说明：  Dib类的封装，因为MFC中不提供任何Dib的支持，为了方便复用，这里设计一个Dib类，这个类的封装十分复杂，这里采取分而治之的方法，对关键部分进行了单独讲解。
(Dib type of package, because MFC does not provide any support Dib, in order to facilitate reuse, where the design of a Dib category, this type of package is very complex, here taken to divide and conquer approach, a key part of a separate brief.)