Imports System.ComponentModel
Imports System.Drawing
Imports System.Media
Imports System.Reflection
Imports System.Text
Imports System.Threading
Imports System.Windows.Forms
Imports Bytescout.BarCodeReader
Imports TouchlessLib

Public Class MainForm

    ' Scan delay, ms.
    Const SCAN_DELAY As Integer = 1500 ' scan barcodes every 1.5 sec

    ' Touchless SDK library manager (to use it you should have TouchlessLib.dll referenced and WebCamLib.dll in the build output directory)
    Dim ReadOnly _touchlessLibManager As TouchlessMgr

    ' Background thread for barcode scanning
    Dim ReadOnly _backgroundWorker As New BackgroundWorker
    ' Synchronization event
    Dim ReadOnly _synchronizationEvent As New AutoResetEvent(False)

    ' Form constructor
    Public Sub New()

        InitializeComponent()

        ' Create Touchless library manager
        _touchlessLibManager = New TouchlessMgr()

        ' Setup background worker
        _backgroundWorker.WorkerSupportsCancellation = True
        AddHandler _backgroundWorker.DoWork, AddressOf BackgroundWorker_DoWork
        AddHandler _backgroundWorker.RunWorkerCompleted, AddressOf BackgroundWorker_RunWorkerCompleted

    End Sub

    ' On form loading 
    Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        ' Fill devices combobox with available video cameras
        For Each camera As Camera In _touchlessLibManager.Cameras
            cmbCamera.Items.Add(camera)
        Next

        ' Select the first available camera. See also cmbCamera_SelectedIndexChanged event handler.
        If _touchlessLibManager.Cameras.Count > 0 Then
            cmbCamera.SelectedItem = _touchlessLibManager.Cameras(0)
        Else
            MessageBox.Show("No video camera available. Please connect the camera.")
        End If

        ' Populate barcode types combobox
        PopulateBarcodeTypesCombobox()
        ' Select some default barcode type
        cmbBarcodeType.SelectedItem = "QRCode"

    End Sub

    Private Sub PopulateBarcodeTypesCombobox()

        cmbBarcodeType.Items.Clear()

        For Each propertyInfo As PropertyInfo In GetType(BarcodeTypeSelector).GetProperties()
            cmbBarcodeType.Items.Add(propertyInfo.Name)
        Next

    End Sub

    ' On camera selected
    Private Sub cmbCamera_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbCamera.SelectedIndexChanged

        If _touchlessLibManager.CurrentCamera IsNot Nothing Then
            RemoveHandler _touchlessLibManager.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured
        End If

        If cmbCamera.SelectedIndex <> -1 Then

            Dim camera As Camera = _touchlessLibManager.Cameras(cmbCamera.SelectedIndex)

            If camera IsNot Nothing Then
                ' Set camera output image dimensions
                camera.CaptureWidth = Integer.Parse(tbCameraWidth.Text)
                camera.CaptureHeight = Integer.Parse(tbCameraHeight.Text)

                AddHandler camera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured

                ' Select the camera
                _touchlessLibManager.CurrentCamera = camera

            End If

        End If

    End Sub

    Private Sub btnUpdateCameraImageDimensions_Click(sender As Object, e As EventArgs) Handles btnUpdateCameraImageDimensions.Click

        If _touchlessLibManager.CurrentCamera IsNot Nothing Then

            ' Update camera's output image dimensions
            _touchlessLibManager.CurrentCamera.CaptureWidth = Integer.Parse(tbCameraWidth.Text)
            _touchlessLibManager.CurrentCamera.CaptureHeight = Integer.Parse(tbCameraHeight.Text)

        End If

    End Sub

    Private Sub StartDecoding()

        If cmbCamera.SelectedIndex = -1 Then
            Return
        End If

        ' Clear the output text box
        rtbFoundBarcodes.Clear()

        ' Check if we have camera selected
        If cmbCamera.SelectedIndex <> -1 Then

            ' Start the decoding in the background thread
            Dim barcodeTypesToFind As BarcodeTypeSelector = GetBarcodeTypeFromCombobox()
            _backgroundWorker.RunWorkerAsync(barcodeTypesToFind)

            UpdateControls(True)
        Else
            MessageBox.Show("Please select the camera first!")
        End If

    End Sub

    Private Sub StopDecoding()

        _backgroundWorker.CancelAsync()

        ' Wait until BackgroundWorker finished
        If _backgroundWorker.IsBusy Then
            _synchronizationEvent.WaitOne()
        End If

        UpdateControls(False)

    End Sub

    Private Sub UpdateControls(started As Boolean)

        If started Then
            btnStart.Enabled = False
            btnStop.Enabled = True
            cmbBarcodeType.Enabled = False
            cmbCamera.Enabled = False
            tbCameraHeight.Enabled = False
            tbCameraWidth.Enabled = False
            btnUpdateCameraImageDimensions.Enabled = False
            cbStopOnFirstBarcode.Enabled = False
            lblScanning.Visible = True
            lblScanning.Text = "Scanning..."
        Else
            btnStart.Enabled = True
            btnStop.Enabled = False
            cmbBarcodeType.Enabled = True
            cmbCamera.Enabled = True
            cbStopOnFirstBarcode.Enabled = True
            tbCameraHeight.Enabled = True
            tbCameraWidth.Enabled = True
            btnUpdateCameraImageDimensions.Enabled = True
            lblScanning.Visible = True
        End If

    End Sub

    Private Sub CurrentCamera_OnImageCaptured(sender As Object, e As CameraEventArgs)

        pictureBoxPreview.Image = e.Image

    End Sub

    Private Sub btnStart_Click(sender As Object, e As EventArgs) Handles btnStart.Click

        StartDecoding()

    End Sub

    Private Sub btnStop_Click(sender As Object, e As EventArgs) Handles btnStop.Click

        StopDecoding()

    End Sub

    ' Background thread procedure used by BackgroundWorker
    Private Sub BackgroundWorker_DoWork(sender As Object, e As DoWorkEventArgs)

        Dim worker As BackgroundWorker = CType(sender, BackgroundWorker)
        Dim barcodeTypesToFind As BarcodeTypeSelector = CType(e.Argument, BarcodeTypeSelector)

        ' Create and setup barcode reader instance
        Using reader As New Reader

            reader.RegistrationName = "demo"
            reader.RegistrationKey = "demo"

            reader.BarcodeTypesToFind = barcodeTypesToFind

            ' Work while not canceled
            While True

                ' Check cancellation
                If worker.CancellationPending Then
                    e.Cancel = True
                    _synchronizationEvent.Set()
                    Return
                End If

                ' Get image from camera by invoking method from UI thread
                Dim bitmap As Bitmap = CType(Invoke(New GetCameraImageDelegate(AddressOf GetCameraImage)), Bitmap)
                If bitmap Is Nothing Then
                    e.Result = nothing
                    return
                End If

                ' -----------------------------------------------------------------------
                ' NOTE: We can read barcodes from specific page to increase performance .
                ' For sample please refer to "Decoding barcodes from PDF by pages" program.
                ' ----------------------------------------------------------------------- 

                ' Search the image for barcodes
                Dim result As FoundBarcode() = reader.ReadFrom(bitmap)

                ' Update UI asynchronously
                BeginInvoke(New Action(Of FoundBarcode())(AddressOf UpdateStatus), New Object() { result })

                ' Pause
                Thread.Sleep(SCAN_DELAY)

            End While

        End Using

    End Sub

    Delegate Function GetCameraImageDelegate() As Bitmap

    Private Function GetCameraImage() As Bitmap

        If Not IsDisposed and Not Disposing and _touchlessLibManager.CurrentCamera IsNot Nothing Then
            return _touchlessLibManager.CurrentCamera.GetCurrentImage()    
        End If

        Return Nothing

    End Function

    ' Update UI with found barcodes information
    Private Sub UpdateStatus(foundBarcodes As FoundBarcode())

        If foundBarcodes IsNot Nothing And foundBarcodes.Length > 0 Then

            ' Play sound if we found any barcode
            SystemSounds.Beep.Play()

            Dim stringBuilder As StringBuilder = New StringBuilder()

            stringBuilder.AppendFormat("Time: {0:HH:mm:ss:tt}", DateTime.Now)
            stringBuilder.AppendLine()

            ' Display found barcodes in the output text box
            For Each barcode As FoundBarcode In foundBarcodes
                stringBuilder.AppendFormat("Found barcode: {0} {1}", barcode.Type, barcode.Value)
                stringBuilder.AppendLine()
            Next

            rtbFoundBarcodes.Text = stringBuilder.ToString()

            ' Update status text with number of found barcodes
            lblFoundBarcodes.Text = String.Format("Found {0} barcodes:", foundBarcodes.Length)

        End If

        ' Make "Scanning..." label flicker.
        lblScanning.Visible = Not lblScanning.Visible
        lblScanning.Refresh()

        ' Check if we need to stop on first barcode found
        If cbStopOnFirstBarcode.Checked And foundBarcodes IsNot Nothing And foundBarcodes.Length > 0 Then
            StopDecoding()
        End If

    End Sub

    ' Background thread is finished
    Private Sub BackgroundWorker_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs)

        ' Update UI asynchronously
        BeginInvoke(New Action(Of RunWorkerCompletedEventArgs)(AddressOf OnBackgroundWorkerFinished), New Object() {e})

    End Sub

    Private Sub OnBackgroundWorkerFinished(completedEventArgs As RunWorkerCompletedEventArgs)

        If completedEventArgs.Cancelled Then
            lblScanning.Text = "Stopped"
        ElseIf completedEventArgs.Error IsNot Nothing Then
            lblScanning.Text = "Error: " + completedEventArgs.Error.Message
        Else
            lblScanning.Text = "Done!"
        End If

        UpdateControls(False)

    End Sub

    Private Function GetBarcodeTypeFromCombobox() As BarcodeTypeSelector

        Dim result As BarcodeTypeSelector = New BarcodeTypeSelector()

        Dim selectedBarcodeTypeName As String = CType(cmbBarcodeType.SelectedItem, String)

        Dim propertyInfo As PropertyInfo = GetType(BarcodeTypeSelector).GetProperty(selectedBarcodeTypeName)
        propertyInfo.SetValue(result, True, Nothing)

        Return result

    End Function

    Protected Overrides Sub OnClosing(e As CancelEventArgs)

        StopDecoding()

        _touchlessLibManager.Dispose()

        MyBase.OnClosing(e)

    End Sub

    Private Sub btnExit_Click(sender As Object, e As EventArgs) Handles btnExit.Click

        DialogResult = DialogResult.OK
        Close()

    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

        Try
            if _touchlessLibManager.CurrentCamera IsNot Nothing
                _touchlessLibManager.CurrentCamera.ShowPropertiesDialog(Handle)
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

    End Sub
End Class

Imports System.Collections.Generic
Imports System.Windows.Forms

NotInheritable Class Program
    Private Sub New()
    End Sub
    ''' <summary>
    ''' The main entry point for the application.
    ''' </summary>
    <MTAThread> _
    Friend Shared Sub Main()
        Application.EnableVisualStyles()
        Application.SetCompatibleTextRenderingDefault(False)

        Dim dlg As New MainForm()
        dlg.ShowDialog()
    End Sub
End Class