| 摘要 |
PURPOSE:To make a superposed graphic easily visible, and to increase a display speed by writing a graphic which has been generated by a superposed graphic generating part, as it is, to an image memory, and providing a saving means for saving and resetting the graphic corresponding to a superposed part. CONSTITUTION:A rubber band picture drawing device 21 generates a superposed display graphic, based on a point given by a mouse. At the time of writing it in a bit map memory 1A, that which corresponds to a graphic which has been generated in the picture drawing device 21, in the display contents to be stored is saved in a saving memory 32. A correcting part 22 derives a value of a picture element of the periphery of a superposed part of a rubber band graphic which has been given from a background drawing stored in the memory 1A, and corrects it to an easily visible pattern. When the picture drawing device 21 has generated the next graphic, a reading/writing circuit 31 writes the contents which have been saved in the memory 32, in the memory 1A, and reset said graphic to its old background graphic. In this way, the superposed graphic becomes easily visible, and also, a display speed can be increased. |
