| 摘要 |
<p>A graphic controller having a function of painting an area designated by four points is disclosed. The respective X-coordinate values on a first line connecting the first and second points and a second line connecting the third and fourth points are calculated and produced. Each one of the X-coordinate values on the first line is compared with the associated one of the X-coordinate value on the second line to detect an intersection point of the first and second lines. In response to the comparison output, one of the X-coordinate values on the first and second lines is employed as a drawing start coordinate information, or a drawing direction is inverted. The area designated by the four points is thereby painted at a high speed.</p> |
