如何从Swift中的字符串生成条形码？

Question

我是一个新的iOS开发人员.我想知道如何在Swift中生成条形码.

我已经有了代码,有多个资源可以从哪里学习如何读取条形码,但我没有找到任何关于从字符串生成一个的讨论.

非常感谢!

PS我知道有一个类似的问题,但它适用于Objective-C.我不知道Obj-C,我发现很难从.NET中获取.

Answer 1

你可以使用CoreImage(import CoreImage)过滤器来做到这一点!

    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")

根据文件:

根据ISO/IEC 15417:2007标准生成表示输入数据的输出图像.输出图像中条形码的每个模块(垂直线)的宽度是一个像素.条形码的高度为32像素.要从字符串或URL创建条形码,请使用NSASCIIStringEncoding字符串编码将其转换为NSData对象.

Answer 2

改进代码:

• 条形码缩放
• 设置条形码图像边距
• 将UIImage转换为NSData(出于某种原因,上面的代码无法实现).
• 共享条形码图像时不会失败(可能是因为同一个bug)

斯威夫特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

如果您的部署目标至少是iOS 8,则可以使用Core Image.这是我的BarcodeGenerator类(您需要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
    }
}

它可以像这样使用

BarcodeGenerator.generate(from: "barcode-string", 
                     symbology: .code128, 
                          size: CGSize(width: 800, height: 300))