Question

求教关于一个CRect类型转换的问题

Answer 1

MFC不会使用

1.重载了operator+=函数。
rc+=CRect(10,0,-10,0);MFC实现是这样的顺序
构造
ATLTYPES_INLINE CRect::CRect(int l, int t, int r, int b) throw()
{ left = l; top = t; right = r; bottom = b; }

转换
ATLTYPES_INLINE CRect::operator LPRECT() throw()
{ return this; }

ATLTYPES_INLINE void CRect::operator+=(LPCRECT lpRect) throw()
{ InflateRect(lpRect); }

ATLTYPES_INLINE void CRect::InflateRect(LPCRECT lpRect) throw()
{
left -= lpRect->left; top -= lpRect->top;
right += lpRect->right; bottom += lpRect->bottom;
}

看看这个operator+=是怎么计算的