毛玻璃效果实现（UIVisualEffectView）

UIImageView *bgView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"XXXXX"]];
    bgView.frame = self.view.frame;
    
    UIVisualEffectView *visView = [[UIVisualEffectView alloc] initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight] ];
    visView.frame = self.view.frame;
    [self.view addSubview:bgView];
    [self.view addSubview:visView];

效果：

屏幕快照 2016-07-25 下午2.29.57.png

原图：

f22c78d301857e1ce3622639dff35836.png