mfc使用gdi+在控件中实现简单的图层操作，如图层的选择，返回图层的graphics指针，返回图层的bitmap指针等-mfc to use gdi+ control the simple layer operations, such as layer selection to return to the layers of graphics pointer return layers bitmap pointer

Gdi对象包括线条、笔刷、位图应用的演示代码。-Gdi objects including lines, brush, bitmap application demo code.