using_ios_gan.swift

// resize gan example   

func upscaleImage(_ orgImage: NSImage) -> NSImage {
        let newSize = CGSize(width: 2048, height: 2048)
        guard let cgImage = orgImage.cgImage(forProposedRect: nil, context: nil, hints: nil),
            let resizedImage = resize(cgImage, to: newSize) else {
            return orgImage
        }

        guard let model = try? VNCoreMLModel(for: realesrgan512(configuration: MLModelConfiguration()).model) else {
            fatalError("model initialization failed")
        }
        
        let coreMLRequest = VNCoreMLRequest(model: model)
        coreMLRequest.imageCropAndScaleOption = .scaleFill
        let handler = VNImageRequestHandler(cgImage: resizedImage)
        try? handler.perform([coreMLRequest])
  
        guard let result = coreMLRequest.results?.first as? VNPixelBufferObservation else {
            return orgImage
        }
        
        let ciContext = CIContext()
        let ciImage = CIImage(cvImageBuffer: result.pixelBuffer)
        guard let upImage =  ciContext.createCGImage(ciImage, from: ciImage.extent) else {
               return orgImage
        }
        let nsImage = NSImage(cgImage: upImage, size: NSZeroSize)
        
        return nsImage
    }

func resize(_ image: CGImage, to newSize: CGSize) -> CGImage? {
    let bitmapInfo: UInt32 = CGBitmapInfo.byteOrder32Big.rawValue | CGImageAlphaInfo.premultipliedLast.rawValue
    
    guard let context = CGContext(
            data: nil,
            width: Int(newSize.width),
            height: Int(newSize.height),
            bitsPerComponent: 8,
            bytesPerRow: 0,
            space: CGColorSpaceCreateDeviceRGB(),
            bitmapInfo: bitmapInfo
    ) else { return nil }

    context.interpolationQuality = .high
    context.draw(image, in: CGRect(origin: .zero, size: newSize))
    return context.makeImage()
}