When we convert our PlantUML diagrams we get a default look-and-feel for our diagrams that is mostly red and yellow based. We can alter the style and color of individual elements using the skinparam command. But we can also apply so-called themes to our diagram that will alter the look-and-feel of our diagram with a simple theme reference.

We can define the name of the theme in our diagram markup using the !theme directive. Or we can use the command-line option -theme when we generate a diagram from our markup. We can even combine both methods where the end result is also a combination of both themes.

In a previous post we learned how to use the built-in icons from the OpenIconic set. In the newer PlantUML versions several icon sets have been added as standard library. These sets include AWS icons, Font Awesome icons, Devicons and Google Material icons.

To use an icon from the icon set we must include the icon using the !include statement. In our PlantUML definition we reference the icon with the syntax <$iconName>. In the following example PlantUML definition we include 2 icons from the Font Awesome and Devicons icon sets: