PDF files are the world’s most common file format, defining 70% of the world’s documents. But they are also complex and poorly supported by Java.
As I have spent over 20 years working with Java and PDF files, I thought a useful contribution to the excellent new foojay.io (a place for friends of OpenJDK), where you are reading this now, would be a quick guide for Java Developers!M. Stephens
Unless you are creating all your images, by drawing then inside the code with the Graphics2D commands, you will need an image library to load images as BufferedImages. You will also need an Image library if you wish to save the results.
ImageIO is part of Java, it is free and it supports a range of Image formats including GIF, JPEG, PNG, and TIF. Because it is expandable, there are additional libraries to extend it.M. Stephens
BufferedImage is one of the most useful Java abstractions. It hides all the complexity of different types of images whilst allowing access to the underlying data. Under the hood, a BufferedImage can be many types of image.
Java includes support to load and save images in various formats using ImageIO, and other libraries such as Apache Imaging and our JDeli library also offer this feature.
Next time we will talk more about ImageIO and other Image libraries.M. Stephens
There are lots of different ways of describing Color. As developers, we are most familiar with the RGB model, where every color is defined by mixing Red, Green and Blue together. In the print world, CMYK is very common, where colors or printed by literally mixing different amounts of Cyan, Magenta, Yellow and Key (black). You may also come across other ways of describing color such as DeviceN. There are also lots of different versions of RGB.
Next time we will talk more about BufferedImages.M. Stephens
Java makes images simple to use. You can work with a BufferedImage and just load or save this to any supported image file format. A BufferedImage includes lots of functionality which allows you to render and process the image, with all the complexity and implementation hidden by Java. A BufferedImage can even be used as a Graphics2D canvas which can be drawn on. Here is some example code.
While Java removes a lot of Image complexity, it is worth understanding in more detail how images work. In this series of articles, we will be diving deep into how BufferedImage provides this abstraction, how different types of images work and how you can access the low-level Image data.M. Stephens