iOS中常用的毛玻璃处理

  //1.模糊毛玻璃效果实现方案一
    //利用系统的CoreImage(滤镜)  滤镜处理的过程比较慢,会造成加载图片缓慢的现象(等一会才看到图片),尽量放到子线程执行
    UIImage *image = [UIImage imageNamed:@"1_1280x800"];
    //1.创建CIImage
    CIImage *ciImage = [[CIImage alloc] initWithImage:image];
    //2.创建滤镜CIFilter
    CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
    //3.将CIImage输入到滤镜中
    [blurFilter setValue:ciImage forKey:kCIInputImageKey];
    //4.设置模糊度
    [blurFilter setValue:@(10) forKey:@"inputRadius"];
    //5.将处理好的图片输出
    CIImage *outCiImage = [blurFilter valueForKey:kCIOutputImageKey];
    //6.CIContext (option 参数为nil代表用CPU渲染,若想用GPU渲染请查看此参数)
    CIContext *context = [CIContext contextWithOptions:nil];
    //7.获取CGImage句柄
    CGImageRef outCGImage = [context createCGImage:outCiImage fromRect:[outCiImage extent]];
    //8.获取最终的图片
    UIImage *blurImage = [UIImage imageWithCGImage:outCGImage];
    //9.释放CGImage
    CGImageRelease(outCGImage);
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
        imageView.image = blurImage;
        [self.view addSubview:imageView];

    //方案二：利用UIImage + ImageEffects 分类   下载地址：https://github.com/YouXianMing/UIImageBlur
    
    UIImage *sourceImage = [UIImage imageNamed:@"1_1280x800"];
    
    //设置模糊度
    UIImage *blurImage = [sourceImage blurImageWithRadius:10];
    
    //设置局部模糊度
    //UIImage * blurImage2 = [image blurImageAtFrame:CGRectMake(0, 0, image.size.width, image.size.height/2)];
    
    //设置灰度效果
    //UIImage * blurImage3 = [image grayScale];
    
    /*其他的一些方法,可以自己尝试使用
     固定宽度与固定高度
     - (UIImage *)scaleWithFixedWidth:(CGFloat)width;
     - (UIImage *)scaleWithFixedHeight:(CGFloat)height;
     平均的颜色
     - (UIColor *)averageColor;
     裁剪图片的一部分
     - (UIImage *)croppedImageAtFrame:(CGRect)frame;
     */
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
    imageView.image = blurImage;
    [self.view addSubview:imageView];

 //方案三:利用UIVisualEffectView(iOS8)
    // 添加展示的背景,用于显示动态模糊(背景能够滚动,便于查看动态的模糊)
    self.scrollView = [[UIScrollView alloc] initWithFrame:self.view.bounds];
    UIImageView *imageV = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"1_1280x800"]];
    self.scrollView.contentSize = imageV.image.size;
    self.scrollView.bounces = NO;
    [self.scrollView addSubview:imageV];
    [self.view addSubview:self.scrollView];
    
    //添加模糊效果
    // 1.创建模糊view
    UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]];
    
    // 2.设定模糊View的尺寸
    effectView.frame = CGRectMake(0, 100, 375, 200);
    
    // 3.添加到view当中
    [self.view addSubview:effectView];
    
    //添加显示文本
    UILabel *label = [[UILabel alloc] initWithFrame:effectView.bounds];
    label.text = @"模糊效果";
    label.font = [UIFont systemFontOfSize:40];
    label.textAlignment = NSTextAlignmentCenter;
    
    //添加模糊效果的子view
    // 1.创建出子模糊view
    UIVisualEffectView *subEffectView = [[UIVisualEffectView alloc] initWithEffect:[UIVibrancyEffect effectForBlurEffect:(UIBlurEffect *)effectView.effect]];
    
    // 2.设置子模糊view的尺寸
    subEffectView.frame = effectView.bounds;
    
    // 3.将子模糊view添加到effectView的contentView上才能显示
    [effectView.contentView addSubview:subEffectView];
    
    // 4.添加要显示的view来达到特殊效果
    [subEffectView.contentView addSubview:label];