HDC hMemDC;//内存DC,可以有效提高绘图效率,避免屏幕闪烁
hMemDC = CreateCompatibleDC(NULL);//创建与设备兼容的内存DC
HDC hSrcDC;
hSrcDC = CreateCompatibleDC(NULL)//创建存放位图的设备缓冲
HBITMAP bmpsource=LoadImage(NULL,bmpstr,IMAGE_BITMAP,with,height,LR_LOADFROMFILE);
SelectObject(hSrcDC,bmpsource);
BitBlt(hMemDC,x1,y1,with,height,hSrcDC,x2,y2,SRCCOPY);//将位图显示到后备缓冲
BitBlt(hDC,x1,y1,with,height,hMemDC,x2,y2,SRCCOPY);//将后备缓冲显示到屏幕