| 摘要 |
PURPOSE:To increase the drawing speed of a circular arc by executing an real coordinate calculation processing on a bit map memory at each point of the circular arc, successively and gradually along one stroke writing. CONSTITUTION:A CPU21, memory 22, bit map memory 23, register memory group 26, and a bit map memory addressing mechanism 30 are connected in common to a bus line 27. A logical device 24 in the bit map memory addressing mechanism 30 updates and outputs an address of bit map memory 23 successively and gradually with respect to updating of an address by a dot unit corresponding to the horizontal direction on a display, and a logical device 25 updates an address of the bit map memory 23 with respect to the vertical direction. The register memory 26 is constituted of registers 261-266, and a logical coordinate value in the horizontal/vertical directions; a discriminating function value, quadrant information, aspect ratio of a physical picture element, etc. are set to these registers 261-266. |
