How can I generate a barcode from a string in Swift?
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))
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
}
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.
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
}