VIPhotoView 介绍
VIPhotoView 实现图片的基本浏览功能。能够双击放大，拉伸放大等。的确能够减少相当一部分的代码量。
示例代码：
- (void)viewDidLoad {
[super viewDidLoad];
UIImage *image = [UIImage imageNamed:@"test.jpg"];
VIPhotoView *photoView = [[VIPhotoView alloc] initWithFrame:self.view.bounds andImage:image];
photoView.autoresizingMask = (1 << 6) -1;
[self.view addSubview:photoView];
}