| 摘要 |
PROBLEM TO BE SOLVED: To provide a quadrangle plotting method and apparatus by which plotting omission due to the error of a digital differential analyzer(DDA) does not occur in the case of plotting a quadrangle surface by plotting a plurality of line segments. SOLUTION: Each vertex coordinate of a quadrangle as a subject of plotting is inputted, the starting point and the end point of a line segment are calculated to plot the line segment from one point of a side to one point of the opposite side between adjacent two vertexes, and then the DDA gradient of the line segment is calculated. The maximum error of the end point coordinate of the line segment is calculated on the basis of the error of the DDA gradient and the length of the line segment, and the line segment is plotted as a parallelogram having a width W equivalent to two times of the maximum error. |
