图像的绘制中画刷代码我们的图形如何去保存。对于我们的图形来说它是由3个要素决定的。第一个绘制的类型。由类型确定我们画的是点线矩形椭圆。还有两个点一个是起点一个是终点。只要我们按照这3个要素，就可以把这些图形保存起来，然后在OnDraw的函数中重新绘制.

要保存这3要素，类型是不相同的。在C系列的语言当中用结构体来保存不同类型的变量是比较合适的。在C++中结构体就是一个类。所以我们可以用一个类的对象保存图形的三要素。一个类的对象可以保存相关的一个图形的三要素。所以我们可以插入一个新的类。类的类型呢，选择通常的类。Generic Class

名字是CGraph ,我们为这个类定义3个成员变量：

-Brush image rendering code how to save our graphics. For graphics, it is decided by the three elements. The first type of draw. Determined by the type of painting dotted line rectangular oval. There are two points is a starting point for one end. Just follow these three elements, we can save these graphics, and then redrawn OnDraw function. Want to save these three elements is not the same type. Different types of variables to save the structure in the C family of languages ​ ​ which is more appropriate. In the structure in C++ is a class. So we can use the three elements of a class of objects saved graphics. A class can save the three elements of a graphical object. So we can insert a new class. Class type, choose the usual class. The the Generic Class name CGraph, three member variables defined for this class: