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GPUImageHistogramFilter for a still image giving null data

Very similar to this answer , except that I want to create a histogram for a still image.

Below is what I am doing and it gives a histogram with all 0 data. Is there any trick to make this work?

GPUImageFilter *filter = [[GPUImageHistogramFilter alloc]  initWithHistogramType:kGPUImageHistogramRGB];

GPUImagePicture *original = [[[GPUImagePicture alloc] initWithImage:image] autorelease];

GPUImageGammaFilter *gammaFilter = [[GPUImageGammaFilter alloc] init];
[original addTarget:gammaFilter];
[gammaFilter addTarget:filter];

GPUImageHistogramGenerator *histogramGraph = [[GPUImageHistogramGenerator alloc] init];

[histogramGraph forceProcessingAtSize:CGSizeMake(256.0, 330.0)];
[filter addTarget:histogramGraph];

GPUImageAlphaBlendFilter *blendFilter = [[GPUImageAlphaBlendFilter alloc] init];
blendFilter.mix = 0.75;
[blendFilter forceProcessingAtSize:CGSizeMake(256.0, 330.0)];

[original addTarget:blendFilter];
[histogramGraph addTarget:blendFilter];

[blendFilter addTarget:gpuImageView];

[original processImage];
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1 answer

Brad changed some internal mechanism to GPUImage to improve memory management (and it does) in recent releases, now you should tell the filter about saving the frame for still images -useNextFrameForImageCapture.

UIImage *inputImage = [UIImage imageNamed:@"Lambeau.jpg"];

GPUImagePicture *stillImageSource = [[GPUImagePicture alloc] initWithImage:inputImage];
GPUImageSepiaFilter *stillImageFilter = [[GPUImageSepiaFilter alloc] init];

[stillImageSource addTarget:stillImageFilter];
[stillImageFilter useNextFrameForImageCapture]
[stillImageSource processImage];

UIImage *currentFilteredVideoFrame = [stillImageFilter imageFromCurrentFramebuffer];
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