MFC两个矩形判断交集

[mineyouhe123]

看源程序过程中，看到如图中所示代码。两个矩形变量fixed和rectT，两个变量&，如果有交集，会得到一个矩形？求解释图中最后一行代码

[泥鳅不是鱼]

HRGN hRgn1 = CreateRectRgn(rc1.left, rc1.top, rc1.right, rc1.bottom);
    HRGN hRgn2 = CreateRectRgn(rc2.left, rc2.top, rc2.right, rc2.bottom);
 
    //用RGN_AND标志表示你要合并两个区域并得到交集
    HRGN hRgnSum = NULL;
    int nRet = CombineRgn(hRgnSum, hRgn1, hRgn2, RGN_AND);
    if (nRet == SIMPLEREGION)
    {        //有交集       
        //得到交集矩形
        RECT rc3;
        GetRgnBox(hRgnSum, &rc3);
    }
    else if (nRet == NULLREGION)
        //没有交集
   
    DeleteObject(hRgnSum);
    DeleteObject(hRgn2);
    DeleteObject(hRgn1);

[shen_wei]

Nonzero if CRect is empty; 0 if CRect is not empty.

[zhuyf87]

查一下MSDN，看一下CRect重载的&操作符：CRect::operator & Returns a CRect that is the intersection of CRect and rect2.

CRect operator&( 
   const RECT& rect2  
) const throw( );

Remarks The intersection is the largest rectangle that is contained in both rectangles. Both of the rectangles must be normalized or this function may fail. You can call NormalizeRect to normalize the rectangles before calling this function.