ImageDecoder-UIKit.swift

var uiImage: UIImage? {
    switch frameCount {
        case 0:
            return nil
        case 1:
            return staticUIImage
        default:
            return animatedUIImage
    }
}

var animatedUIImage: UIImage? {
    guard frameCount > 1 else {
        return nil
    }

    var duration: TimeInterval = 0.0
    var images: [UIImage] = []

    for i in 0..<frameCount {
        guard let image = createFrameUIImage(at: i) else {
            continue
        }

        images.append(image)
        duration += frameDuration(at: i) ?? 0.0
    }

    return UIImage.animatedImage(with: images, duration: duration)
}

var staticUIImage: UIImage? {
    frameCount > 0 ? createFrameUIImage(at: 0) : nil
}

private func createFrameUIImage(at index: Int, subsamplingLevel: SubsamplingLevel = .default, decodingOptions: DecodingOptions = .default) -> UIImage? {
    guard let cgImage = createFrameImage(at: index, subsamplingLevel: subsamplingLevel, decodingOptions: decodingOptions) else {
        return nil
    }

    return UIImage(cgImage: cgImage)
}