用CDC画椭圆实现,圆是特殊的椭圆而已。
- void DrawCircle(CDC* pDC,CRect rect)
- {
- int rx,ry;
- //找出大一些的直径
- if (rect.right < rect.left)
- {
- rx= rect.left;
- rect.left = rect.right;
- rect.right = rx;
- }
- if (rect.bottom < rect.top)
- {
- ry= rect.top;
- rect.top = rect.bottom;
- rect.bottom = ry;
- }
- //算出两直径的差
- rx= rect.right - rect.left;
- ry= rect.bottom - rect.top;
- //根据直径差值,移动椭圆的边界,圆的半径为min(x,y)
- if (rx > ry)
- {
- rect.left += (rx-ry) / 2;
- rect.right = rect.left + ry;
- }
- else
- {
- rect.top += (ry-rx) / 2;
- rect.bottom = rect.top + rx;
- }
- pDC->Ellipse(rect);
- }
还有个简单点的方法,这样更实用。就是算出圆的半径radius,矩形坐上角坐标(x,y),则画圆的语句为:
- pDC->(x-radius,y-radius,x+radius,y+radius)
转载出处:http://blog.youkuaiyun.com/beyondhaven/article/details/5870007