UIImage Extension for Swift

UIImage+Project.swift

extension UIImage {
    
    /// Merging two images into one
    class func imageByCombiningImage(firstImage: UIImage, withImage secondImage: UIImage) -> UIImage {
        
        let newImageWidth  = max(firstImage.size.width,  secondImage.size.width )
        let newImageHeight = max(firstImage.size.height, secondImage.size.height)
        let newImageSize = CGSize(width : newImageWidth, height: newImageHeight)

        UIGraphicsBeginImageContextWithOptions(newImageSize, false, UIScreen.main.scale)
        
        let firstImageDrawX  = round((newImageSize.width  - firstImage.size.width  ) / 2)
        let firstImageDrawY  = round((newImageSize.height - firstImage.size.height ) / 2)
        
        let secondImageDrawX = round((newImageSize.width  - secondImage.size.width ) / 2)
        let secondImageDrawY = round((newImageSize.height - secondImage.size.height) / 2)
        
        firstImage .draw(at: CGPoint(x: firstImageDrawX,  y: firstImageDrawY))
        secondImage.draw(at: CGPoint(x: secondImageDrawX, y: secondImageDrawY))
        
        let image = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
      
        return image!
    }
    
    /// Get Average `UIColor` from UIImage
    var averageColor: UIColor? {
        guard let inputImage = CIImage(image: self) else { return nil }
        let extentVector = CIVector(x: inputImage.extent.origin.x, y: inputImage.extent.origin.y, z: inputImage.extent.size.width, w: inputImage.extent.size.height)
        
        guard let filter = CIFilter(name: "CIAreaAverage", withInputParameters: [kCIInputImageKey: inputImage, kCIInputExtentKey: extentVector]) else { return nil }
        guard let outputImage = filter.outputImage else { return nil }
        
        var bitmap = [UInt8](repeating: 0, count: 4)
        let context = CIContext(options: [kCIContextWorkingColorSpace: kCFNull])
        context.render(outputImage, toBitmap: &bitmap, rowBytes: 4, bounds: CGRect(x: 0, y: 0, width: 1, height: 1), format: kCIFormatRGBA8, colorSpace: CGColorSpaceCreateDeviceRGB())
        
        return UIColor(red: CGFloat(bitmap[0]) / 255, green: CGFloat(bitmap[1]) / 255, blue: CGFloat(bitmap[2]) / 255, alpha: (CGFloat(bitmap[3]) / 255))
    }
}