包括计算机实习的常见基本算法： 有breshham、中点、和DDA画线法 还有常见的画圆、椭圆和矩形算法 对于了解计算机底层的画图机制有很强的参考作用-Including computer basic algorithm common practice: Have breshham, midpoint, and the DDA painting method also common drawcircle, oval and rectangular computer algorithm