Acquire images directly to disk

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A lot of TWAIN scanning devices support the File transfer mode and allow to save acquired images directly to disk.
Transfer modes supported by device can be retrieved via Device_GetSupportedTransferModes method.

A lot of TWAIN scanning devices can save acquired images as BMP files. Advanced devices can save acquired images as TIFF, JPEG, PDF, etc files.
File formats supported by device can be retrieved via Device_GetSupportedImageFileFormats method.
File format compressions supported by device can be retrieved via Device_GetSupportedImageCompressions method.

Example: Here is an example that shows how to save acquired images directly to a disk as JPEG files with image quality value 70%.

VB.NET

Private VSTwain1 As New VintaSoftTwain()
Private imageCount As Integer


''' <summary>
''' Scans images asynchronously.
''' </summary>
Private Sub ScanImages()
    ' open the device manager
    If Not VSTwain1.DeviceManager_Open() Then
        Console.WriteLine(VSTwain1.errorString)
        Exit Sub
    End If

    ' open the device
    If Not VSTwain1.Device_Open Then
        Console.WriteLine(VSTwain1.errorString)
        Exit Sub
    End If

    ' scan images without UI
    VSTwain1.Device_ShowUI = False

    ' specify that device must save acquired images directly to disk
    VSTwain1.Device_TransferMode = TRANSFERMODE.TRANSFERMODE_File
    ' specify that acquired images must be save as JPEG files
    VSTwain1.Device_FileFormat = TWAINIMAGEFILEFORMAT.TWAINIMAGEFILEFORMAT_Jpeg
    ' specify the quality of JPEG images
    VSTwain1.Device_FileJpegQuality = 70
    ' initialize the image count
    imageCount = 1
    ' specify the name of file where acquired image must be saved
    VSTwain1.Device_FileName = Str(imageCount) + ".jpg"

    ' subscribe to the device events
    AddHandler VSTwain1.DeviceImageAcquired, AddressOf VSTwain1_ImageAcquired
    AddHandler VSTwain1.DeviceScanCompleted, AddressOf VSTwain1_ScanCompleted
    AddHandler VSTwain1.DeviceScanFailed, AddressOf VSTwain1_ScanFailed
    AddHandler VSTwain1.DeviceScanCanceled, AddressOf VSTwain1_ScanCanceled

    ' acquire images asynchronously
    VSTwain1.Device_AcquireImage()
End Sub

Private Sub VSTwain1_ImageAcquired()
    ' increment the image count
    imageCount = imageCount + 1
    ' specify the name of file where acquired image must be saved
    VSTwain1.Device_FileName = Str(imageCount) + ".jpg"
End Sub

Private Sub VSTwain1_ScanCompleted()
    Console.WriteLine("Scan is completed.")
End Sub

Private Sub VSTwain1_ScanFailed(errorString As String)
    Console.WriteLine(String.Format("Scan is failed: {0}.", errorString))
End Sub

Private Sub VSTwain1_ScanCanceled()
    Console.WriteLine("Scan is canceled.")
End Sub

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