假设在实际轮廓起始点处沿x方向走一小段(一个脉冲当量),发现终点在实际轮廓的下方,则下一条线段沿y方向走一小段,此时如果线段终点还在实际轮廓下方,则继续沿y方向走一小段,直到在实际轮廓上方以后,再向x方向走一小段,依次循环类推-The hypothesis in actual contour starting point along the x direction in a short (a pulse equivalent), found that the finish in the actual contour below, is under a line along the y direction for a short, if this time the actual contour line in below, then continue down y direction for a short, until in the actual contour above, then to after x direction for a short