VintaSoft Barcode .NET SDK v10.0
Vintasoft.WpfBarcode.BarcodeInfo Namespace / PDF417StructuredAppendCharacter Class
Members Example




In This Topic
    PDF417StructuredAppendCharacter Class
    In This Topic
    Contains information about the PDF417 (Macro PDF417) and Micro PDF417 Structured Append non-data character.
    Object Model
    PDF417StructuredAppendCharacter Class
    Syntax
    'Declaration
     
    Public NotInheritable Class PDF417StructuredAppendCharacter 
       Inherits StructuredAppendCharacter
    'Usage
     
    Dim instance As PDF417StructuredAppendCharacter
    public sealed class PDF417StructuredAppendCharacter : StructuredAppendCharacter 
    public __gc __sealed class PDF417StructuredAppendCharacter : public StructuredAppendCharacter 
    public ref class PDF417StructuredAppendCharacter sealed : public StructuredAppendCharacter 
    Remarks
    A Structured Append character is used to indicate that the symbol is part of a Structured Append sequence.
    Structured Append provides a standard mechanism for creating a distributed representation of files too large to be represented by a single PDF417 or Micro PDF417 symbol. Using Structured Append, large files are split into several file segments and encoded into individual symbols. The Structured Append character defines the file ID, the concatenation sequence and optionally other information about the file.
    A Structured Append decoder uses the Structured Append character information to reconstruct the file correctly independently of symbol scanning order.

    For each related Structured Append symbol, the FileID field contains the same value. The file ID is a variable length field composed of triplets. Each triplet in the file ID can have a value between 000 and 899, effectively making the file ID a series of base 900 numbers.

    Structured Append character also contain a number of optional fields. Each optional field has field designator. Field designator defines field type and field encoding mode.
    Pre-defined field designators:
    • 0 - File Name, variable text (FileName).
    • 1 - Segment Count, fixed number 0..99999 (SymbolCount).
    • 2 - Time Stamp, fixed number, indicates the time stamp on the source file expressed as the elapsed time in seconds since 1970:01:01:00:00:00 GMT (TimeStamp).
    • 3 - Sender, variable text (Sender).
    • 4 - Addressee, variable text (Addressee).
    • 5 - FileSize, variable number (FileSize).
    • 6 - Checksum, fiexd number 0..65535 (Checksum).
    Field designator values greater than 6 are not currently defined. However, decoder and transmit any optional fields encountered with a field designator of 7 to 34 by treating the field data as variable text.
    Additional information about PDF417 Structured Append see in: ISO/IEC 24728, ISO/IEC 15438, Annex H.
    Example
    This example shows how to split data files into parts and reconstruct data files using PDF417 Structured Append character:
    Imports System.Collections.Generic   
    Imports System.Text   
    Imports System.Windows.Media.Imaging   
       
    Imports Vintasoft.WpfBarcode   
    Imports Vintasoft.WpfBarcode.BarcodeInfo   
       
    Class PDF417StructuredAppendCharacterExample   
    	''' <summary>   
    	''' The barcode type (PDF417, PDF417Compact or MicroPDF417).   
    	''' </summary>   
    	Shared _barcodeType As BarcodeType = BarcodeType.PDF417   
       
    	''' <summary>   
    	''' Splits 3 files into 9 parts (each file into 3 parts), creates barcodes from 9 parts,   
    	''' reorders barcodes, recognizes barcodes and restores content of 3 files.   
    	''' </summary>   
    	Public Shared Sub Test()   
    		' count of data files   
    		Dim fileCount As Integer = 3   
       
    		' count of parts in data file   
    		Dim symbolCount As Integer = 3   
       
    		' split data files to symbols   
    		Dim barcodeImages As New List(Of BitmapSource)()   
    		For i As Integer = 0 To fileCount - 1   
    			' file ID - series of triplets 000..899   
    			Dim fileId As String = (i + 1).ToString().PadLeft(3, "0"C)   
       
    			' split each data file to "symbolCount" symbols   
    			For j As Integer = 0 To symbolCount - 1   
    				' create structured append character   
    				Dim structureAppendCharacter As New PDF417StructuredAppendCharacter(j + 1, symbolCount, fileId)   
       
    				' add FileName information to the first symbol of data file   
    				If j = 0 Then   
    					structureAppendCharacter.FileName = String.Format("DataFile{0}", i + 1)   
    				End If   
       
    				' barcode value   
    				Dim symbolValue As String = String.Format("[Part {0} of file {1}]", j + 1, i + 1)   
       
    				' generate barcode image                   
    				barcodeImages.Add(GenerateBarcode(structureAppendCharacter, symbolValue))   
    			Next   
    		Next   
       
       
    		' resort barcode images   
    		barcodeImages.Reverse()   
    		barcodeImages.Reverse(0, barcodeImages.Count \ 2)   
    		barcodeImages.Reverse(barcodeImages.Count \ 3, (barcodeImages.Count \ 3) * 2)   
       
       
    		' recognize all barcodes and reconstruct data files   
    		Dim dataFiles As Dictionary(Of String, String) = ReconstructDataFiles(barcodeImages)   
       
    		' print reconstructed data files   
    		Console.WriteLine("Reconstructed data files:")   
    		For Each fileId As String In dataFiles.Keys   
    			Console.WriteLine(String.Format("File ID  : {0}", fileId))   
    			Console.WriteLine(String.Format("Data File: {0}", dataFiles(fileId)))   
    			Console.WriteLine()   
    		Next   
    	End Sub   
       
    	''' <summary>   
    	''' Generates the barcode image.   
    	''' </summary>   
    	''' <param name="structuredAppend">The structured append character.</param>   
    	''' <param name="barcodeValue">The barcode value.</param>   
    	Private Shared Function GenerateBarcode(structuredAppend As PDF417StructuredAppendCharacter, barcodeValue As String) As BitmapSource   
    		Dim writer As New BarcodeWriter()   
    		writer.Settings.Barcode = _barcodeType   
    		writer.Settings.ValueItems = New ValueItemBase() {structuredAppend, New TextValueItem(barcodeValue)}   
    		Return writer.GetBarcodeAsBitmapSource()   
    	End Function   
       
    	''' <summary>   
    	''' Reconstructs the data files.   
    	''' </summary>   
    	''' <param name="barcodeImages">The barcode images.</param>   
    	''' <returns>Dictonary (fileId -> DataFile) that contaions recontructed data files.</returns>   
    	Private Shared Function ReconstructDataFiles(barcodeImages As List(Of BitmapSource)) As Dictionary(Of String, String)   
    		' create barcode reader   
    		Using reader As New BarcodeReader()   
    			reader.Settings.ScanBarcodeTypes = _barcodeType   
       
    			' Dictionary: FileId -> (symbolPosition -> barcodeValue)   
    			Dim recognizeBarcodes As New Dictionary(Of String, Dictionary(Of Integer, String))()   
       
    			' for each barcode image   
    			For i As Integer = 0 To barcodeImages.Count - 1   
    				' recognize barcode   
    				Console.WriteLine(String.Format("Recognize image {0}...", i + 1))   
    				Dim info As IBarcodeInfo = reader.ReadBarcodes(barcodeImages(i))(0)   
    				Dim valueItems As ValueItemBase() = info.ValueItems   
       
    				' structured append character   
    				Dim saCharacter As PDF417StructuredAppendCharacter = DirectCast(valueItems(0), PDF417StructuredAppendCharacter)   
       
    				' barcode value   
    				info.ShowNonDataFlagsInValue = False   
    				Dim barcodeValue As String = info.Value   
       
    				' show information about recognized barcode   
    				Console.WriteLine(String.Format("  Value   : {0}", barcodeValue))   
    				Console.WriteLine(String.Format("  Symbol  : {0} of {1}", saCharacter.SymbolPosition, saCharacter.SymbolCount))   
    				Console.WriteLine(String.Format("  File ID : {0}", saCharacter.FileID))   
    				If saCharacter.FileName IsNot Nothing Then   
    					Console.WriteLine(String.Format("  FileName: {0}", saCharacter.FileName))   
    				End If   
    				Console.WriteLine()   
       
    				' add barcode value to recognizeBarcodes table   
    				Dim positionsToDataFileParts As Dictionary(Of Integer, String)   
    				If Not recognizeBarcodes.TryGetValue(saCharacter.FileID, positionsToDataFileParts) Then   
    					positionsToDataFileParts = New Dictionary(Of Integer, String)()   
    					recognizeBarcodes(saCharacter.FileID) = positionsToDataFileParts   
    				End If   
    				positionsToDataFileParts.Add(saCharacter.SymbolPosition, barcodeValue)   
    			Next   
       
    			' reconstruct data files   
    			Dim dataFiles As New Dictionary(Of String, String)()   
    			For Each fileId As String In recognizeBarcodes.Keys   
    				Dim positionsToDataFileParts As Dictionary(Of Integer, String) = recognizeBarcodes(fileId)   
       
    				' symbol positions   
    				Dim positions As Integer() = New Integer(positionsToDataFileParts.Count - 1) {}   
    				positionsToDataFileParts.Keys.CopyTo(positions, 0)   
       
    				' data file parts   
    				Dim dataFileParts As String() = New String(positionsToDataFileParts.Count - 1) {}   
    				positionsToDataFileParts.Values.CopyTo(dataFileParts, 0)   
       
    				' sort data file parts by symbol posiotions   
    				Array.Sort(positions, dataFileParts)   
       
    				' merge data file parts   
    				Dim dataFile As New StringBuilder()   
    				For Each dataFilePart As String In dataFileParts   
    					dataFile.Append(dataFilePart)   
    				Next   
    				dataFiles(fileId) = dataFile.ToString()   
    			Next   
       
    			Return dataFiles   
    		End Using   
    	End Function   
    End Class   
       
    ' This code example produces the following output:    
    '   
    'Recognize image 1...   
    '  Value   : [Part 3 of file 2]   
    '  Symbol  : 3 of 3   
    '  File ID : 002   
    '   
    'Recognize image 2...   
    '  Value   : [Part 1 of file 3]   
    '  Symbol  : 1 of 3   
    '  File ID : 003   
    '  FileName: DataFile3   
    '   
    'Recognize image 3...   
    '  Value   : [Part 2 of file 3]   
    '  Symbol  : 2 of 3   
    '  File ID : 003   
    '   
    'Recognize image 4...   
    '  Value   : [Part 1 of file 1]   
    '  Symbol  : 1 of 3   
    '  File ID : 001   
    '  FileName: DataFile1   
    '   
    'Recognize image 5...   
    '  Value   : [Part 2 of file 1]   
    '  Symbol  : 2 of 3   
    '  File ID : 001   
    '   
    'Recognize image 6...   
    '  Value   : [Part 3 of file 1]   
    '  Symbol  : 3 of 3   
    '  File ID : 001   
    '   
    'Recognize image 7...   
    '  Value   : [Part 1 of file 2]   
    '  Symbol  : 1 of 3   
    '  File ID : 002   
    '  FileName: DataFile2   
    '   
    'Recognize image 8...   
    '  Value   : [Part 2 of file 2]   
    '  Symbol  : 2 of 3   
    '  File ID : 002   
    '   
    'Recognize image 9...   
    '  Value   : [Part 3 of file 3]   
    '  Symbol  : 3 of 3   
    '  File ID : 003   
    '   
    'Reconstructed data files:   
    'File ID  : 002   
    'Data File: [Part 1 of file 2][Part 2 of file 2][Part 3 of file 2]   
    '   
    'File ID  : 003   
    'Data File: [Part 1 of file 3][Part 2 of file 3][Part 3 of file 3]   
    '   
    'File ID  : 001   
    'Data File: [Part 1 of file 1][Part 2 of file 1][Part 3 of file 1]   
    '
    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Windows.Media.Imaging;
                
    using Vintasoft.WpfBarcode;
    using Vintasoft.WpfBarcode.BarcodeInfo;
                
    class PDF417StructuredAppendCharacterExample
    {
        /// <summary>
        /// The barcode type (PDF417, PDF417Compact or MicroPDF417).
        /// </summary>
        static BarcodeType _barcodeType = BarcodeType.PDF417;
                
        /// <summary>
        /// Splits 3 files into 9 parts (each file into 3 parts), creates barcodes from 9 parts,
        /// reorders barcodes, recognizes barcodes and restores content of 3 files.
        /// </summary>
        public static void Test()
        {
            // count of data files
            int fileCount = 3;
                
            // count of parts in data file
            int symbolCount = 3;
                
            // split data files to symbols
            List<BitmapSource> barcodeImages = new List<BitmapSource>();
            for (int i = 0; i < fileCount; i++)
            {
                // file ID - series of triplets 000..899
                string fileId = (i + 1).ToString().PadLeft(3, '0');
                
                // split each data file to "symbolCount" symbols
                for (int j = 0; j < symbolCount; j++)
                {
                    // create structured append character
                    PDF417StructuredAppendCharacter structureAppendCharacter =
                        new PDF417StructuredAppendCharacter(j + 1, symbolCount, fileId);
                    
                    // add FileName information to the first symbol of data file
                    if (j == 0)
                        structureAppendCharacter.FileName = string.Format("DataFile{0}", i + 1);
                    
                    // barcode value
                    string symbolValue = string.Format("[Part {0} of file {1}]", j + 1, i + 1);
                
                    // generate barcode image                
                    barcodeImages.Add(GenerateBarcode(structureAppendCharacter, symbolValue));
                }
            }
                
                
            // resort barcode images
            barcodeImages.Reverse();
            barcodeImages.Reverse(0, barcodeImages.Count / 2);
            barcodeImages.Reverse(barcodeImages.Count / 3, (barcodeImages.Count / 3) * 2);
                
                
            // recognize all barcodes and reconstruct data files
            Dictionary<string, string> dataFiles = ReconstructDataFiles(barcodeImages);
                
            // print reconstructed data files
            Console.WriteLine("Reconstructed data files:");
            foreach (string fileId in dataFiles.Keys)
            {
                Console.WriteLine(string.Format("File ID  : {0}", fileId));
                Console.WriteLine(string.Format("Data File: {0}", dataFiles[fileId]));
                Console.WriteLine();
            }
        }
                
        /// <summary>
        /// Generates the barcode image.
        /// </summary>
        /// <param name="structuredAppend">The structured append character.</param>
        /// <param name="barcodeValue">The barcode value.</param>
        private static BitmapSource GenerateBarcode(
            PDF417StructuredAppendCharacter structuredAppend,
            string barcodeValue)
        {
            BarcodeWriter writer = new BarcodeWriter();
            writer.Settings.Barcode = _barcodeType;
            writer.Settings.ValueItems = new ValueItemBase[] { 
                structuredAppend, new TextValueItem(barcodeValue) };
            return writer.GetBarcodeAsBitmapSource();
        }
                
        /// <summary>
        /// Reconstructs the data files.
        /// </summary>
        /// <param name="barcodeImages">The barcode images.</param>
        /// <returns>Dictonary (fileId -> DataFile) that contaions recontructed data files.</returns>
        private static Dictionary<string, string> ReconstructDataFiles(List<BitmapSource> barcodeImages)
        {
            // create barcode reader
            using (BarcodeReader reader = new BarcodeReader())
            {
                reader.Settings.ScanBarcodeTypes = _barcodeType;
                
                // Dictionary: FileId -> (symbolPosition -> barcodeValue)
                Dictionary<string, Dictionary<int, string>> recognizeBarcodes =
                    new Dictionary<string, Dictionary<int, string>>();
                
                // for each barcode image
                for (int i = 0; i < barcodeImages.Count; i++)
                {
                    // recognize barcode
                    Console.WriteLine(string.Format("Recognize image {0}...", i + 1));
                    IBarcodeInfo info = reader.ReadBarcodes(barcodeImages[i])[0];
                    ValueItemBase[] valueItems = info.ValueItems;
                
                    // structured append character
                    PDF417StructuredAppendCharacter saCharacter = (PDF417StructuredAppendCharacter)valueItems[0];
                
                    // barcode value
                    info.ShowNonDataFlagsInValue = false;
                    string barcodeValue = info.Value;
                
                    // show information about recognized barcode
                    Console.WriteLine(string.Format("  Value   : {0}", barcodeValue));
                    Console.WriteLine(string.Format("  Symbol  : {0} of {1}", saCharacter.SymbolPosition, saCharacter.SymbolCount));
                    Console.WriteLine(string.Format("  File ID : {0}", saCharacter.FileID));
                    if (saCharacter.FileName != null)
                        Console.WriteLine(string.Format("  FileName: {0}", saCharacter.FileName));
                    Console.WriteLine();
                
                    // add barcode value to recognizeBarcodes table
                    Dictionary<int, string> positionsToDataFileParts;
                    if (!recognizeBarcodes.TryGetValue(saCharacter.FileID, out positionsToDataFileParts))
                    {
                        positionsToDataFileParts = new Dictionary<int, string>();
                        recognizeBarcodes[saCharacter.FileID] = positionsToDataFileParts;
                    }
                    positionsToDataFileParts.Add(saCharacter.SymbolPosition, barcodeValue);
                }
                
                // reconstruct data files
                Dictionary<string, string> dataFiles = new Dictionary<string, string>();
                foreach (string fileId in recognizeBarcodes.Keys)
                {
                    Dictionary<int, string> positionsToDataFileParts = recognizeBarcodes[fileId];
                
                    // symbol positions
                    int[] positions = new int[positionsToDataFileParts.Count];
                    positionsToDataFileParts.Keys.CopyTo(positions, 0);
                
                    // data file parts
                    string[] dataFileParts = new string[positionsToDataFileParts.Count];
                    positionsToDataFileParts.Values.CopyTo(dataFileParts, 0);
                
                    // sort data file parts by symbol posiotions
                    Array.Sort(positions, dataFileParts);
                
                    // merge data file parts
                    StringBuilder dataFile = new StringBuilder();
                    foreach (string dataFilePart in dataFileParts)
                        dataFile.Append(dataFilePart);
                    dataFiles[fileId] = dataFile.ToString();
                }
                
                return dataFiles;
            }
        }
    }
                
    /* This code example produces the following output: 
                
    Recognize image 1...
      Value   : [Part 3 of file 2]
      Symbol  : 3 of 3
      File ID : 002
                
    Recognize image 2...
      Value   : [Part 1 of file 3]
      Symbol  : 1 of 3
      File ID : 003
      FileName: DataFile3
                
    Recognize image 3...
      Value   : [Part 2 of file 3]
      Symbol  : 2 of 3
      File ID : 003
                
    Recognize image 4...
      Value   : [Part 1 of file 1]
      Symbol  : 1 of 3
      File ID : 001
      FileName: DataFile1
                
    Recognize image 5...
      Value   : [Part 2 of file 1]
      Symbol  : 2 of 3
      File ID : 001
                
    Recognize image 6...
      Value   : [Part 3 of file 1]
      Symbol  : 3 of 3
      File ID : 001
                
    Recognize image 7...
      Value   : [Part 1 of file 2]
      Symbol  : 1 of 3
      File ID : 002
      FileName: DataFile2
                
    Recognize image 8...
      Value   : [Part 2 of file 2]
      Symbol  : 2 of 3
      File ID : 002
                
    Recognize image 9...
      Value   : [Part 3 of file 3]
      Symbol  : 3 of 3
      File ID : 003
                
    Reconstructed data files:
    File ID  : 002
    Data File: [Part 1 of file 2][Part 2 of file 2][Part 3 of file 2]
                
    File ID  : 003
    Data File: [Part 1 of file 3][Part 2 of file 3][Part 3 of file 3]
                
    File ID  : 001
    Data File: [Part 1 of file 1][Part 2 of file 1][Part 3 of file 1]
    */
    Inheritance Hierarchy

    System.Object
       Vintasoft.WpfBarcode.BarcodeInfo.ValueItemBase
          Vintasoft.WpfBarcode.BarcodeInfo.NonDataFlagValueItem
             Vintasoft.WpfBarcode.BarcodeInfo.StructuredAppendCharacter
                Vintasoft.WpfBarcode.BarcodeInfo.PDF417StructuredAppendCharacter

    Requirements

    Target Platforms: Windows 8, Windows 7, Windows Vista, Windows XP, Windows Server 2012, Windows Server 2008, Windows Server 2003

    See Also