Colors

You can use specify fill and line colors either:

with its standard name
using HEX value #AABBCC
using short HEX value #ABC

@startgantt
[Activity1] lasts 5 days
[Activity2] lasts 5 days
[Activity1] is colored in White/Red
[Activity2] is colored in Silver/SeaGreen
[Activity1] -> [Activity2]
@endgantt

Example Sequence Diagram:

@startuml
actor Bob #Red/Yellow
actor Alice #FF0000/FFFF00
Alice -> Bob : hello
@enduml

Also see: skinparam

Automatic color

The special value automatic can be used for text. In that case, the color is either black or white, depending on the current background.

@startuml
skinparam classFontColor automatic
skinparam classHeaderBackgroundColor #444

class classA {
testMethodCode()        
}

class classB #fff {
testMethodCode()       
}
@enduml

View colors in PlantUML

A user has recently created an image to display all names colors used by PlantUML. (We thank him by the way!)

So a new feature has been added to print all those colors using a special diagram description:

@startuml
colors
@enduml

It is also possible to print a palette of colors close to some other color (using its name or HEX value).

@startuml
colors chocolate
@enduml