gpuimage使用

CFAbsoluteTime elapsedTime, startTime = CFAbsoluteTimeGetCurrent();

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

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

UIImage *currentFilteredVideoFrame = [stillImageFilter imageFromCurrentFramebuffer];

elapsedTime = CFAbsoluteTimeGetCurrent() - startTime;
processingTimeForGPUImageRoutine = elapsedTime * 1000.0;

return currentFilteredVideoFrame;