In a previous post I looked at why you might want to convert a PDF file to an image (you can use JPedal to do this). This time I will look at doing the opposite, and explain why and how to convert an image to a PDF file.
Why convert image to PDF?
Some images can be displayed in the browser, and do not require PDF display tools to be viewed. Converting images to PDF files allows the display of Tiff and other non-support image types and makes them easier to handle. PDF files can be altered and extra content can be added to them. Converting an image to a PDF will also reduce the size of the file.
The PDF file format is very complex and we generally recommend using existing tools rather than trying to build your own from scratch (if you really want to try this we have a series of articles on how to do this). We recommend you use a Java library. There are lots of Open Source and Commercial Java libraries and we have 2 examples below.
1. iText (Open source library)
One way to convert an image to a PDF in Java is to use iText. iText is a PDF generation and manipulation tool for Java. It allows you to create a new PDF document and then add an existing image to that document.
You can find example code for adding an image to a PDF document using iText here.
2. JDeli (Commercial library)
Another way to convert an image to a PDF in Java is to use JDeli, our Java image library. JDeli can be used to read and write a large number of image file formats in Java. It can also be used to write an image to a PDF file.
Below is some example code to convert an image to a PDF using JDeli:
//create the image file File imageFile = new File("C:\\path\\to\\image\\exampleImage.png"); //create a new PDF file File pdfFile = new File("C:\\path\\to\\pdf\\examplePDF.pdf"); pdfFile.createNewFile(); //write the image to the pdf PdfEncoder encoder = new PdfEncoder(); encoder.write(imageFile, pdfFile);
Alternatively, you can pass in a BufferedImage instead of a File to the write method. If the image is a multi-page TIFF then JDeli will generate a multi-page PDF file, with as many images as the TIFF contains.
Why use JDeli?
JDeli offers a range of advantages over ImageIO and alternatives, including:
- prevents heap related JVM crashes
- implements unsupported image formats
- reduce output file size
- improve read/write performance
- supports threading
- superior image scaling algorithms
If you found this guide useful, you may be interested in our series of articles on handling common image file formats in Java.
IDRsolutions develop a Java PDF library, a PDF forms to HTML5 converter, a PDF to HTML5 or SVG converter and a Java Image Library that doubles as an ImageIO replacement. On the blog our team post about anything interesting they learn about.