关于内存DC的使用，这是我用的别人做的一个示例，加上一个封装好的内存dc类，使用还是比较方便，从示例程序里面可以看到非常明显的效果。-DC on the use of memory, this is someone I used to do a sample, plus a packaged memory dc class, it is quite easy to use, you can see from the example program which is very significan