【计算机图形学】圆的中点算法

//在CCcView里 添加头文件 #include "DiagCC.h"

//定义类的对象  DiagCC dcc;


/////////////////////////////////////////////////////////////////////////////
// CCcView message handlers

void CCcView::CirclePoint(int x, int y, int r, int g, int b)
{  CClientDC dc(this);
    int x0,y0;
    x0=dcc.m_px;
    y0=dcc.m_py;
    dc.SetPixel(x+x0,y+y0,RGB(r,g,b)); 
    dc.SetPixel(y+y0+x0-y0,x+x0+y0-x0,RGB(0,0,255)); 
    dc.SetPixel(x+x0,-y+y0,RGB(r,g,b)); 
    dc.SetPixel(-y+y0+x0-y0,x+x0+y0-x0,RGB(0,255,0)); 
    dc.SetPixel(-x+x0,y+y0,RGB(r,g,b)); 
    dc.SetPixel(y+y0+x0-y0,-x+x0+y0-x0,RGB(255,0,0)); 
    dc.SetPixel(-x+x0,-y+y0,RGB(r,g,b)); 
    dc.SetPixel(-y+y0+x0-y0,-x+x0+y0-x0,RGB(r,g,b)); 
}

void CCcView::OnDrawcc() 
{     // TODO: Add your command handler code here
 
  int x0,y0,radius;
  if(dcc.DoModal()==IDOK)
  {    radius=dcc.m_r;
    x0=dcc.m_px;
    y0=dcc.m_py;
  }
  //mid-point
  float d;
  int x,y;
  x=0;
  y=radius;
  d=5.0/4-radius;//初始化
  CirclePoint(x+x0,y+y0,dcc.m_CR,dcc.m_CG,dcc.m_CB);
 while(y>x)
 {
 if(d<=0)   d+=2.0*x+3;
 else
  {d+=2.0*(x-y)+5;
   y--;
  }
 x++;
 CirclePoint(x,y,dcc.m_CR,dcc.m_CG,dcc.m_CB);
}//end of while

}