MFC编程中画园的函数Ellipse与画矩形的函数Rectangle好像都是画实心图形的，怎样画空心的呢？

话空心圆的例子
HDC hDC;
HBRUSH hBr, hOldBr;
HPEN hPen,hOldPen;
hDC=GetDC(hWnd);
hPen=::CreatePen(PS_SOLID,1,RGB(0,0,255));
hOldPen=(HPEN)SelectObject(hDC,hPen);
// Draw ellipse.
hBr = (HBRUSH) GetStockObject (NULL_BRUSH);
hOldBr = (HBRUSH) SelectObject (hDC, hBr);
Ellipse (hDC, 10, 90, 90, 170);
SelectObject (hDC, hOldBr);
删除Object (hBr);
SelectObject (hDC, hOldPen);
删除Object (hPen);
ReleaseDC(hWnd, hDC);