PlantUML follows the web colors, which incorporate a subset of X11 color names. The X11 colors are especially useful to visualize color ranges.
Here are some tables of X11 color names based on the X11
rgb.txt
. If a white bar appears next to the attribute
PUML, the color name is not supported in PlantUML
(e.g. NavyBlue).
When in doubt, use the hexadecimal color code.