PlantUML is an open source tool where you can specify your UML diagrams in a text format, which looks quite similar to a simple programming language. It is often used by software developers and enables users with accessibility needs to draw UML diagrams.
Although there are other text formats for UML modelling, Plant UML is one of the most popular formats: It supports many diagram types, automatically lays out your diagram elements, and has a simple, human-readable language.
PlantUML uses the Graphviz software to layout your diagram where the layout algorithm aims connectors in the same direction (top to bottom, or left to right) and attempts to avoid crossed or connectors to make the diagram more readable. Graphviz DOT code can also be used to create flow charts, graphs and more.
draw.io allows you to insert PlantUML and Graphviz DOT code and automatically adds an image with your diagram to the drawing area.
Insert a PlantUML diagram in draw.io
- Open a draw.io diagram or create a new blank diagram, and select Arrange > Insert > Advanced > PlantUML from the menu.
- Paste your PlantUML code into the dialog and click Insert.
By default, your UML diagram will be inserted as SVG on a transparent background. This is easily resizable and movable, like all other draw.io shapes.