ReadBarcodes(RasterImage,LeadRect,int,BarcodeSymbology[],BarcodeReadOptions[]) Method

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Barcode 
Imports Leadtools.ImageProcessing 
 
' This class holds the data we will pass to each thread 
 
Public Class MyThreadData 
   ' This worker thread name 
   Public Name As String 
 
   ' Barcode reader instance 
   Public BarcodeReaderInstance As BarcodeReader 
 
   ' Array of options to use 
   Public ReadOptions As BarcodeReadOptions() 
 
   ' Image file containing the barcodes 
   Public ImageFileName As String 
 
   ' This will hold the barcodes found 
   Public Barcodes As BarcodeData() 
 
   ' In case of errors 
   Public [Error] As Exception 
 
   ' Event to notify when the thread is finished 
   Public FinishedEvent As ManualResetEvent 
End Class 
 
Public Sub BarcodeReader_ReadBarcodeExample6() 
   Dim imageFileNames As String() = PrepareImages() 
 
   ' Create a Barcode engine 
   Dim engine As New BarcodeEngine() 
 
   ' Get the Barcode reader instance 
   Dim reader As BarcodeReader = engine.Reader 
 
   ' Get a version of all read options that support rotated barcodes 
   Dim verticalBarcodeReadOptions As BarcodeReadOptions() = GetVerticalReadBarcodeOptions(reader) 
 
   ' Synchronization events 
   Dim finishedEvents As ManualResetEvent() = New ManualResetEvent(1) {} 
 
   ' Create the thread data objects 
   Dim threadsData As MyThreadData() = New MyThreadData(1) {} 
   For i As Integer = 0 To threadsData.Length - 1 
      finishedEvents(i) = New ManualResetEvent(False) 
 
      threadsData(i) = New MyThreadData() 
      threadsData(i).BarcodeReaderInstance = reader 
      threadsData(i).ReadOptions = Nothing 
      threadsData(i).FinishedEvent = finishedEvents(i) 
   Next 
 
   ' Setup the read options for the two threads 
   threadsData(0).Name = "Read Default Options Thread" 
   threadsData(0).ReadOptions = Nothing 
   ' Default, or horizontal 
   threadsData(1).Name = "Read Vertical Barcodes Thread" 
   threadsData(1).ReadOptions = verticalBarcodeReadOptions 
 
   Dim totalBarcodes As New List(Of BarcodeData)() 
 
   ' Now loop through all the images and try to read the barcodes with both threads at the same time 
   For Each imageFileName As String In imageFileNames 
      Console.WriteLine("Reading barcodes from {0}", imageFileName) 
 
      For i As Integer = 0 To 1 
         ' Clear the previous results (if any), set up the file name and run 
         threadsData(i).Barcodes = Nothing 
         threadsData(i).[Error] = Nothing 
         threadsData(i).ImageFileName = imageFileName 
         ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf ReadBarcodesInThread), threadsData(i)) 
      Next 
 
      ' Wait till all the threads finishes 
      For Each waitHandle As ManualResetEvent In finishedEvents 
         waitHandle.WaitOne() 
      Next 
 
      ' Add the barcodes found to our list 
      For i As Integer = 0 To 1 
         If threadsData(i).[Error] IsNot Nothing Then 
            Console.WriteLine("{0} had error {1}", threadsData(i).Name, threadsData(i).[Error]) 
         ElseIf threadsData(i).Barcodes IsNot Nothing Then 
            totalBarcodes.AddRange(threadsData(i).Barcodes) 
         End If 
      Next 
   Next 
 
   ' We are done, show the total number of barcodes read 
   Console.WriteLine("Done. Total barcodes read: {0}", totalBarcodes.Count) 
End Sub 
 
Private Shared Sub ReadBarcodesInThread(state As Object) 
   Dim threadData As MyThreadData = TryCast(state, MyThreadData) 
 
   Console.WriteLine("{0} is reading the barcodes", threadData.Name) 
 
   Try 
      ' Load the image 
      Using codecs As New RasterCodecs() 
         Using image As RasterImage = codecs.Load(threadData.ImageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1) 
            ' Read the barcodes using our options 
            threadData.Barcodes = threadData.BarcodeReaderInstance.ReadBarcodes(image, LeadRect.Empty, 0, Nothing, threadData.ReadOptions) 
         End Using 
      End Using 
 
      Console.WriteLine("{0} has read {1} barcodes", threadData.Name, threadData.Barcodes.Length) 
   Catch ex As Exception 
      ' Return the error to main 
      threadData.[Error] = ex 
   Finally 
      ' Tell main we are done 
      threadData.FinishedEvent.[Set]() 
   End Try 
End Sub 
 
Private Shared Function PrepareImages() As String() 
   ' Create a 90 degrees rotated version of Barcode1.tif 
 
   Dim originalImageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1.tif") 
   Dim rotatedImageFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "Barcode1_Rotated90.tif") 
 
   Using codecs As New RasterCodecs() 
      Using image As RasterImage = codecs.Load(originalImageFileName, 0, CodecsLoadByteOrder.BgrOrGray, 1, 1) 
         Dim rotate As New RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White)) 
         rotate.Run(image) 
 
         codecs.Save(image, rotatedImageFileName, RasterImageFormat.CcittGroup4, 1) 
      End Using 
   End Using 
 
   Return New String() {originalImageFileName, rotatedImageFileName} 
End Function 
 
Private Shared Function GetVerticalReadBarcodeOptions(reader As BarcodeReader) As BarcodeReadOptions() 
   ' By default, the options read horizontal barcodes only, create an array of options capable of reading vertical barcodes 
 
   ' Notice, we cloned the default options in reader so we will not change the original options 
 
   Dim oneDReadOptions As OneDBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.UPCA).Clone(), OneDBarcodeReadOptions) 
   oneDReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim fourStateReadOptions As FourStateBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.USPS4State).Clone(), FourStateBarcodeReadOptions) 
   fourStateReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim postNetPlanetReadOptions As PostNetPlanetBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.PostNet).Clone(), PostNetPlanetBarcodeReadOptions) 
   postNetPlanetReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim gs1StackedReadOptions As GS1DatabarStackedBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.GS1DatabarStacked).Clone(), GS1DatabarStackedBarcodeReadOptions) 
   gs1StackedReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim patchCodeReadOptions As PatchCodeBarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.PatchCode).Clone(), PatchCodeBarcodeReadOptions) 
   patchCodeReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim pdf417ReadOptions As PDF417BarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.PDF417).Clone(), PDF417BarcodeReadOptions) 
   pdf417ReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   Dim microPdf417ReadOptions As MicroPDF417BarcodeReadOptions = TryCast(reader.GetDefaultOptions(BarcodeSymbology.MicroPDF417).Clone(), MicroPDF417BarcodeReadOptions) 
   microPdf417ReadOptions.SearchDirection = BarcodeSearchDirection.Vertical 
 
   ' Even though this array will not contain all options, it should be enough to read all barcodes, since the version of ReadBarcodes we will use 
   ' will use the default options if an overriden is not passed 
   Dim readOptions As BarcodeReadOptions() = {oneDReadOptions, fourStateReadOptions, postNetPlanetReadOptions, gs1StackedReadOptions, patchCodeReadOptions, pdf417ReadOptions, 
      microPdf417ReadOptions} 
 
   Return readOptions 
End Function 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class