How to make PlantUML left/right/up/down arrow longer

Question

The syntax for switching the directionality of the arrows in PlantUML is clear. One can use an -left->, -right->, -up->, -down-> to achieve left, right, up, and down directionality respectively. The documentation is equally clear that increasing the length of an arrow on rendering can be done syntactically through increasing the number of dashed in the arrow in the UML code (eg. --> is increased to ---> or ---->).

This doesn't seem to work (at least in the Visual Studio Code extension by Jebbs) when there is also directionality included. So, for example, -left---> does not increase the length of the arrow. Is this expected behavior?

Eldrida

A workaround is to add a blank label with some number of spaces A -left-> B : " " – Hysterics

Answer 1

Using the latest online server, this code doesn't produce consistent results (it only works for up and down). Seems like a bug.

@startuml
skinparam style strictuml
hide empty methods
hide empty members

A -r-> B
A1 --r--> B1

C -l-> D
C1 -l--> D1

E -u-> F
E1 -u--> F1

G -d-> H
G1 -d--> H1

@enduml

EDIT: adding skinparam nodesep 50 (the number increases horizontal separation for all classes) is a possible work-around to this bug.

Hysterics

Answer 2

I've found you can control the length of the lines is via a blank label on the association:

Foo -r-> Bar : " "

or

Foo -u-> Bar : "\n\n\n\n"

Libre

A shady workaround, but it works :D – Averse