Capturing still image from camera using gpuimage2 - ios

Question

I have a photo/gif app I made previously using AVFoundation as a base for the camera and taking photos, but I wanted to upgrade it to add some live filtering and post capture filtering too.
After some digging I found gpuimage/gpuimage2 and since my project is in swift 3 I started replacing my previous camera module with gpuimage.
I got the camera to work again but I have issues capturing a photo from the camera to store it as a uiimage until it is uploaded to a server.
do {
self.videoCamera = try Camera(sessionPreset: AVCaptureSessionPresetPhoto, location: .frontFacing)
} catch {
self.videoCamera = nil
print("Couldn't initialize camera with error: \(error)")
}
this is my init and then this is where I place the camera feed in the view
self.filterView!.frame = self.view.frame
self.filterView!.orientation = .portraitUpsideDown
self.filterView!.fillMode = .preserveAspectRatioAndFill
self.videoCamera! --> self.filterView!
self.videoCamera!.startCapture()
as you can see for the moment I don't want to use any filters, I'm trying to first get the basic functionality back (i.e. showing a camera feed the taking 1-5 images in a row)
I noticed there was a saveNextFrameToURL but it saves the file on the device but I only want the uiimage so this is what I put to replace the content of my takePhoto method (images is nil on first run)
func takePhoto(){
if self.images == nil {
self.images = []
}
let pictureOutput = PictureOutput()
pictureOutput.encodedImageFormat = .jpeg
pictureOutput.imageAvailableCallback = {image in
self.images!.append(image)
}
self.videoCamera! --> pictureOutput
}
My issue is that imageAvailableCallback is simply never called (I tried placing a breakpoint in it but nothing) whereas it goes through the rest of the method not raising any errors or warning.
what am I doing wrong ? is it even possible to capture a still image from a non filtered view ? if so how can I add a filter that would not change the image as such so I can still do some unedited photo capture in my app?
I've been going at it for over 2 weeks now and every time I search if anyone had the same issue I only find issues about editing a still image or a filtered image and when I tried filtering the image as such:
self.filterView!.frame = self.view.frame
self.filterView!.orientation = .portraitUpsideDown
self.filterView!.fillMode = .preserveAspectRatioAndFill
self.baseFilter = BrightnessAdjustment()
self.videoCamera! --> self.baseFilter --> self.filterView!
self.videoCamera!.startCapture()
and the takePhoto method
func takePhoto(){
if self.images == nil {
self.images = []
}
let pictureOutput = PictureOutput()
pictureOutput.encodedImageFormat = .jpeg
pictureOutput.imageAvailableCallback = {image in
self.images!.append(image)
}
self.baseFilter! --> pictureOutput
}
I get a white screen instead of my camera feed and still no image.
Any help would be appreciated thank you

Answer 1

I found where my problem was by looking at similar issues and the comments (found one where Brad Larson commented here
Basically it has to do with the lifespan of my pictureOutput variable, since it was enclosed inside a method is didn't last long enough for the callback to be made and to save the image, by making my pictureOutput variable a class variable I solved my issues