[转载]【C++图形学】把一个半径为R的圆40等分，以每个等分点为圆心，以r为半径

void CMy2013_3_21_02View::OnDraw(CDC* pDC)
{
CMy2013_3_21_02Doc* pDoc = GetDocument();
ASSERT_VALID(pDoc);
// TODO: add draw code for native data here
int R1=120,r1=80;
int R2=80,r2=80;
int R3=80,r3=120;//定义大小圆的半径
double x,y;
CRect Rect;
GetClientRect(&Rect);
int MaxX=Rect.Width();
int MaxY=Rect.Height();//计算屏幕客户区高度和宽度
pDC->TextOut(0,0,'大圆半径 > 小圆半径');
pDC->TextOut(2*MaxX/5,0,'大圆半径 = 小圆半径');
pDC->TextOut(2*MaxX/3,0,'大圆半径 < 小圆半径');
CBrush NewBrush,*pOldBrush;
pOldBrush=(CBrush*)pDC->SelectStockObject(NULL_BRUSH);//使用透明画刷绘制空心圆
for(double i=0;i<=2*PI;i+=PI/20)
{
x=R1*cos(i)+MaxX/5;
y=R1*sin(i)+MaxY/2;
pDC->Ellipse(ROUND(x-r1),ROUND(y-r1),ROUND(x+r1),ROUND(y+r1));