| 摘要 |
PROBLEM TO BE SOLVED: To obtain a sharp image by delaying image data to be overlaid by an arbitrary time after detecting a transparent color to eliminate a position deviation at the time of detecting the transparent color. SOLUTION: A position detecting circuit 1 detects whether a coordinate position performing a display at present is a position where the image to be overlaid is to be ovelaid or not. A transparent color detecting circuit 2 detects whether the image data being displayed at present is of a designated transparent color or not. An AND circuit 3 ANDs detection signals of the position detecting circuit 1 and the transparent color detecting circuit 2 and when they coincide, the AND circuit 3 changes over the image data path of a changeover circuit 6 from an overlaying image data to the image to be overlaid. Moreover, a register circuit 5 sets how many dots of the image to be overlaid are to be delayed to transmit the setting information to a delay circuit 4, which, then, transmits the image data to be overlaid to the changeover circuit 6 by shifting them in a dot clock unit. |
