IC Imaging Control ActiveX

Making Device Settings

Making Device Settings

This chapter shows you how to create a custom device settings dialog. The code is provided in reusable form, thus it can be easily integrated into your own applications.

IC Imaging Control also offers a built-in dialog, which can be used to select and set up a device. If, however, the dialog provided by IC Imaging Control does not fit your needs, this chapter shows you how to create a custom dialog. It will first show you how to integrate the sample code into your own projects and then how to actually build the dialog.

Integrating the sample code into your project

The sample code for this example can be found in the samples\VB6\Making Device Settings directory. To integrate the code into your project, you just have to add the file frmDeviceSettings.frm. Select Project from the menu and then select Add Form. In the Add Form dialog click on the Existing tab. Now browse to the sample folder and open the file frmDeviceSettings.frm.

To call the dialog from your application, just 2 lines of code are needed. First, the ICImagingControl instance that you are using in your application (here: ICImagingControl1 ) must be assigned to the dialog. Then the dialog has to be called. To do this, just insert the following lines at an appropriate place into your code.

Set frmDeviceSettings.ImagingControl = ICImagingControl1
frmDeviceSettings.Show vbModal

Creating the Dialog

In this chapter, we will focus on the device settings dialog. In addition to the dialog, you will of course need an application that calls it. The sample code of this chapter contains a ready-to-run project with a small application that calls the dialog.

Assuming you have already set up a main project, you now have to add a new form to the project. This form will contain the elements of the custom dialog. To add a new form, select Project from the menu and then choose Add Form. Choose the Dialog type of form. Name the form frmDeviceSettings.

Now add 5 combo boxes to the form. Name them cboDevice, cboVideoNorm, cboVideoFormat, cboFrameRate and cboInputChannel. Also add a text box, called txtSerial and two check boxes named chkFlipV and chkFlipH.

In addition to the controls mentioned above, the sample dialog also contains a label named lblErrorMessage. The Visible property of this label is set to false, so that it will not be displayed when the dialog is called. The reason for this is explained when the Form_Load event is discussed.

image

Adding Functionality to the Dialog

First, we need a global data structure that will store the state of the device. This is necessary since that state has to be restored, if the user clicks the Cancel button of the dialog. For this sample, the data structure looks as follows:

Private Type Settings
    DeviceAvail As Boolean
    Device As String

    VideoNormAvail As Boolean
    VideoNorm As String

    VideoFormat As String

    FrameRateAvail As Boolean
    FrameRate As Double

    InputChannelAvail As Boolean
    InputChannel As String

    FlipVAvail As Boolean
    FlipV As Boolean

    FlipHAvail As Boolean
    FlipH As Boolean
End Type

Now add some global variables:

Public ImagingControl As ICImagingControl
Private DeviceState As Settings
Const NOT_AVAILABLE = "n/a"

ImagingControl must be public since it is assigned from the main program before the dialog is called.

Now add a Form_Load event and insert the following code:

Private Sub Form_Load()
    If ImagingControl.DeviceValid Then
        If ImagingControl.LiveVideoRunning Then
            lblDevice.Visible = False
            lblVideoNorm.Visible = False
            lblVideoFormat.Visible = False
            lblFrameRate.Visible = False
            lblInputChannel.Visible = False
            lblSerial.Visible = False
            cboDevice.Visible = False
            cboVideoNorm.Visible = False
            cboVideoFormat.Visible = False
            cboFrameRate.Visible = False
            cboInputChannel.Visible = False
            txtSerial.Visible = False
            chkFlipV.Visible = False
            chkFlipH.Visible = False
            CancelButton.Visible = False

            Me.Caption = "Error"
            Me.Width = 3465
            Me.Height = 2175

            OKButton.Top = 85
            OKButton.Left = 134

            lblErrorMessage.Caption = "The device settings dialog is not available while the live video is running." _
                                    & vbCrLf & vbCrLf & "Stop the live video first."
            lblErrorMessage.Visible = True
            Exit Sub
        End If
    End If

    SaveDeviceSettings

    UpdateDevices
End Sub

The Form_Load event checks, whether the live video is running. If it is, it reformats the dialog box to display a message to tell you that the dialog will not be displayed, while the live video is running. This behavior was implemented to point out that changing the device will cause side effects. The ring buffer collection ICImagingControl.ImageBuffers is reset when the device is changed. Therefore, image data in the collection is lost.

Now add the click events of the OK and the Cancel button and insert the following code accordingly:

Private Sub OKButton_Click()
    Unload Me
End Sub
Private Sub CancelButton_Click()
    RestoreDeviceSettings

    Unload Me
End Sub

As can be seen above, the Form_Load event calls a procedure SaveDeviceSettings and the CancelButton_Click event calls RestoreDeviceSettings. These are two helper procedures that fill and read out the global data structure DeviceState to save\restore the state of the device.

The UpdateDevices procedure that is called on the Form_Load event updates the controls of the dialog, but this will be discussed later.

Now add the click events for all 5 combo boxes and the 2 check boxes. On the click event of the device combo box, the currently selected device must be changed and all other combo boxes, the check boxes and the display of the serial number text field must be updated. This is done with the following code:

Private Sub cboDevice_Click()
    Dim Serial As String

    On Error GoTo err_cboDevice_Click
        'Open the device
        If cboDevice.Enabled Then
            Dim Item As Variant
            Dim index As Integer
            index = 1

            ImagingControl.Device = cboDevice.Text
            txtSerial.Text = NOT_AVAILABLE

            For Each Item In ImagingControl.Devices
                If Item.Name = cboDevice.Text Then
                    If ImagingControl.Devices.Item(index).GetSerialNumber(Serial) Then
                        txtSerial.Text = Serial
                        Exit For
                    End If
                End If
                index = index + 1
            Next

            ' Get supported video norms, formats and inputs
            UpdateVideoNorms
            UpdateInputChannels
            UpdateFlip
        End If

    Exit Sub
err_cboDevice_Click:
    MsgBox Err.Description
End Sub

After the new device is selected, its serial number is retrieved. If a serial number is not available, n/a is displayed. The procedures UpdateVideoNorms, UpdateInputChannels and UpdateFlip update the controls. They will be discussed later. Please note that the video format and the frame rate are updated implicitly by UpdateVideoNorms and UpdateVideoFormat.

The click events for the other combo boxes are quite similar. The click event for the cboVideoNorm combo box includes a procedure UpdateVideoFormats, which is used to update the video format combo box according to the selected video norm. The click event for the cboVideoFormat combo box includes a procedure UpdateFrameRates that updates the frame rate combo box after the video format has changed. The other combo boxes just set the currently selected value. Here is the code for the video norm combo box:

Private Sub cboVideoNorm_Click()
    On Error GoTo err_cboVideoNorm_Click

    If cboVideoNorm.Enabled Then
        ImagingControl.VideoNorm = cboVideoNorm.Text
    End If

    UpdateVideoFormats

    Exit Sub
err_cboVideoNorm_Click:
    MsgBox Err.Description
End Sub

The click events for the other combo boxes are implemented accordingly, except a minor detail, regarding the frame rate combo box. If you assign the new value for the frame rate, make sure you do a typecast, since cboFrameRate.Text returns a string, but ICImagingControl.DeviceFrameRate needs a floating point value.

Finally, add click events for the check boxes. They just toggle the horizontal and vertical flip:

Private Sub chkFlipV_Click()
    If ImagingControl.DeviceFlipVerticalAvailable Then
        ImagingControl.DeviceFlipVertical = (chkFlipV.Value = 1)
    End If
End Sub

The event for chkFlipH is implemented the same way.

The Update Procedures

As mentioned before, there is an Update procedure for every combo box and one for the two check boxes. The Update procedures for the combo boxes just fill the appropriate combo box with currently valid values. If the value that was selected before the update is still contained in the combo box, it is selected automatically. The code for the UpdateDevice procedure looks as follows:

Private Sub UpdateDevices()
    cboDevice.Clear
    If ImagingControl.Devices.Count > 0 Then
        Dim Item As Variant
        Dim index As Long

        For Each Item In ImagingControl.Devices
            cboDevice.AddItem Item.Name
        Next

        If ImagingControl.DeviceValid Then
            index = ImagingControl.Devices.FindIndex(ImagingControl.Device)
            cboDevice.ListIndex = index - 1
        Else
            cboDevice.ListIndex = 0
        End If
        cboDevice.Enabled = True
    Else
        cboDevice.AddItem NOT_AVAILABLE
        cboDevice.Enabled = False
        cboDevice.ListIndex = 0
    End If

End Sub

The Update procedures for the other combo boxes are implemented accordingly, but note that ImagingControl.DeviceFrameRates returns a collection that contains floating point values. Therefore, in the UpdateFrameRates procedure, you must typecast them into a string before you can add them to the combo box.

The UpdateFlip procedure checks whether there is a vertical or horizontal flip available with the current device and sets their current state if possible:

Private Sub UpdateFlip()
    If ImagingControl.DeviceFlipHorizontalAvailable Then
        chkFlipH.Enabled = True
        If ImagingControl.DeviceFlipHorizontal Then
            chkFlipH.Value = 1
        Else
            chkFlipH.Value = 0
        End If
    Else
        chkFlipH.Enabled = False
        chkFlipH.Value = 0
    End If

    If ImagingControl.DeviceFlipVerticalAvailable Then
        chkFlipV.Enabled = True
        If ImagingControl.DeviceFlipVertical Then
            chkFlipV.Value = 1
        Else
            chkFlipV.Value = 0
        End If
    Else
        chkFlipV.Enabled = False
        chkFlipV.Value = 0
    End If
End Sub

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