通过图片边角的颜色裁剪对话框圆角的例子，使用的GDIPlus，编译通不过的可以在网上下载GDIPlus的SDK,本程序对颜色比较的算法进行了优化-Color cutting through the image dialog box rounded corners example, the use of GDIPlus, build links that can be downloaded, but the SDK GDIPlus