问 在LCD中画横线和竖线很容易，但画斜线就有点麻烦。
看了各类画斜线函数都SO 长，看的很费劲，我比较懒
没去看，自己写了个用对递归－添中点的方式，很容易
看懂，只是画的线不是很平滑。放在这儿供大家讨论。
void Line(int x0,int y0,int x1,int y1,int color)
{
  int xCenter,yCenter;
  int dx,dy;
  static int oneTime=1;/*两端点独立画，且只画一次*/
  dx=(x1-x0)/2;
  dy=(y1-y0)/2;
  xCenter=x0+dx;
  yCenter=y0+dy;
  if(oneTime==1)/*两端点独立画，且只画一次*/
  {
    putpixel(x0,y0,color);
    putpixel(x1,y1,color);
    oneTime=0;
  }
  if(dx==0&&dy==0)/*如果已经填满了，退出*/
     return;
  else if(dx!=0|dy!=0)
  {
    putpixel(xCenter,yCenter,color);/*画中点*/
    Line(x0,y0,xCenter,yCenter,color);/*上半线条继续画*/
    Line(xCenter,yCenter,x1,y1,color);/*下半线条继续画*/
  }
}
答 1: ...画线关键是要速度快，避免乘法，开销尽量小。你这样只能自娱一下。还是研究一下Bresenham算法吧，很简单的。 答 2: Bresenham画斜线算法void Bre_Line(int x1,int y1,int x2,int y2,int color)
{
    int dx,dy,e;
    dx=x2-x1;
    dy=y2-y1;

    if(dx>=0)
    {
        if(dy >= 0) // dy>=0
        {
            if(dx>=dy) // 1/8 octant
            {
                e=dy-dx/2;
                while(x1<=x2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){y1+=1;e-=dx;}
                    x1+=1;
                    e+=dy;
                }
            }
            else        // 2/8 octant
            {
                e=dx-dy/2;
                while(y1<=y2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){x1+=1;e-=dy;}
                    y1+=1;
                    e+=dx;
                }
            }
        }
        else           // dy<0
        {
            dy=-dy;   // dy=abs(dy)

            if(dx>=dy) // 8/8 octant
            {
                e=dy-dx/2;
                while(x1<=x2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){y1-=1;e-=dx;}
                    x1+=1;
                    e+=dy;
                }
            }
            else        // 7/8 octant
            {
                e=dx-dy/2;
                while(y1>=y2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){x1+=1;e-=dy;}
                    y1-=1;
                    e+=dx;
                }
            }
        }
    }
    else //dx<0
    {
        dx=-dx;        //dx=abs(dx)
        if(dy >= 0) // dy>=0
        {
            if(dx>=dy) // 4/8 octant
            {
                e=dy-dx/2;
                while(x1>=x2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){y1+=1;e-=dx;}
                    x1-=1;
                    e+=dy;
                }
            }
            else        // 3/8 octant
            {
                e=dx-dy/2;
                while(y1<=y2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){x1-=1;e-=dy;}
                    y1+=1;
                    e+=dx;
                }
            }
        }
        else           // dy<0
        {
            dy=-dy;   // dy=abs(dy)

            if(dx>=dy) // 5/8 octant
            {
                e=dy-dx/2;
                while(x1>=x2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){y1-=1;e-=dx;}
                    x1-=1;
                    e+=dy;
                }
            }
            else        // 6/8 octant
            {
                e=dx-dy/2;
                while(y1>=y2)
                {
                    putpixel(x1,y1,color);
                    if(e>0){x1-=1;e-=dy;}
                    y1-=1;
                    e+=dx;
                }
            }
        }
    }
}
答 3: 对比Bresenham算法和中点算法我们可以看到，Bresenham算法和中点算法一样都是乘2或者除2，这里都是除2，而乘2或者除2在计算机中只是左移1位（乘2）或右移1位（除2），速度相当快，因此这两个算法的速度都非常快，而且中点法略快于Bresenham算法（因为程序简单），但光滑度比不上Bresenham算法。如果两点间距离能被2连续整除的次数很多，则中点法画出来的直线也相当光滑大家可以试试：） 答 4: 中点算法不直么?我看<计算机图形学>中的中点算法原理,应该是很直的才对,每一点都是最接近真实值的栅格点.

不过我用Bresenham,老社区有人贴过用PLM写的程序,我懒,直接找过来改成C,呵呵! 答 5: 中点法如果长度能被2整除的次数越多越直中点法如果长度能被2整除的次数越多越直
你可以用这种方法画，改变两点间的距离，很容易就能理解的，不理解也没关系，呵呵。