing the priority of a display screen at a high speed, by suppressing the data transfer amount extending from a window memory to a frame memory, to the necessary minimum, in case of changing the display priority of a multi-window display screen. CONSTITUTION:An X direction register 1 shows a window boundary which exists in a coordinate in the X direction of a display screen 3. Also, a Y direction register 2 shows a window boundary which exists in the Y direction of the screen 3. When a change of combination of windows becomes necessary, a priority order of a window number of a priority managing register is rewritten by a window change means 4, in accordance with window boundary data of the register 1 and the register 2. According to this constitution, a control for changing the priority of the display screen can be executed at a high speed by changing the data of only a superposed part of the displayed window.</p> |
