如何向 UIImage GPUImage 添加多个过滤器？

Question

我注意到很多人询问有关 link 使用 GPUImage 滤镜的问题。我不太清楚如何简洁地做到这一点。今晚终于搞定了。只是想分享我的代码，以便人们可以 link 找到解决方案。

Answer 1

UIImage *faceImage = [UIImage imageNamed:@"469453586_640.jpg"];
UIImageView *face = [[UIImageView alloc] initWithFrame:CGRectMake(0.0, 0.0, faceImage.size.width/2.0, faceImage.size.height/2.0)];
[face setImage:faceImage];
[self.view addSubview:face];

GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:faceImage];

GPUImageBrightnessFilter *brightnessFilter = [[GPUImageBrightnessFilter alloc] init];
[brightnessFilter setBrightness:.15];
GPUImageGrayscaleFilter *grayscaleFilter = [[GPUImageGrayscaleFilter alloc] init];

GPUImagePosterizeFilter *posterizeFilter = [[GPUImagePosterizeFilter alloc] init];
[posterizeFilter setColorLevels:1];


[stillImageSource addTarget:brightnessFilter];
[brightnessFilter addTarget:grayscaleFilter];
[grayscaleFilter addTarget:posterizeFilter];

// these need to be changed if you change the order of your filters
//    [brightnessFilter useNextFrameForImageCapture];
//    [grayscaleFilter useNextFrameForImageCapture];
[posterizeFilter useNextFrameForImageCapture];

[stillImageSource processImage];

[face setImage: [posterizeFilter imageFromCurrentFramebuffer]];