C# PDF Parser Library
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How to Save Acquired PDF Image to File in C#.NET with TWAIN Add-on
Overview
If you want to acquire an image directly into the C#.NET application in which you are going to work with the image, you'd better use the widely used application programming interface - TWAIN. TWAIN is not a hardware-level protocol, but a communication protocol that realizes connection between software and digital imaging devices.
Using our C#.NET TWAIN Add-On, you are capable of scanning images from digital imaging devices (such as TWAIN compatible scanners and digital cameras) automatically and saving the images to file in C#.NET application.
Scan multiple images into one PDF
To accomplish this kind of C#.NET TWAIN scanning, it is indispensable to set up some events to assist with the process of scanning from device and convert the images obtained to form a PDF document.
AcquireCanceled: Raised if C# user cancels TWAIN acquisition process.
AcquireCompleted: Raised when the scanner has finished scanning the last page.
ImageAcquired: Raised each time the scanner finishes scanning a page.
C#.NET TWAIN Scanning Demo Code: Scan multiple images into one PDF
Following C# demo code can scan multiple pages into one PDF document in C#.NET project within seconds. Note: you need to reference above mentioned DLL assemblies to your project to complete the following functions.
private bool _acquireCanceled;
private List<RasterImage> _imageList;
public void ScanImages()
{
_acquireCanceled = false;
Acquisition myAcquisition = new Acquisition();
myAcquisition.AcquireCanceled += new AcquireCanceledEventHandler(OnAcquireCanceled);
myAcquisition.AcquireCompleted += new AcquireCompletedEventHandler(OnAcquireCompleted);
myAcquisition.ImageAcquired += new ImageAcquiredEventHandler(OnImageAcquired);
TWAINDevice device = myAcquisition.DefaultDevice;
device.Open();
device.ScanSetting.ShouldTransferAllPages = true;
_imageList = new List<RasterImage>();
device.Acquire();
}
private void OnImageAcquired(object sender, ImageAcquiredEventArgs args)
{
if (args.OutputImage != null)
{
// add scaned images to image collection
_imageList.Add(args.OutputImage);
}
}
private void OnAcquireCanceled(object sender, EventArgs args)
{
_acquireCanceled = true;
}
private void OnAcquireCompleted(object sender, AcquireCompletedEventArgs args)
{
if (_acquireCanceled)
return;
Bitmap[] bmps = new Bitmap[_imageList.Count];
int index = 0;
foreach (RasterImage image in _imageList)
{
bmps[index++] = image.ToBitmap();
}
index =0;
REImage[] imageList = new REImage[bmps.Length];
foreach (Bitmap bmp in bmps)
{
imageList[index++] = new REImage(bmp);
}
// form a PDF document using image collection scanned
PDFDocument doc = new PDFDocument(imageList);
// save PDF document
doc.Save(@"c:\ScannedPDF.pdf");
doc.Dispose();
}
