在 .NET 中使用 XFA 压缩生成二维条码

如果使用扁平（ZIP）压缩方式压缩条形码数据（例如序列号列表、XML 数据、URL 等），则可以减小条形码数据的大小。
在以下情况下，减小条形码数据的大小可能是必要的：

• 减小条形码的物理尺寸；
• 保持条形码尺寸不变，但增大条形码矩阵的单元格尺寸，以降低扫描或拍摄的质量要求；
• 保持条形码尺寸不变，但提高纠错级别，以增强条形码的抗损坏能力；
• 在保持条形码原始物理尺寸的同时，编码数倍的数据量。

VintaSoft Barcode .NET SDK 提供两种压缩二维条码数据的方法。

方法 1： 自行压缩数据并生成包含压缩二进制数据的二维条形码。这是可行的，因为所有二维条形码都允许您存储二进制数据（有关详细信息，请参阅 BinaryValueItem 类）。

方法 2： 根据 XML 表单架构 (XFA) 规范生成二维条形码。在这种情况下，条形码数据将使用"DEFLATE 压缩数据格式"(RFC1951) 压缩算法进行压缩。


本文将展示如何根据 XML 表单架构 (XFA) 规范生成二维条形码。

VintaSoft Barcode .NET SDK 提供一些类，可以轻松创建和识别使用 XFA 压缩数据的条码：

• XFA Compressed Aztec
• XFA Compressed DataMatrix
• XFA Compressed PDF417
• XFA Compressed QR

以下是 C# 代码，可用于创建符合 XFA 规范的压缩数据的 Aztec 条形码：

/// <summary>
/// Generates Aztec barcode with XFA compression.
/// </summary>
public void GenerateAztecBarcodeWithXfaCompression()
{
    string barcodeText =
        "https://www.vintasoft.com/vsbarcode-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsimaging-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsannotation-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vspdf-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjbig2-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjpeg2000-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdoccleanup-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsocr-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdicom-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsformsprocessing-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsoffice-dotnet-index.html";

    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // create the XFA compressed Aztec barcode symbology
    Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedAztecBarcodeSymbology xfaCompressedAztecBarcodeSymbology =
        new Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedAztecBarcodeSymbology();
    // encode barcode text using XFA compressed Aztec barcode symbology
    xfaCompressedAztecBarcodeSymbology.Encode(barcodeText, barcodeWriter.Settings);

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

以下是包含符合 XFA 规范的压缩 URL 列表的 Aztec 条形码图像：

以下是包含未压缩文本形式的 URL 列表的 Aztec 条形码图像：


以下是 C# 代码，可用于创建符合 XFA 规范的压缩数据 DataMatrix 条形码：

/// <summary>
/// Generates DataMatrix barcode with XFA compression.
/// </summary>
public void GenerateDataMatrixBarcodeWithXfaCompression()
{
    string barcodeText =
        "https://www.vintasoft.com/vsbarcode-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsimaging-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsannotation-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vspdf-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjbig2-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjpeg2000-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdoccleanup-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsocr-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdicom-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsformsprocessing-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsoffice-dotnet-index.html";

    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // create the XFA compressed DataMatrix barcode symbology
    Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedDataMatrixBarcodeSymbology xfaCompressedDataMatrixBarcodeSymbology =
        new Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedDataMatrixBarcodeSymbology();
    // encode barcode text using XFA compressed DataMatrix barcode symbology
    xfaCompressedDataMatrixBarcodeSymbology.Encode(barcodeText, barcodeWriter.Settings);

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

以下是 DataMatrix 条形码的图像，其中包含符合 XFA 规范的压缩 URL 列表：

以下是 DataMatrix 条形码的图像，其中包含未压缩文本形式的 URL 列表：


以下是 C# 代码，可用于创建符合 XFA 规范的压缩数据 PDF417 条形码：

/// <summary>
/// Generates PDF417 barcode with XFA compression.
/// </summary>
public void GeneratePdf417BarcodeWithXfaCompression()
{
    string barcodeText =
        "https://www.vintasoft.com/vsbarcode-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsimaging-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsannotation-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vspdf-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjbig2-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjpeg2000-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdoccleanup-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsocr-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdicom-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsformsprocessing-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsoffice-dotnet-index.html";

    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // create the XFA compressed PDF417 barcode symbology
    Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedPDF417BarcodeSymbology xfaCompressedPdf417BarcodeSymbology =
        new Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedPDF417BarcodeSymbology();
    // encode barcode text using XFA compressed PDF417 barcode symbology
    xfaCompressedPdf417BarcodeSymbology.Encode(barcodeText, barcodeWriter.Settings);

    // get barcode as image
    using (System.Drawing.Image barcodeImage = barcodeWriter.GetBarcodeAsBitmap())
    {
        // save the barcode image to a file
        barcodeImage.Save("pdf417-barcode-with-xfa-compression.png");
    }
}

此处为 PDF417 条形码图像，其中包含符合 XFA 规范的压缩 URL 列表：

此处为 PDF417 条形码图像，其中包含未压缩文本形式的 URL 列表：


以下 C# 代码可用于创建符合 XFA 规范的压缩数据 QR 码：

/// <summary>
/// Generates QR barcode with XFA compression.
/// </summary>
public void GenerateQrCodeBarcodeWithXfaCompression()
{
    string barcodeText =
        "https://www.vintasoft.com/vsbarcode-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vstwain-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsimaging-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsannotation-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vspdf-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjbig2-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsjpeg2000-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdoccleanup-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsocr-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsdicom-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsformsprocessing-dotnet-index.html" + System.Environment.NewLine +
        "https://www.vintasoft.com/vsoffice-dotnet-index.html";

    // create the barcode writer
    Vintasoft.Barcode.BarcodeWriter barcodeWriter = new Vintasoft.Barcode.BarcodeWriter();

    // create the XFA compressed QR barcode symbology
    Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedQRCodeBarcodeSymbology xfaCompressedQrCodeBarcodeSymbology =
        new Vintasoft.Barcode.SymbologySubsets.XFACompressed.XFACompressedQRCodeBarcodeSymbology();
    // encode barcode text using XFA compressed QR barcode symbology
    xfaCompressedQrCodeBarcodeSymbology.Encode(barcodeText, barcodeWriter.Settings);

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

此处为 QR 条形码图像，其中包含符合 XFA 规范的压缩 URL 列表：

此处为 QR 条形码图像，其中包含未压缩文本形式的 URL 列表：



以下 C# 代码可用于识别二维条形码按照 XFA 规范生成的条形码：

/// <summary>
/// Recognizes 2D barcode with XFA compressed data.
/// </summary>
/// <param name="barcodeImageFile">A path to a barcode image file.</param>
public void Recognize2DBarcodeWithXfaCompressedData(string barcodeImageFile)
{
    // create barcode reader
    using (Vintasoft.Barcode.BarcodeReader reader = new Vintasoft.Barcode.BarcodeReader())
    {
        // specify that reader must search for XFA compressed Aztec barcodes
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.XFACompressedAztec);
        // specify that reader must search for XFA compressed DataMatrix barcodes
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.XFACompressedDataMatrix);
        // specify that reader must search for XFA compressed PDF417 barcodes
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.XFACompressedPDF417);
        // specify that reader must search for XFA compressed QR barcodes
        reader.Settings.ScanBarcodeSubsets.Add(Vintasoft.Barcode.SymbologySubsets.BarcodeSymbologySubsets.XFACompressedQRCode);

        // 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(barcodeImageFile);

        // 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();
            }
        }
    }
    System.Console.WriteLine();
    System.Console.WriteLine();
}

需要注意的是，如果数据冗余较少或数据流过短，扁平压缩（ZIP）可能会增加数据量。