Using the Magnifying Glass (2) (Visual Basic)

Take the following steps to enable the generation of the MagGlassExt2 event and update the zoomed image using the LEADTOOLS Internet toolkit.

1.	Start Visual Basic. Select Standard EXE and click Open.
2.	Add the LEAD RasterView Control (14.5) to your project.
	On the Project pull-down menu, use the Components option, and select the LEAD RasterView Control (14.5).
3.	Add the LEAD Raster Internet Object Library (14.5) to your project.
	On the Project pull-down menu, use the References option, and select the LEAD Raster Internet Object Library (14.5).
4.	Add the LEAD Raster Object Library (14.5) to your project.
	On the Project pull-down menu, use the References option, and select the LEAD Raster Object Library (14.5).
5.	Add the LEAD RasterIO Object Library (14.5) to your project.
	On the Project pull-down menu, use the References option, and select the LEAD RasterIO Object Library (14.5).
6.	Select the LEAD RasterView control; then add the control to your main form. Size and position the control as you want it to appear at run time.
7.	Add seven command buttons to your main form and name them as follows:

	Name	Caption
	StartUpServer	Start Up Server
	ShutDownServer	Shut Server Down
	ConnectToRemoteServer	Connect To Remote Server
	DisconnectFromRemoteServer	Disconnect From Remote Server
	LoadRemoteImage	Load Remote Image
	StartMagnifyingGlass	Start Magnifying Glass
	StopMagnifyingGlass	Stop Magnifying Glass
8.	Add a Text box to your main form and name it as follows:
	Name
	RemoteComputer
9.	Set the Text property to the name of the computer you will use as a server, or set it to 10.0.32.241.
10.	Define the following global variables:

Dim hServer As Integer ' handle to server
Dim gnCommandID As Long
Dim bMagGlass As Boolean
Public WithEvents RasterIO As LEADRasterIO
Public WithEvents LEADNet1 As LEADRasterInet

11.	Add the following initialization code to the main form's Load procedure. In online help, you can use the Edit pull-down menu to copy the block of code.

Private Sub Form_Load()
   Dim Factory As New LEADRasterFactory
   Dim LEADRaster As LEADRaster
   Dim szLic As String

   ' Initialize some variables
   hServer = 0
   gnCommandID = 0
   bMagGlass = False

   ' Set defaults for displaying the image.
   ' These are all persistent properties that can be set in the properties box.
   LEADRasterView1.Appearance = 1
   LEADRasterView1.BorderStyle = 1
   LEADRasterView1.BackColor = RGB(255, 255, 125)
   LEADRasterView1.PaintDither = PAINTDITHER_DIFFUSION
   LEADRasterView1.PaintPalette = PAINTPALETTE_AUTO
   LEADRasterView1.AutoRepaint = True
   LEADRasterView1.AutoSize = False
   LEADRasterView1.AutoSetRects = True
   LEADRasterView1.PaintSizeMode = PAINTSIZEMODE_FIT

   ' Create the Raster IO and Raster Inet objects
   Set RasterIO = CreateObject("LEADRasterIO.LEADRasterIO")
   Set LEADNet1 = CreateObject("LEADRasterInet.LEADRasterInet")

   ' Create a temp LEADRaster object and use it
   ' to unlock support for the Inet object
   szLic = "LEADTOOLS OCX Copyright (c) 1991-2005 LEAD Technologies, Inc."
   Set LEADRaster = Factory.CreateObject("LEADRaster.LEADRaster", szLic)
   LEADRaster.UnlockSupport L_SUPPORT_LTPRO, "TestKey"

   ' Stop generation of runtime exceptions for LEAD RasterView Control, LEAD
   ' RasterIO Object Library and LEAD Raster Internet Object Library.
   LEADRasterView1.EnableMethodErrors = False
   RasterIO.EnableMethodErrors = False
   LEADNet1.EnableMethodErrors  = False
End Sub

12.	Code the main form's Form_Unload procedure as follows:

Private Sub Form_Unload(Cancel As Integer)
   Dim i As Integer
   Dim num As Integer

   ' Disconnect all connections
   num = LEADNet1.ConnectListNum
   For i = 0 To LEADNet1.ConnectListNum – 1
      LEADNet1.InetDisconnect LEADNet1.ConnectList (i)
   Next I

   If bMagGlass Then
      LEADRasterView1.StopMagGlass
   End If
End Sub

13.	Code the StartUpServer button's click procedure as follows:

Private Sub StartUpServer_Click()
   Dim nRet As Integer

   ' Initialize server on port 1000
   nRet = LEADNet1.InetServerInit (1000)
   hServer = LEADNet1.InetServerHandle

   If nRet <> 0 Then
      MsgBox "Error Initializing server: " + CStr(nRet)
   End If
End Sub

14.	Code the ShutDownServer button's click procedure as follows:

Private Sub ShutDownServer_Click()
   Dim nRet As Integer

   If hServer <> 0 Then
      nRet = LEADNet1.InetServerClose (hServer)

      If nRet <> 0 Then
         MsgBox "Error Shutting Down server: " + CStr(nRet)
      Else
         hServer = 0
      End If
   End If
End Sub

15.	Code the LEADNet1_InetAccept event as follows:

Private Sub LEADNet1_InetAccept (ByVal iServer As Integer)
   Dim hComputer As Integer
   Dim hName As String
   Dim nRet As Integer

   nRet = LEADNet1.InetAcceptConnect (hServer)
   hComputer = LEADNet1.InetConnectedComputer

   If nRet <> 0 Then
      MsgBox "Error accepting connection: " + CStr(nRet)
      Exit Sub
   End If

   LEADNet1.InetGetHostName hComputer, HOST_NAME_DESCRP
   hName = LEADNet1.InetHostName
   ' Add to our list
   LEADNet1.SendList (LEADNet1.SendListNum) = hComputer
   MsgBox "Connection accepted from: " + hName
End Sub

16.	Code the ConnectToRemoteServer button's click procedure as follows:

Private Sub ConnectToRemoteServer_Click()
   Dim nRet As Integer

   ' Connect to remote computer on port 1000
   nRet = LEADNet1.InetConnect(RemoteComputer.Text, 1000)

   If nRet <> 0 Then
      MsgBox "Error connecting to " + RemoteComputer.Text + ": " + CStr(nRet)
   End If
End Sub

17.	Code the DisconnectFromRemoteServer button's click procedure as follows:

Private Sub DisconnectFromRemoteServer_Click()
   Dim nRet As Integer

   ' We are assuming only one connection in this example.
   ' Therefore, the handle to the remote computer will be
   ' in the first position in the SendList
   nRet = LEADNet1.InetDisconnect (LEADNet1.SendList (0))

   If nRet <> 0 Then
      MsgBox "Error disconnecting from remote: " + CStr(nRet)
   End If
End Sub

18.	Code the LEADNet1_InetConnected event as follows:

Private Sub LEADNet1_InetConnected (ByVal iComputer As Integer)
   Dim sRemote As String

   ' Get remote host name
   LEADNet1.InetGetHostName iComputer, HOST_NAME_DESCRP
   sRemote = LEADNet1.InetHostName

   ' Add this connection to our SendList
   LEADNet1.SendList (LEADNet1.SendListNum) = iComputer
   MsgBox "Successfully connected to remote computer: " + sRemote
End Sub

19.	Code the LEADNet1_InetDisconnected event as follows:

Private Sub LEADNet1_InetDisconnected (ByVal iComputer As Integer)
   If hServer = 0 Then
        MsgBox "Disconnect from remote server"
    Else
        MsgBox "Connection to remote computer closed"
    End If
End Sub

20.	Code the LoadRemoteImage button's click procedure as follows:

Private Sub LoadRemoteImage_Click()
   Dim nRet As Integer

   nRet = LEADNet1.InetSendLoadCmd (999, "v:\images\eagle.cmp", 0, 1)

   If ((nRet <> 0) And (nRet <> ERROR_DATA_QUEUED)) Then
      MsgBox "ERROR " & CStr(nRet) & " calling InetSendLoadCmd."
   End If
End Sub

21.	Code the StartMagnifyingGlass button's click procedure as follows:

Private Sub StartMagnifyingGlass_Click()
   Dim nRet As Integer

   If LEADRasterView1.Raster.Bitmap <> 0 And hServer = 0 Then
      ' Enable MagGlassExt event.
      If LEADRasterView1.EnableMagGlassEvent = False Then
         LEADRasterView1.EnableMagGlassEvent = True
      End If

      LEADRasterView1.RgnFrameType = 0

      ' Start the Magnifying Glass
      nRet = LEADRasterView1.StartMagGlass(100, 100, 400, RGB(255, 0, 0), RGB(128, 128, 128), True, 1, False, CROSSHAIR_FINE, True, True)

      If nRet = 0 Then
         bMagGlass = True
      End If
   End If
End Sub

22.	Code the StopMagnifyingGlass button's click procedure as follows:

Private Sub StopMagnifyingGlass_Click()
   Dim nRet As Integer

   If LEADRasterView1.Raster.Bitmap <> 0 And hServer = 0 Then
      nRet = LEADRasterView1.StopMagGlass

      If nRet = 0 Then
         bMagGlass = False
      End If
   End If
End Sub

23.	Code the LEADRasterView1_MagGlassExt2 event as follows:

Private Sub LEADRasterView1_MagGlassExt2(ByVal nMaskPlaneStart As Long, ByVal nMaskPlaneEnd As Long, ByVal vMaskPlane As Variant)
   Dim nRet As Integer

   gnCommandID = gnCommandID + 1

   nRet = LEADNet1.InetSendGetMagGlassDataCmd2 (gnCommandID, 0, vMaskPlane, nMaskPlaneStart, nMaskPlaneEnd)
   If ((nRet <> 0) And (nRet <> ERROR_DATA_QUEUED)) Then
      MsgBox "ERROR " & CStr(nRet) & " calling InetSendGetMagGlassDataCmd."
   End If
End Sub

24.	Code the LEADNet1_InetReceiveCmd2 event as follows:

Private Sub LEADNet1_InetReceiveCmd2 (ByVal iComputer As Integer, ByVal InetCommand As Integer, ByVal nCommandID As Long, ByVal nError As Integer, ByVal Params As LEADRasterInetLib.ILEADRasterInetPacket, ByVal nExtraDataSize As Long, ByVal ExtraData As Variant)
   Dim nStatus As Integer
   Dim vColorBuffer As Variant
   Dim nRet As Integer

   nStatus = ERROR_FEATURE_NOT_SUPPORTED

   If (nError <> 0) Then
      nStatus = ERROR_TRANSFER_ABORTED
   Else
      Select Case InetCommand
         Case INETCMD_LOAD
            ' check the validity of the parameters
            If ((Params.ParamCount = 4) And (Params.ParamType(0) = PARAM_TYPE_STRING) And (Params.ParamType(1) = PARAM_TYPE_INT32) And (Params.ParamType(2) = PARAM_TYPE_INT32) And (Params.ParamType(3) = PARAM_TYPE_UINT32)) Then
               nStatus = RasterIO.Load(LEADRasterView1.Raster, Params.ParamValue(0), Params.ParamValue(1), 1, 1)

               If nStatus <> 0 Then
                  MsgBox "Load Bitmap failed with error code: " & CStr(nRet)
               Else
                  nStatus = LEADNet1.InetSendBitmap (LEADRasterView1.Raster, FILE_CMP, 0, QFACTOR_PQ2)

                  If nStatus <> 0 Then
                     MsgBox "SendBitmap failed with error code: " & CStr(nRet)
                  End If
               End If
            Else
               nStatus = ERROR_INV_PARAMETER    ' Invalid parameters
            End If

            LEADNet1.InetSendLoadRsp2 nCommandID, 0, 0, Null, nStatus
            Exit Sub
         Case INETCMD_GET_MAGGLASS_DATA
            ' check the validity of the parameters
            If ((Params.ParamCount = 5) And (Params.ParamType(0) = PARAM_TYPE_UINT32) _
                And (Params.ParamType(1) = PARAM_TYPE_UINT32) And (Params.ParamType(2) = PARAM_TYPE_USTRING) _
                And (Params.ParamType(3) = PARAM_TYPE_INT32) And (Params.ParamType(4) = PARAM_TYPE_INT32)) Then
               If LEADRasterView1.Raster.Bitmap <> 0 Then
                  nStatus = LEADNet1.InetGetMagGlassData2 (LEADRasterView1.Raster, vColorBuffer, CVar(Params.ParamValue2(2)), Params.ParamValue2(3), Params.ParamValue2(4))
                  If nStatus <> 0 Then
                     MsgBox "InetGetMagGlassData failed with error code: " & CStr(nStatus)
                  End If
               Else
                  nStatus = ERROR_INV_PARAMETER   ' Invalid parameter
               End If
            Else
               nStatus = ERROR_INV_PARAMETER    ' Invalid parameters
            End If

            LEADNet1.InetSendGetMagGlassDataRsp2 nCommandID, CVar(vColorBuffer), CVar(Params.ParamValue2(2)), Params.ParamValue2(3), Params.ParamValue2(4), 0, Null, nStatus
            Exit Sub
      End Select
   End If
   LEADNet1.InetSendRsp2 InetCommand, nCommandID, Nothing, 0, Null, nStatus
End Sub

25.	Code the LEADNet1_InetReceiveRsp2 event as follows:

Private Sub LEADNet1_InetReceiveRsp2 (ByVal iComputer As Integer, ByVal InetCommand As Integer, ByVal nCommandID As Long, ByVal nError As Integer, ByVal nStatus As Integer, ByVal Params As LEADRasterInetLib.ILEADRasterInetPacket, ByVal nExtraDataSize As Long, ByVal ExtraData As Variant)
   Dim nRet As Integer

   If (nError <> 0) Then Exit Sub

   Select Case InetCommand
      Case INETCMD_LOAD:
         If nStatus <> 0 Then
            MsgBox "Load failed with error code: " + CStr(nStatus)
         End If
      Case INETCMD_GET_MAGGLASS_DATA
         If (nStatus = 0) Then
            If ((Params.ParamCount = 6) And (Params.ParamType(0) = PARAM_TYPE_UINT32) _
                And (Params.ParamType(1) = PARAM_TYPE_USTRING) And (Params.ParamType(2) = PARAM_TYPE_UINT32) _
                And (Params.ParamType(3) = PARAM_TYPE_USTRING) And (Params.ParamType(4) = PARAM_TYPE_INT32)) _
                And (Params.ParamType(5) = PARAM_TYPE_INT32) Then
               nRet = LEADRasterView1.UpdateMagGlass2(CVar(Params.ParamValue2(1)), CVar(Params.ParamValue2(3)), Params.ParamValue2(4), Params.ParamValue2(5), True)

               If (nRet <> 0) Then
                  MsgBox "UpdateMagGlass failed with error code: " & CStr(nRet)
               End If
            Else
               MsgBox "Invalid parameter passed to INETCMD_GET_MAGGLASS_DATA response"
            End If
         Else
            MsgBox "Get MagGlass Data from server with error code " & CStr(nStatus)
         End If
   End Select
End Sub

26.	Code the LEADNet1_InetReceiveBitmap event as follows:

Private Sub LEADNet1_InetReceiveBitmap (ByVal iComputer As Integer, ByVal hBitmap As Long)
LEADRasterView1.Raster.Bitmap = hBitmap
End Sub

27.	On the main menu, select File > Make .exe, specify a path for the exe file then press OK.
28.	Run the exe file two times to execute two applications.
29.	In the first application press Start Up Server button.
30.	In the second application fill the edit box with the IP address of the remote computer on which you started the first application as a server. Then, press the Connect To Remote Server button to connect to the specified address.
31.	Next, press the Load Remote Image button of application number two to load an image on the server. Then press the Start Magnifying Glass button to start the Magnifying Glass with Internet support. Press the left mouse button and move over the image to see the zoomed area using the Magnifying Glass with Internet support.