How to generate a Barcode using Swift? [duplicate] - ios

Question

I am a new iOS developer. I was wondering how can I generate a barcode in Swift.
I have the code already, there are multiple resources from where to learn how to read a barcode, but I didn't find any that talks about generating one from a string.
Thanks a lot!
P.S. I know there is a similar question about this, but it's for Objective-C. I don't know Obj-C and I find it difficult coming from .NET.

Answer 1

You could use a CoreImage (import CoreImage) filter to do that!
class Barcode {
class func fromString(string : String) -> UIImage? {
let data = string.data(using: .ascii)
if let filter = CIFilter(name: "CICode128BarcodeGenerator") {
filter.setValue(data, forKey: "inputMessage")
if let outputCIImage = filter.outputImage {
return UIImage(ciImage: outputCIImage)
}
}
return nil
}
}
let img = Barcode.fromString("whateva")
A newer version, with guard and failable initialiser:
extension UIImage {
convenience init?(barcode: String) {
let data = barcode.data(using: .ascii)
guard let filter = CIFilter(name: "CICode128BarcodeGenerator") else {
return nil
}
filter.setValue(data, forKey: "inputMessage")
guard let ciImage = filter.outputImage else {
return nil
}
self.init(ciImage: ciImage)
}
}
Usage:
let barcode = UIImage(barcode: "some text") // yields UIImage?
According to the docs :
Generates an output image representing the input data according to the
ISO/IEC 15417:2007 standard. The width of each module (vertical line)
of the barcode in the output image is one pixel. The height of the
barcode is 32 pixels. To create a barcode from a string or URL,
convert it to an NSData object using the NSASCIIStringEncoding string
encoding.

Answer 2

Improved code:
Barcode scaling
Set barcode image margin
Convert the UIImage to NSData (for some reason it wasn't possible with the code above).
It won't fail when sharing the barcode image (probably because of the same bug)
Swift 3
func generateBarcode(from string: String) -> UIImage? {
let data = string.data(using: String.Encoding.ascii)
if let filter = CIFilter(name: "CICode128BarcodeGenerator") {
filter.setDefaults()
//Margin
filter.setValue(7.00, forKey: "inputQuietSpace")
filter.setValue(data, forKey: "inputMessage")
//Scaling
let transform = CGAffineTransform(scaleX: 3, y: 3)
if let output = filter.outputImage?.applying(transform) {
let context:CIContext = CIContext.init(options: nil)
let cgImage:CGImage = context.createCGImage(output, from: output.extent)!
let rawImage:UIImage = UIImage.init(cgImage: cgImage)
//Refinement code to allow conversion to NSData or share UIImage. Code here:
//http://stackoverflow.com/questions/2240395/uiimage-created-from-cgimageref-fails-with-uiimagepngrepresentation
let cgimage: CGImage = (rawImage.cgImage)!
let cropZone = CGRect(x: 0, y: 0, width: Int(rawImage.size.width), height: Int(rawImage.size.height))
let cWidth: size_t = size_t(cropZone.size.width)
let cHeight: size_t = size_t(cropZone.size.height)
let bitsPerComponent: size_t = cgimage.bitsPerComponent
//THE OPERATIONS ORDER COULD BE FLIPPED, ALTHOUGH, IT DOESN'T AFFECT THE RESULT
let bytesPerRow = (cgimage.bytesPerRow) / (cgimage.width * cWidth)
let context2: CGContext = CGContext(data: nil, width: cWidth, height: cHeight, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: cgimage.bitmapInfo.rawValue)!
context2.draw(cgimage, in: cropZone)
let result: CGImage = context2.makeImage()!
let finalImage = UIImage(cgImage: result)
return finalImage
}
}
return nil
}

Answer 3

If your deployment target is at least iOS 8, you can use Core Image. Here is my BarcodeGenerator class (you need to import CoreImage):
class BarcodeGenerator {
enum Descriptor: String {
case code128 = "CICode128BarcodeGenerator"
case pdf417 = "CIPDF417BarcodeGenerator"
case aztec = "CIAztecCodeGenerator"
case qr = "CIQRCodeGenerator"
}
class func generate(from string: String,
descriptor: Descriptor,
size: CGSize) -> CIImage? {
let filterName = descriptor.rawValue
guard let data = string.data(using: .ascii),
let filter = CIFilter(name: filterName) else {
return nil
}
filter.setValue(data, forKey: "inputMessage")
guard let image = filter.outputImage else {
return nil
}
let imageSize = image.extent.size
let transform = CGAffineTransform(scaleX: size.width / imageSize.width,
y: size.height / imageSize.height)
let scaledImage = image.transformed(by: transform)
return scaledImage
}
}
It can be used like this
BarcodeGenerator.generate(from: "barcode-string",
descriptor: .code128,
size: CGSize(width: 800, height: 300))

Answer 4

Use like this,
func createBarcodeFromString(barcode:String)->UIImage?{
let data = self.data(using: .isoLatin1)
guard let filter = CIFilter(name: "CICode128BarcodeGenerator") else {
return nil
}
filter.setValue(data, forKey: "inputMessage")
filter.setValue(7.0, forKey:"inputQuietSpace")
guard var ciImage = filter.outputImage else {
return nil
}
let imageSize = ciImage.extent.integral
let outputSize = CGSize(width:320, height: 60)
ciImage = ciImage.transformed(by:CGAffineTransform(scaleX: outputSize.width/imageSize.width, y: outputSize.height/imageSize.height))
let image = convertCIImageToUIImage(ciimage: ciImage)
return image
}
func convertCIImageToUIImage(ciimage:CIImage)->UIImage{
let context:CIContext = CIContext.init(options: nil)
let cgImage:CGImage = context.createCGImage(ciimage, from: ciimage.extent)!
let image:UIImage = UIImage.init(cgImage: cgImage)
return image
}