Is it possible to draw standalone arrows with PlantUML?

Question

I'm creating a diagram with different types of arrows (line, dashed, dotted, etc.). But instead of adding a label to each arrow I would like to create a legend where a replica of each arrow type is displayed alongside its meaning.

Is there a way to tell PlantUML to simply draw a small segment of a specific arrow type?

Answer 1

Is there a way to tell PlantUML to simply draw a small segment of a specific arrow type?

Generally speaking, no, especially not in a legend.

However, I can think of a way (it's somewhat complicated). A legend will let you include images, and you can use PlantUML to generate each arrow image.

Here's one example to get a regular arrow (I'm making the classes small and hiding them with some magic):

skinparam style strictuml
scale 0.5
hide empty members
skinparam Class {
    BorderColor transparent
    BackgroundColor transparent
    FontColor transparent
}
class " " as A
class " " as B
A -> B

If you render that, you get a URL of https://www.plantuml.com/plantuml/png/ROpB2i9034Nt-OhWNd7ZLkWK_8yu4tJeF4gIBahntmqAWcWk10udkJhbDfDGHRMri6_9qPPQG2Cv7mydkEV4o7Ms5IlNAuk2Vjx6Gggu0Vg4BebbxAKBcb1JF-5cRqTnkabVMlhlBxtPhtb0VFNlFAGuV6E00VTd34y0 which looks like

Next, you plug that URL into an <img:> tag in a legend of another diagram:

@startuml test
legend
    | <img:https://www.plantuml.com/plantuml/png/ROpB2i9034Nt-OhWNd7ZLkWK_8yu4tJeF4gIBahntmqAWcWk10udkJhbDfDGHRMri6_9qPPQG2Cv7mydkEV4o7Ms5IlNAuk2Vjx6Gggu0Vg4BebbxAKBcb1JF-5cRqTnkabVMlhlBxtPhtb0VFNlFAGuV6E00VTd34y0> | regular arrow |
end legend
@enduml

The result is