PlantUML¶
PlantUML is a tool to generate diagrams from textual source code. It can be used to generate UML-compliant diagrams, hence the name. Many non-UML diagrams are also supported making it a very versatile tool.
PlantUML is actually a “drawing tool”, meaning it can do more than only UML diagrams. It will allow you to “draw” diagrams that are not legal UML.
Two short examples of PlantUML diagrams are shown below. The specification of the language can be found at http://plantuml.com/ with plenty of examples.