| 摘要 |
PROBLEM TO BE SOLVED: To efficiently access the reference of a background or a principal picture, to reducer overhead by switching read/write by dedicating a plotting port only for writing, to accelerate its operational speed and to improve the picture quality of a transparent image, etc. SOLUTION: This device is provided with a frame buffer 120 provided with the plotting port 121 and a displaying port 122 and a plotting circuit 110. In a blanking interval of a video signal read out from the frame buffer 120, a read-out address for reading out the reference data is generated by the plotting circuit 110. The background reference data read out from the plotting area 123 of the frame buffer, the principal picture reference data, etc., read out from a principal picture area 125 by this read-out address are outputted from the displaying port 122 in the blanking interval to be sent to the plotting circuit 110, and these are used for operation at the time of translucent plotting in the plotting circuit 110. Thus, the displaying port in the blanking interval is used effectively.
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