To increase a process speed by carrying out straight line drawing only for the rest of an ellipse by writing hue data in memory locations of the pixels in a quadrangle included in the ellipse and writing hue data in the memory locations of the rest of the ellipse.

The quadrangle included in the ellipse is selected first and after the hue data are written in the memory locations corresponding to the pixels in the quadrangle, the hue data are written in the memory locations corresponding to the rest of the ellipse except the quadrangle part. By this elliptic filling method, the vertexes of the quadrangle inscribed in the ellipse are calculated (S300) and the quadrangle consisting of those vertexes is filled fast by memory block copying (S302). Then points on the circumference in the memory locations corresponding to the pixels of a horizontal line and memory locations corresponding to the pixels of a vertical line in the rest of the ellipse except the quadrangle are calculated (S304) and while the respective points are connected by the horizontal line and vertical line, the hue data are written in the memory locations corresponding to the respective pixels to fill the inside of the ellipse (S306).