VintaSoft Twain .NET SDK 15.5: Documentation for .NET developer
In This Topic
How to acquire an image area from WIA scanner?
In This Topic
If you want to acquire an image area (not the whole image) from WIA scanner, you should use the WiaDevice.SetImageLayout method.

Current image scan region can be get using the WiaDevice.GetImageLayout method.
The minimum image scan region can be get using the WiaDevice.GetMinimumImageLayout method.
The maximum image scan region can be get using the WiaDevice.GetMaximumImageLayout method.

Here is an example that demonstrates how to acquire an image region from WIA device:
/// <summary>
/// Acquires image area from WIA image scanner.
/// </summary>
public void AcquireImageRegionFromWiaDevice()
{
    // create WIA device manager
    using (Vintasoft.WiaImageScanning.WiaDeviceManager deviceManager = new Vintasoft.WiaImageScanning.WiaDeviceManager())
    {
        // open WIA device manager
        deviceManager.Open();

        // get count of WIA devices
        int deviceCount = deviceManager.Devices.Count;
        if (deviceCount == 0)
        {
            System.Console.WriteLine("Devices are not found.");
            return;
        }

        // select the first WIA device
        Vintasoft.WiaImageScanning.WiaDevice device = deviceManager.Devices[0];

        // open WIA device
        device.Open();

        // get current image layout
        Vintasoft.Primitives.VintasoftRect imageLayout = device.GetImageLayout();
        // set new image layout
        device.SetImageLayout(new Vintasoft.Primitives.VintasoftRect(0, 0, imageLayout.Width, imageLayout.Height / 2));

        Vintasoft.WiaImageScanning.WiaAcquiredImage acquiredImage;
        do
        {
            try
            {
                // acquire image from WIA device
                acquiredImage = device.AcquireImageSync();
                // if image is received
                if (acquiredImage != null)
                {
                    System.Console.WriteLine("Image is acquired.");
                }
                // if image is not received
                else
                {
                    System.Console.WriteLine("Scan is completed.");
                    break;
                }
            }
            catch (System.Exception ex)
            {
                System.Console.WriteLine(string.Format("Scan is failed: {0}", ex.Message));
                break;
            }
        }
        // while image is acquired
        while (acquiredImage != null);

        // close WIA device
        device.Close();

        // close WIA device manager
        deviceManager.Close();
    }

    System.Console.ReadLine();
}
''' <summary>
''' Acquires image area from WIA device.
''' </summary>
Public Sub AcquireImageRegionFromWiaDevice()
    ' create WIA device manager
    Using deviceManager As New Vintasoft.WiaImageScanning.WiaDeviceManager()
        ' open WIA device manager
        deviceManager.Open()

        ' get count of WIA devices
        Dim deviceCount As Integer = deviceManager.Devices.Count
        If deviceCount = 0 Then
            System.Console.WriteLine("Devices are not found.")
            Return
        End If

        ' select the first WIA device
        Dim device As Vintasoft.WiaImageScanning.WiaDevice = deviceManager.Devices(0)

        ' open WIA device
        device.Open()

        ' get the image layout
        Dim imageLayout As Vintasoft.Primitives.VintasoftRect = device.GetImageLayout()
        ' set the image layout
        device.SetImageLayout(New Vintasoft.Primitives.VintasoftRect(0, 0, imageLayout.Width, imageLayout.Height / 2))

        Dim acquiredImage As Vintasoft.WiaImageScanning.WiaAcquiredImage
        Do
            Try
                ' acquire image from WIA device
                acquiredImage = device.AcquireImageSync()
                ' if image is received
                If acquiredImage IsNot Nothing Then
                    System.Console.WriteLine("Image is acquired.")
                Else
                    ' if image is not received
                    System.Console.WriteLine("Scan is completed.")
                    Exit Try
                End If
            Catch ex As System.Exception
                System.Console.WriteLine(String.Format("Scan is failed: {0}", ex.Message))
                Exit Try
            End Try
            ' while image is acquired
        Loop While acquiredImage IsNot Nothing

        ' close WIA device
        device.Close()

        ' close WIA device manager
        deviceManager.Close()
    End Using

    System.Console.ReadLine()
End Sub