| 摘要 |
PURPOSE:To eliminate an unnatural sense by switching a video signal read out of an external screen information holding means and an internal screen signal in accordance with a value read out of a screen display information holding means, and displaying an external screen, as well as one of windows. CONSTITUTION:In an external screen writing means 2, an address of an information holding means 1 is derived from values shown by X position and Y position counters 11, 12, and in accordance with an external dot clock 61, an external screen signal 50 is written in the means 1. Its information is read out by a reading-out means 3. On the other hand, a synchronizing external screen signal 56 from the means 1 passes through a D/A converter 7 and inputted to a switching means 4. On the other hand, a standard range instructing signal 58 read out by the means 3 is outputted to the means 4. Whenever a window is varied, a screen display signal 54, and a screen display instructing information write instructing signal are inputted to a holding means 5, and a writing means 6, respectively, and from the means 5, a write instruction is outputted to the means 5. The means 4 receives an inside surface screen signal 52, switches an external screen signal 57 and outputs the signal 52 as an output screen signal 60 to a display device 8. |
