One of the really cool features about PDF files is that they are not a boring, static file format – they can interact with the user and the display can change. One of my favourite interactive features is Layers.
You can think of Layers as a separate overlaid page on which text or images can be added. The Layer can have a name and the user (or the PDF itself) can alter whether this Layer is visible or not.
A more practical example is to allow additional information to be included on plans, diagrams or maps
And we can see just the detail we want with a couple of clicks…
Layers are also useful as we can display different things in a printout compared with onscreen display.
So Layers offer a very powerful and user-friendly way to enhance your PDF files for useful purposes or just for fun. If you have seen any really interesting uses of Layers, why not drop me an email or post the link here.
This post is part of our “Understanding the PDF File Format” series. In each article, we aim to take a specific PDF feature and explain it in simple terms. If you wish to learn more about PDF, we have many years worth of PDF knowledge and tips, so click here to visit our series index!
Do you need to write or read JPEG in Java?
We have an easy guide on how to write JPEG in Java using ImageIO and JDeli.
You can learn how to read/write most of the image files in ImageIO. However, it gives little control over the process.
JDeli is easy to use and offers complete support, so why don't you give a try?