Converting Image Files to PDF

• Download demo project - 219.16 KB
• Download source - 225.23 KB

Introduction

Hello everybody! This is my first article here. It's nothing fancy, but it can save a lot of trouble if you need to include a simple image -> PDF convertor in your .NET application. Please forgive any spelling or grammar mistakes which may follow.

Background

Some time ago I needed a TIFF to PDF converter. I found this article called Convert Tiff To PDF, which is written in Visual C++ 6 and uses the CXImage library, as well as LibTIFF.

As that article says, it only suppots TIFF Image files in Fax formats, whatever that means. I haven't looked in depth, but probably that's the reason why, during my testing, out of these 18 TIFF sample files, only 11 were converted to something that Adobe Reader could understand. They contain scanned text (from books and handwritten), technical drawings and pictures, so I suppose they cover a wide range of sub-formats.

So after the few minutes of joy during which I thought I had found the perfect solution, I was back to Google to look for something else. Luckily I found the wonderful freeware Open Source library called PDFSharp, which saved the day.

Using the Code

The purpose of the PDFSharp libray is to create PDF files from scratch as easy as possible. The methods it exposes are symilar to the GDI+ ones in .NET. So you can imagine that writing a PDF file is like drawing 'stuff' (text, shapes, images) in the Paint event of a Windows Forms Panel. With that knowledge, converting a BMP/PNG/GIF/JPEG/TIFF file to a PDF one is done like this:

• create a new empty PDF document
• add a blank page
• get the XGraphics object
• create the XImage from the source file
• draw the image
• save the PDF file

The core of the program is listed below. I used a BackgroundWorker, so that the UI will not hang during the conversion.

                
     PdfDocument doc = new PdfDocument();
     doc.Pages.Add(new PdfPage());
     XGraphics xgr = XGraphics.FromPdfPage(doc.Pages[0]);
     XImage img = XImage.FromFile(source);

     xgr.DrawImage(img, 0, 0);
     doc.Save(destinaton);
     doc.Close();

Conclusion

Creating PDF files from images is very easy with PDFSharp.

For TIFF images, the downside is that the speed is significantly lower compared with the method described in the article Convert Tiff To PDF. I don't have rigorous data, but as an estimation, converting a large image (2.5 MB) takes around 2 seconds. The other method is about 10 times faster, but again it only supports some TIFF files. The performance is not that bad, but if you want to use this code to process multiple files in an application, be sure to do it asyncronously with th UI.

Note: In the download archives I included the PDFSharp library. If you want the latest version, be sure to visit their download page.

History

14 Aug 2008 - first submission of the article.