计算机图形学大作业 完成DDA，bresenham算法画直线，绘制圆和椭圆，区域填充，裁剪等功能。-Computer graphics major operation to complete DDA, bresenham algorithm drawing a straight line, circle and ellipse drawing, area filling, cutting and other functions.

lineto function draws a line current position(CP) to the point(x,y), you can get current position using getx and gety function.-lineto function draws a line current position(CP) to the point(x,y), you can get current position using getx and gety fun