UIImageView实现图片水平翻转

UIImageView *_imageView = [[UIImageView alloc] initWithFrame:CGRectMake(30, 30, 200, 300)];
_imageView.backgroundColor = [UIColor clearColor];
_imageView.image = [UIImage imageNamed:@"test.png"];
_imageView.transform = CGAffineTransformMakeScale(-1, 1);
[self.view addSubview:_imageView];