VintaSoft Twain .NET SDK 15.0: Documentation for .NET developer
In This Topic
    How to acquire an image area from SANE scanner?
    In This Topic
    If you want to acquire an image area (not the whole image) from SANE scanner, you should set the scan area using SaneLocalDevice.ScanArea property.

    Here is an example that demonstrates how to acquire an image area from SANE device:
    /// <summary>
    /// Acquires image area from SANE device.
    /// </summary>
    public void AcquireImageAreaFromSaneDevice()
    {
        // create SANE device manager
        using (Vintasoft.Sane.SaneLocalDeviceManager deviceManager = new Vintasoft.Sane.SaneLocalDeviceManager())
        {
            // open SANE device manager
            deviceManager.Open();
    
            // get count of SANE devices
            int deviceCount = deviceManager.Devices.Count;
            if (deviceCount == 0)
            {
                System.Console.WriteLine("Devices are not found.");
                return;
            }
    
            // select the first SANE device
            Vintasoft.Sane.SaneLocalDevice device = deviceManager.Devices[0];
    
            // open SANE device
            device.Open();
    
    
            // get the default scan area
            VintasoftRectF defaultScanArea = device.ScanArea;
            // set new scan area
            device.ScanArea = new VintasoftRectF(0, 0, defaultScanArea.Width, defaultScanArea.Height / 2);
    
    
            Vintasoft.Sane.SaneAcquiredImage acquiredImage;
            do
            {
                try
                {
                    // acquire image from SANE 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 device has more images to scan
            while (device.HasMoreImagesToScan);
    
            // close SANE device
            device.Close();
    
            // close SANE device manager
            deviceManager.Close();
        }
    
        System.Console.ReadLine();
    }
    
    ''' <summary>
    ''' Acquires image area from SANE device.
    ''' </summary>
    Public Sub AcquireImageAreaFromSaneDevice()
            ' create SANE device manager
            Using deviceManager As New Vintasoft.Sane.SaneLocalDeviceManager()
                    ' open SANE device manager
                    deviceManager.Open()
    
                    ' get count of SANE 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 SANE device
                    Dim device As Vintasoft.Sane.SaneLocalDevice = deviceManager.Devices(0)
    
                    ' open SANE device
                    device.Open()
    
    
                    ' get the default scan area
                    Dim defaultScanArea As VintasoftRectF = device.ScanArea
                    ' set new scan area
                    device.ScanArea = New VintasoftRectF(0, 0, defaultScanArea.Width, defaultScanArea.Height / 2)
    
    
                    Dim acquiredImage As Vintasoft.Sane.SaneAcquiredImage
                    Do
                            Try
                                    ' acquire image from SANE 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 device has more images to scan
                    Loop While device.HasMoreImagesToScan
    
                    ' close SANE device
                    device.Close()
    
                    ' close SANE device manager
                    deviceManager.Close()
            End Using
    
            System.Console.ReadLine()
    End Sub