想看一看我们要实现的效果

原图.png

效果图.png

//原图  
 UIImage * inputImage = [UIImage imageNamed:@"IMG_0160.jpg"];
    //使用滤镜（滤镜的名称反色等）
    GPUImageColorInvertFilter *disFilter = [[GPUImageColorInvertFilter alloc] init];
    // disFilter.crosshairWidth = 100;
   // [disFilter setCrosshairColorRed:1 green:0 blue:0];
    //设置要渲染的区域
    [disFilter forceProcessingAtSize:inputImage.size];
    [disFilter useNextFrameForImageCapture];
    
    //获取数据源
    GPUImagePicture *stillImageSource = [[GPUImagePicture alloc]initWithImage:inputImage];
    
    //添加上滤镜
    [stillImageSource addTarget:disFilter];
    //开始渲染
    [stillImageSource processImage];
    //获取渲染后的图片
    UIImage *newImage = [disFilter imageFromCurrentFramebuffer];
    //加载出来
    UIImageView *imageView = [[UIImageView alloc] initWithImage:newImage];
    imageView.frame = CGRectMake(50,50,inputImage.size.width ,inputImage.size.height);
    [self.view addSubview:imageView];