Using the Magnifying Glass (Visual Basic)

Take the following steps to enable the generation of the MagGlassExt 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 and LEAD Raster Variant Object Library to your project
	On the Project pull-down menu, use the References option, and select the LEAD Raster Object Library (14.5).
	On the Project pull-down menu, use the References option, and select the LEAD Raster Variant Object Library (14.5).
5.	Add the LEAD RasterIO Object Library 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 = APPEARANCE_FLAT
    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_INTERNET, "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

    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_MagGlassExt event as follows:

Private Sub LEADRasterView1_MagGlassExt(ByVal nMaskPlaneStart As Long, ByVal nMaskPlaneEnd As Long, ByVal vMaskPlane As LEADRasterVariant)
    Dim nRet As Integer

    gnCommandID = gnCommandID + 1

    nRet = LEADNet1.InetSendGetMagGlassDataCmd(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_InetReceiveCmd event as follows:

Private Sub LEADNet1_InetReceiveCmd(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 LEADRasterVariant)
    Dim nStatus As Integer
    Dim vColorBuffer As LEADRasterVariant

    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).StringValue, Params.ParamValue(1).LongValue, 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.InetSendLoadRsp 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.InetGetMagGlassData(LEADRasterView1.Raster, vColorBuffer, Params.ParamValue(2).StringValue, Params.ParamValue(3).LongValue, Params.ParamValue(4).LongValue)

                        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.InetSendGetMagGlassDataRsp nCommandID, vColorBuffer.StringValue, Params.ParamValue(2).StringValue, Params.ParamValue(3).LongValue, Params.ParamValue(4).LongValue, 0, Null, nStatus
                Exit Sub
        End Select
    End If

    LEADNet1.InetSendRsp InetCommand, nCommandID, Nothing, 0, Null, nStatus
End Sub

25.	Code the LEADNet1_InetReceiveRsp event as follows:

Private Sub LEADNet1_InetReceiveRsp(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.UpdateMagGlass(CVar(Params.ParamValue(1)), CVar(Params.ParamValue(3)), Params.ParamValue(4), Params.ParamValue(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.