ReadBarcodes(RasterImage,LogicalRectangle,Int32,BarcodeSymbology[],BarcodeReadOptions[]) Method

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Forms 
Imports Leadtools.Barcode 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
 
' 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 name containing the barcodes 
   Public ImageFileName As String 
 
   ' Image containing the barcodes 
   Public Image As RasterImage 
 
   ' 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 AutoResetEvent 
End Class 
 
<TestMethod(), Asynchronous()> 
Public Sub BarcodeReaderReadBarcodeExample6() 
   BarcodeReader_ReadBarcodeExample6() 
   EnqueueTestComplete() 
End Sub 
 
Public Sub BarcodeReader_ReadBarcodeExample6() 
   Dim images As RasterImage() = New RasterImage(1) {} 
   Dim originalImageFileName As String = "Barcode1.tif" 
   Dim rotatedImageFileName As String = "Barcode1_Rotated90.tif" 
   Dim imageFileNames As String() = New String() {originalImageFileName, rotatedImageFileName} 
 
   Using outputStream As SampleImageStream = New SampleImageStream("Barcode1_Rotated90.tif") 
      images(0) = SampleImage.Get(SampleImageNames.Barcode1_tif).Clone() 
      images(1) = SampleImage.Get(SampleImageNames.Barcode1_tif).Clone() 
      RotateImage(images(1)) 
 
      ' Create a Barcode engine 
      Dim engine As BarcodeEngine = 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 AutoResetEvent() = New AutoResetEvent(1) {} 
 
      ' Create the thread data objects 
      Dim threadsData As MyThreadData() = New MyThreadData(1) {} 
      Dim i As Integer = 0 
      Do While i < threadsData.Length 
         finishedEvents(i) = New AutoResetEvent(False) 
 
         threadsData(i) = New MyThreadData() 
         threadsData(i).BarcodeReaderInstance = reader 
         threadsData(i).ReadOptions = Nothing 
         threadsData(i).FinishedEvent = finishedEvents(i) 
         i += 1 
      Loop 
 
      ' 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 List(Of BarcodeData) = New List(Of BarcodeData)() 
 
      ' Now loop through all the images and try to read the barcodes with both threads at the same time 
      Dim index As Integer = 0 
      For Each image As RasterImage In images 
         Console.WriteLine("Reading barcodes from {0}", imageFileNames(index)) 
 
         For i = 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).Image = image 
            threadsData(i).ImageFileName = imageFileNames(index) 
            ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf ReadBarcodesInThread), threadsData(i)) 
         Next i 
 
         ' Wait till all the threads finishes 
         WaitHandle.WaitAll(finishedEvents) 
 
         ' Add the barcodes found to our list 
         For i = 0 To 1 
            If Not threadsData(i).Error Is Nothing Then 
               Console.WriteLine("{0} had error {1}", threadsData(i).Name, threadsData(i).Error) 
            ElseIf Not threadsData(i).Barcodes Is Nothing Then 
               totalBarcodes.AddRange(threadsData(i).Barcodes) 
            End If 
         Next i 
 
         index += 1 
      Next image 
 
      ' We are done, show the total number of barcodes read 
      Console.WriteLine("Done. Total barcodes read: {0}", totalBarcodes.Count) 
   End Using 
End Sub 
 
Private Shared Sub ReadBarcodesInThread(ByVal state As Object) 
   Dim threadData As MyThreadData = TryCast(state, MyThreadData) 
 
   Console.WriteLine("{0} is reading the barcodes", threadData.Name) 
 
   Try 
      ' Load the image 
      Dim codecs As RasterCodecs = 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, LogicalRectangle.Empty, 0, Nothing, threadData.ReadOptions) 
      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 Sub RotateImage(ByVal image As RasterImage) 
   ' Create a 90 degrees rotated version of Barcode1.tif 
 
   Dim codecs As RasterCodecs = New RasterCodecs() 
 
   Dim rotate As RotateCommand = New RotateCommand(90 * 100, RotateCommandFlags.Resize, RasterColor.FromKnownColor(RasterKnownColor.White)) 
   rotate.Run(image) 
End Sub 
 
Private Shared Function GetVerticalReadBarcodeOptions(ByVal 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