Generate Aztec barcode of necessary shape in .NET

Blog category: Barcode

June 03, 2020

At some point it can be necessary to generate a barcode and encode into it the data, which size exceeds the capacity of barcode, making impossible to put all the data into one barcode. To solve this problem, you should divide the source data into several data blocks and encode these data blocks into several barcodes. You also will have to mark the data blocks so that they can be united back into the source data.

There is Structure Append technology for two-dimensional barcodes, which allows you to divide the source data into data blocks and get back the original data from these data blocks.
Structure Append technology for DataMatrix and QR Code barcodes allows you to split the source data up to 16 data blocks and encode these data blocks into 16 DataMatrix or QR Code barcodes.
For Aztec barcodes you can split the source data up to 26 data blocks and encode them into 26 Aztec barcodes.
For PDF417 barcodes the Structure Append technology allows you to split the source data to 99999 data blocks.
And for Code16K barcodes the Structure Append technology allows 9 data blocks.

Each barcode with a data block contains the position of the data block in the source data, so barcodes with data blocks in the image can be arranged in random order. This feature can be used to place barcodes on an image in most optimal way.

Here is C# code that allows you to generate an Aztec barcode with text "VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android.":
/// <summary>
/// Generates Aztec barcode as raster image.
/// </summary>
public void GenerateAztecBarcode()
{
    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // set barcode writer settings
    barcodeWriter.Settings.Barcode = Vintasoft.Barcode.BarcodeType.Aztec;
    barcodeWriter.Settings.Value = "VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android.";

    // get barcode as image
    using (System.Drawing.Image barcodeImage = barcodeWriter.GetBarcodeAsBitmap())
    {
        // save the barcode image to a file
        barcodeImage.Save("aztec-barcode.png");
    }
}

Here is the image of generated Aztec barcode:
Aztec barcode

Here is C# code that allows you to read data encoded into generated Aztec barcode:
/// <summary>
/// Recognizes Aztec barcode in image.
/// </summary>
/// <param name="barcodeImageFilePath">A path to a barcode image file.</param>
public void RecognizeAztecBarcode()
{
    // create barcode reader
    using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
    {
        // specify that reader must search for Aztec barcodes
        reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Aztec;

        // specify that reader must search for horizontal barcodes only
        reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal;

        // read barcodes from image file
        Vintasoft.Barcode.IBarcodeInfo[] barcodeInfos = reader.ReadBarcodes("aztec-barcode.png");

        // if barcodes are not detected
        if (barcodeInfos.Length == 0)
        {
            System.Console.WriteLine("Barcodes are not found.");
        }
        // if barcodes are detected
        else
        {
            // get information about recognized barcodes

            System.Console.WriteLine(string.Format("{0} barcode(s) found:", barcodeInfos.Length));
            System.Console.WriteLine();
            for (int i = 0; i < barcodeInfos.Length; i++)
            {
                Vintasoft.Barcode.IBarcodeInfo barcodeInfo = barcodeInfos[i];
                System.Console.WriteLine(string.Format("[{0}:{1}]", i + 1, barcodeInfo.BarcodeType));
                System.Console.WriteLine(string.Format("Value:      {0}", barcodeInfo.Value));
                System.Console.WriteLine(string.Format("Region:     {0}", barcodeInfo.Region));
                System.Console.WriteLine();
            }
        }
    }
}

Here is the result of reading data from generated Aztec barcode:
1 barcode(s) found:

[1:Aztec]
Value: VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android.


The Aztec barcode has a square shape and this may cause a non-optimal use of space in the image if the barcode should be placed in a rectangular region.

So next we divide the text of the barcode into 4 data blocks, instead of one barcode, we create 4 barcodes and place these 4 barcodes horizontally in order to optimally use the space of rectangular shape intended for positioning the barcode.

Here is C# code that allows to divide the text "VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android." into 4 data blocks, generate 4 Aztec barcodes with these data blocks and place Aztec barcodes horizontally:
/// <summary>
/// Generates several Aztec barcodes with structure append information and aligns barcodes horizontally.
/// </summary>
public void GenerateAztecBarcodesWithStructureAppendAndAlignBarcodeHorizontally()
{
    // source text
    string text = "VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android.";
    
    // count of text blocks
    int textBlockCount = 4;

    // maximum length of text block
    int textBlockLen = text.Length / textBlockCount;
    if ((text.Length % textBlockCount) != 0)
        textBlockLen++;

    // array with barcode images
    System.Drawing.Image[] barcodeImages = new System.Drawing.Image[textBlockCount];
    // for each text block
    for (int i = 0; i < textBlockCount; i++)
    {
        // calculate text block string

        string textBlock = text.Substring(0, textBlockLen);
        text = text.Substring(textBlockLen);

        // generate barcode image with text block
        barcodeImages[i] = GenerateImageOfAztecBarcodeWithStructureAppendInformation(textBlock, i + 1, textBlockCount);
    }

    // width of image with merged barcodes
    int mergedBarcodeWidth = 0;
    // for each barcode image
    for (int i = 0; i < barcodeImages.Length; i++)
    {
        // increase width of image with merged barcodes
        mergedBarcodeWidth += barcodeImages[i].Width;
    }

    // calculate height of image with merged barcodes
    int mergedBarcodeHeight = barcodeImages[0].Height;

    // create image with merged barcodes
    using (System.Drawing.Image mergedBarcodesImage = new System.Drawing.Bitmap(mergedBarcodeWidth, mergedBarcodeHeight))
    {
        // create Graphics for drawing on image with merged barcodes
        using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(mergedBarcodesImage))
        {
            // fill image with merged barcodes using white color
            g.FillRectangle(System.Drawing.Brushes.White, new System.Drawing.RectangleF(0, 0, mergedBarcodesImage.Width, mergedBarcodesImage.Height));

            // the horizontal position of barcode image on image with merged barcodes
            int barcodeXPosition = 0;
            // for each barcode image
            for (int i = 0; i < barcodeImages.Length; i++)
            {
                // draw barcode image on image with merged barcodes
                g.DrawImage(barcodeImages[i], new System.Drawing.PointF(barcodeXPosition, 0));

                // change the horizontal position of barcode image on image with merged barcodes
                barcodeXPosition += barcodeImages[i].Width;
            }
        }

        // save image with merged barcodes to a file
        mergedBarcodesImage.Save("aztec-barcodes-with-structure-append-and-aligned-horizontally.png");
    }

    // for each barcode image
    for (int i = 0; i < barcodeImages.Length; i++)
    {
        // dispose barcode image
        barcodeImages[i].Dispose();
    }
}

/// <summary>
/// Generates an image of Aztec barcode, which contains information about the structure append.
/// </summary>
/// <param name="barcodeValue">Barcode value.</param>
/// <param name="symbolPosition">Value position in structure append. Value from 1 to <i>symbolCount</i>.</param>
/// <param name="symbolCount">Count of values in structure append.</param>
/// <returns>An image of Aztec barcode, which contains information about the structure append.</returns>
public System.Drawing.Image GenerateImageOfAztecBarcodeWithStructureAppendInformation(string barcodeValue, int symbolPosition, int symbolCount)
{
    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // specify that Aztec barcode must be created
    barcodeWriter.Settings.Barcode = Vintasoft.Barcode.BarcodeType.Aztec;

    // specify that created Aztec barcode should not have padding
    barcodeWriter.Settings.Padding = 0;

    // specify the barcode values
    barcodeWriter.Settings.ValueItems = new Vintasoft.Barcode.BarcodeInfo.ValueItemBase[] {
        // create the non-data flag that contains information about structure append
        Vintasoft.Barcode.BarcodeInfo.NonDataFlags.CreateAztecStructuredAppendCharacter(symbolPosition, symbolCount, null),
        // create a text value item
        new Vintasoft.Barcode.BarcodeInfo.TextValueItem(barcodeValue)
    };

    // return generated barcode image
    return barcodeWriter.GetBarcodeAsBitmap();
}

Here is the image of generated Aztec barcodes with data blocks:
Aztec barcodes with Structure Append and aligned horizontally

The image containing Aztec barcodes with data blocks has rectangular shape and thus can be optimally deployed into a rectangular region.

Here is C# code that allows to recognize data from generated Aztec barcodes and unite the data blocks into original data:
/// <summary>
/// Recognizes Aztec barcodes with structure append information.
/// </summary>
/// <param name="barcodeImageFilePath">A path to a barcode image file.</param>
public void RecognizeAztecBarcodesWithStructureAppend()
{
    // create barcode reader
    using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
    {
        // specify that reader must search for Aztec barcodes
        reader.Settings.ScanBarcodeTypes = Vintasoft.Barcode.BarcodeType.Aztec;

        // specify that reader must search for horizontal barcodes only
        reader.Settings.ScanDirection = Vintasoft.Barcode.ScanDirection.Horizontal;

        // read barcodes from image file
        Vintasoft.Barcode.IBarcodeInfo[] barcodeInfos = reader.ReadBarcodes("aztec-barcodes-with-structure-append-and-aligned-horizontally.png");

        // if barcodes are not detected
        if (barcodeInfos.Length == 0)
        {
            System.Console.WriteLine("Barcodes are not found.");
        }
        // if barcodes are detected
        else
        {
            // reconstruct barcode info from barcode infos with structure append information
            Vintasoft.Barcode.BarcodeInfo.StructuredAppendBarcodeInfo[] reconstructedBarcodeInfos =
                Vintasoft.Barcode.BarcodeInfo.StructuredAppendBarcodeInfo.ReconstructFrom(barcodeInfos);

            // get information about recognized barcodes

            System.Console.WriteLine(string.Format("{0} reconstructed barcode(s) found:", reconstructedBarcodeInfos.Length));
            System.Console.WriteLine();
            for (int i = 0; i < reconstructedBarcodeInfos.Length; i++)
            {
                Vintasoft.Barcode.BarcodeInfo.StructuredAppendBarcodeInfo reconstructedBarcodeInfo = reconstructedBarcodeInfos[i];
                System.Console.WriteLine(string.Format("[{0}:{1}]", i + 1, reconstructedBarcodeInfo.BarcodeType));
                System.Console.WriteLine(string.Format("Value:      {0}", reconstructedBarcodeInfo.Value));
                System.Console.WriteLine();
            }
        }
    }
}

Here is the result of recognition from generated Aztec barcodes with data blocks:
1 reconstructed barcode(s) found:

[1:Aztec]
Value: VintaSoft Barcode .NET SDK is the professional 1D & 2D barcode reader and barcode generator library for .NET Framework, .NET Core, WPF, WEB and Xamarin.Android.


Aztec barcodes do not require a quite zone around the barcode and this allows to place the barcodes tight to each other.


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