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Programming / TIFF / Creating a multipage TIFF file from a document in the scanner using the TWAIN protocol

Creating a multipage TIFF file from a document in the scanner using the TWAIN protocol

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In this tutorial, we will create a multipage TIFF file from scans of a document, that is in the scanner feeder. We will set the image bit depth to 1 bit per pixel and we will scan the images to black and white. For the communication with the scanner we will use the TWAIN protocol.

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'We assume that GdPicture has been correctly installed and unlocked.
Dim oGdPictureImaging As New GdPictureImaging()
'Variable to hold image identifiers.
Dim imageId As Integer = 0
'Variable to hold created multipage image handle.
Dim multipageHandle As Integer = 0
'Number of images.
Dim imageCount As Integer = 0
'Setting up the Twain features.
oGdPictureImaging.TwainOpenDefaultSource(Me.Handle)
'Enabling AutoFeed option.
oGdPictureImaging.TwainSetAutoFeed(True)
'To achieve the maximum scanning rate.
oGdPictureImaging.TwainSetAutoScan(True)
'1 bit bw image
oGdPictureImaging.TwainSetPixelType(TwainPixelType.TWPT_BW)
'Setting duplex acquisition if supported.
oGdPictureImaging.TwainEnableDuplex(True)
'Asking the device to hide its GUI.
oGdPictureImaging.TwainSetHideUI(True)

'Scanning each page and adding it to a multipage TIFF GdPictureImage identifier.
Dim status As GdPictureStatus = GdPictureStatus.OK
Do
    'Acquiring an image from the scanner.
    imageId = oGdPictureImaging.TwainAcquireToGdPictureImage(Me.Handle)
    'Checking, if the image has been loaded successfully.
    status = oGdPictureImaging.GetStat()
    If status = GdPictureStatus.OK Then
        imageCount += 1
        'If it is the first image, then create a new multipage tiff file.
        If imageCount = 1 Then
            multipageHandle = imageId
            status = oGdPictureImaging.TiffSaveAsMultiPageFile(multipageHandle, "multipage.tif", TiffCompression.TiffCompressionAUTO)
        Else
            'If it is the second image or more, add it to the previously created multipage tiff file.
            status = oGdPictureImaging.TiffAddToMultiPageFile(multipageHandle, imageId)
            'Releasing the current image to minimize memory usage.
            oGdPictureImaging.ReleaseGdPictureImage(imageId)
        End If
    Else
        MessageBox.Show("The image can't be loaded. Error:" + status.ToString(), "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End If
    If status <> GdPictureStatus.OK Then
        Exit Do
    End If
Loop While oGdPictureImaging.TwainGetState() > TwainStatus.TWAIN_SOURCE_ENABLED
If status = GdPictureStatus.OK Then
    MessageBox.Show("Done!", "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Information)
Else
    MessageBox.Show("Error: " + status.ToString(), "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Error)
End If
'Cleaning up resources.
'Closing the source
oGdPictureImaging.TwainCloseSource()
'Closing the multipage file.
oGdPictureImaging.TiffCloseMultiPageFile(multipageHandle)
'Releasing the multipage image.
oGdPictureImaging.ReleaseGdPictureImage(multipageHandle)
oGdPictureImaging.Dispose()
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//We assume that GdPicture has been correctly installed and unlocked.
GdPictureImaging oGdPictureImaging = new GdPictureImaging();
//Variable to hold image identifiers.
int imageId = 0;
//Variable to hold created multipage image handle.
int multipageHandle = 0;
//Number of images.
int imageCount = 0;
//Setting up the Twain features.
oGdPictureImaging.TwainOpenDefaultSource(this.Handle);
oGdPictureImaging.TwainSetAutoFeed(true); //Enabling AutoFeed option.
oGdPictureImaging.TwainSetAutoScan(true); //To achieve the maximum scanning rate.
oGdPictureImaging.TwainSetPixelType(TwainPixelType.TWPT_BW); //1 bit bw image
oGdPictureImaging.TwainEnableDuplex(true); //Setting duplex acquisition if supported.
oGdPictureImaging.TwainSetHideUI(true); //Asking the device to hide its GUI.
GdPictureStatus status = GdPictureStatus.OK;
//Scanning each page and adding it to a multipage TIFF GdPictureImage identifier.
do
{
    //Acquiring an image from the scanner.
    imageId = oGdPictureImaging.TwainAcquireToGdPictureImage(this.Handle);
    //Checking, if the image has been loaded successfully.
    status = oGdPictureImaging.GetStat();
    if (status == GdPictureStatus.OK)
    {
        imageCount++;
        //If it is the first image, then create a new multipage tiff file.
        if (imageCount == 1)
        {
            multipageHandle = imageId;
            status = oGdPictureImaging.TiffSaveAsMultiPageFile(multipageHandle, "multipage.tif", TiffCompression.TiffCompressionAUTO);
        }
        else //If it is the second image or more, add it to the previously created multipage tiff file.
        {
            status = oGdPictureImaging.TiffAddToMultiPageFile(multipageHandle, imageId);
            //Releasing the current image to minimize memory usage.
            oGdPictureImaging.ReleaseGdPictureImage(imageId);
        }
    }
    else
        MessageBox.Show("The image can't be loaded. Error: " + status.ToString(), "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Error);
    if (status != GdPictureStatus.OK)
        break;
} while (oGdPictureImaging.TwainGetState() > TwainStatus.TWAIN_SOURCE_ENABLED);
if (status == GdPictureStatus.OK)
    MessageBox.Show("Done!", "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Information);
else
    MessageBox.Show("Error: " + status.ToString(), "Multipage TIFF Example", MessageBoxButtons.OK, MessageBoxIcon.Error);
//Cleaning up resources.
oGdPictureImaging.TwainCloseSource(); //Closing the source.
oGdPictureImaging.TiffCloseMultiPageFile(multipageHandle); //Closing the multipage file.
oGdPictureImaging.ReleaseGdPictureImage(multipageHandle); //Releasing the multipage image.
oGdPictureImaging.Dispose();