import MapleBacon

private var imageView: UIImageView!

func someFunc() {
  let url = URL(string: "…")
  imageView.setImage(with: url)
}

func someFunc() {
  let url = URL(string: "…")
  imageView.setImage(with: url, placeholder: UIImage(named: "placeholder"))
}

func someFunc() {
  let url = URL(string: "…")
  imageView.setImage(with: url, displayOptions: .downsampled)
}

private class SepiaImageTransformer: ImageTransforming {

  // The identifier is used as part of the cache key. Make sure it's something unique
  let identifier = "com.schnaub.SepiaImageTransformer"

  func transform(image: UIImage) -> UIImage? {
    let filter = CIFilter(name: "CISepiaTone")!

    let ciImage = CIImage(image: image)
    filter.setValue(ciImage, forKey: kCIInputImageKey)
    filter.setValue(0.5, forKey: kCIInputIntensityKey)

    let context = CIContext()
    guard let outputImage = filter.outputImage,
          let cgImage = context.createCGImage(outputImage, from: outputImage.extent) else {
            return image
    }

    // Return the transformed image which will be cached (or used by another transformer)
    return UIImage(cgImage: cgImage)
  }

}

let url = URL(string: "…")
let transformer = SepiaImageTransformer()
imageView.setImage(with: url, transformer: transformer)

let chainedTransformer = SepiaImageTransformer()
  .appending(transformer: DifferentTransformer())
  .appending(transformer: AnotherTransformer())

let chainedTransformer = SepiaImageTransformer() >>> DifferentTransformer() >>> AnotherTransformer()

let oneDaySeconds: TimeInterval = 60 * 60 * 24
MapleBacon.default.maxCacheAgeSeconds = oneDaySeconds

MapleBacon.shared.image(with: url)
  .receive(on: DispatchQueue.main) // Dispatch to the right queue if updating the UI
  .sink(receiveValue: { image in
    // Do something with your image
  })
  .store(in: &subscriptions) // Hold on to and dispose your subscriptions