Java. BarCode Ean-13 to String

Question

I have a project, that draws a price tag, which has a barcode in it. To draw a barcode i use a JLabel with EAN-13 font set in. The input data, from which the price tag is generated, consists of two barcode attributes: the barcode number

080432402184 for example

and the encoded version, which is passed to the previosly mentioned JLabel

!h04324|PRQXTp for that barcode number

The problem is that i dont have access to the code, which generates the encoded version, and the algorithm that generates it has bugs. Because of that i want to write that thing from scrap, but having trouble finding the encoding algorithm.

Can someone point me to where i can find instructions on encoding it? Thanks.

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The Barcode4J problem. Trying to create a Graphics2D object and draw a barcode on it(cant really use a file out, because the barcode is only a part of the price tag).

Trying to do this using Java2DCanvasProvider:

EAN13Bean bean = new EAN13Bean();

    final int dpi = 150;

    //Configure the barcode generator
    bean.setModuleWidth(UnitConv.in2mm(13.3f / dpi)); //makes the narrow bar 
                                                     //width exactly one pixel
    bean.doQuietZone(true);

    bean.setHeight(chart.getBarcodeMainHeight()-10);
    bean.setFontSize(10f);

    BufferedImage bi = new BufferedImage(chart.getBarcodeMainWidth(), chart.getBarcodeMainHeight(), BufferedImage.TYPE_INT_RGB);
    Graphics2D graphics = bi.createGraphics();

    //graphics.fillRect(0, 0, chart.getBarcodeMainWidth(), chart.getBarcodeMainHeight());
    Java2DCanvasProvider canv = new Java2DCanvasProvider(graphics, 0);

    bean.generateBarcode(canv, priceTag.getBarCodeNumber());

    barCodeLabel.setIcon(new ImageIcon(bi));

but i recieve an inverted image block(i'm really new to Graphics2D).

Answer 1

For those who may need this, finally found the algorithm(in C, but rewrote it in Java).

public class BarCodeService {
    private static final int[][] leftPartMaps = {{48,48,48,48,48},{48,64,48,64,64},{48,64,64,48,64},{48,64,64,64,48},{64,48,48,64,64},{64,64,48,48,64},{64,64,64,48,48},{64,48,64,48,64},{64,48,64,64,48},{64,64,48,64,48}};
    private static final int[] rightPartMap = {80,80,80,80,80,112};
    private static final int firstDigitArg = 33, secondDigitArg = 96;
    private static final char delimiter = 124;


    public String parseInput(String code){
        char[] data = new char[13];
        char[] givenData = code.toCharArray();

        int length = (givenData.length < 12) ? givenData.length : 12;
        System.arraycopy(givenData, 0, data, 0, length);

        int checkSumDigit = generateCheckSum(data);
        data[12] = String.valueOf(checkSumDigit).charAt(0);

        return String.valueOf(data);
    }

    public String generateCode(String code){
        char[] data = code.toCharArray();
        if(data.length<13){
            System.err.println("Bad data input");
            return null;
        }

        String result = null;
        try{
            result = generateEanString(data);
        }catch(NumberFormatException e){
            System.err.println("Input data had unconvertable characters: "+e.fillInStackTrace());
            result = "";
        }
        return result;
    }

    protected int generateCheckSum(char[] data){
        int result = 0;
        for(int i = 0; i<12;i++){
            int num = Character.getNumericValue(data[i]); 
            num = (i%2 == 0) ? num : num*3;
            result += num;
        }

        result = (result % 10 == 0) ? 0 : ((result/10)+1)*10 - result;
        return result;
    }
    protected String generateEanString(char[] data) throws NumberFormatException{
        char[] resultData = new char[14];

        resultData[0] = (char) (Character.getNumericValue(data[0]) + firstDigitArg);
        resultData[1] = (char) (Character.getNumericValue(data[1]) + secondDigitArg);


    fillLeftPart(data,resultData);
    resultData[7] = delimiter;
    fillRightPart(data,resultData);

    return String.valueOf(resultData);
}

protected void fillLeftPart(char[] inputData, char[] resultData){
    int[] chars = new int[]{
            Character.getNumericValue(inputData[2]),
            Character.getNumericValue(inputData[3]),
            Character.getNumericValue(inputData[4]),
            Character.getNumericValue(inputData[5]),
            Character.getNumericValue(inputData[6])
    };

    int pointer = Character.getNumericValue(inputData[0]);
    for(int i = 0; i<leftPartMaps[pointer].length; i++){
        int n = i+2;
        resultData[n] = (char)(chars[i] + leftPartMaps[pointer][i]);
    }

}

protected void fillRightPart(char[] inputData, char[] resultData){
    int[] chars = new int[]{
        Character.getNumericValue(inputData[7]),
        Character.getNumericValue(inputData[8]),
        Character.getNumericValue(inputData[9]),
        Character.getNumericValue(inputData[10]),
        Character.getNumericValue(inputData[11]),
        Character.getNumericValue(inputData[12])
    };

    for(int i = 0; i< rightPartMap.length; i++){
        int n = i + 8;
        resultData[n] = (char)(chars[i] + rightPartMap[i]);
    }
}

public static void main(String[] args) {
    /*System.out.println((char)(Character.getNumericValue('4')+33));
    System.out.println((char)((int)('a')+2));
    System.out.println((int)'%');
    System.out.println("'"+(char)'0'+"'");*/
    //if(true)return;
    // %hB00FB|PUPWVp 4820062050760
    //"%hB00FB|PUQUUr";"4820062051552";
    String testCode = "2205276000000";
    BarCodeService serv = new BarCodeService();
    String parsedString = serv.parseInput(testCode);
    System.out.println("Input: "+testCode+ ", parsed string: "+parsedString);
    String barCodeString = serv.generateCode(parsedString);
    System.out.println("Result: "+barCodeString);
}

}

My input was from a String, and had bad checksum digits, so the char[] structure was used on purpose.

Answer 2

Barcode4J has your back on this. It can also generate the images, so you can let go of the JLabel and the special font.