6. Layout

Tip

It’s true that when diagram is big (or very big) manual placement could be useful. However and unfortunately, this is against PlantUML concept https://forum.plantuml.net/977

Wrangling diagram elements to an exact position or layout is not what PlantUML is for.

However, there are some layout tweak mechanisms that should be used sparingly. These are described here.

6.1. Arrows for Layout

We can specify a connection direction as follows and this affects the diagram layout:

Arrow Syntax

Text

Direction

->

horizontal left to right

-->

vertical top to bottom

-up-> or -u->

vertical bottom to top

-down-> or -d->

vertical top to bottom

-left-> or -l->

horizontal right to left

-right-> or -r->

horizontal left to right

--norank]>

make a connection less important

--[hidden]>

hidden

-[hidden]d->

hidden with direction e.g. down

---> or ----> or -----> …

varying arrow lengths; add dashes to make line longer

Tip

The order in which diagram elements are defined can also impact how they are laid out.

Tip

Arrow head stypes per https://plantuml.com/sequence-diagram are for sequence diagrams only i.e. won’t work in our component diagram examples.

6.2. up down left right

@startuml rectangle Arrows rectangle Up rectangle Down rectangle Left rectangle Right Arrows -u-> Up Arrows -d-> Down Arrows -l-> Left Arrows -r-> Right @enduml 

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@startuml

rectangle Arrows
rectangle Up
rectangle Down
rectangle Left
rectangle Right

Arrows -u-> Up 
Arrows -d-> Down
Arrows -l-> Left
Arrows -r-> Right

@enduml

6.3. left to right direction

@startuml left to right direction 'top to bottom direction rectangle Arrows rectangle A rectangle B rectangle C rectangle D rectangle E rectangle F Arrows --> A Arrows --> B Arrows --> C Arrows --> D Arrows --[hidden]> E @enduml 

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@startuml

left to right direction
'top to bottom direction

rectangle Arrows
rectangle A
rectangle B
rectangle C
rectangle D
rectangle E
rectangle F

Arrows --> A 
Arrows --> B
Arrows --> C
Arrows --> D
Arrows --[hidden]> E

@enduml

6.4. top to bottom direction

@startuml 'left to right direction top to bottom direction rectangle Arrows rectangle A rectangle B rectangle C rectangle D rectangle E rectangle F Arrows --> A Arrows --> B Arrows --> C Arrows --> D Arrows --[hidden]> E @enduml 

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@startuml

'left to right direction
top to bottom direction

rectangle Arrows
rectangle A
rectangle B
rectangle C
rectangle D
rectangle E
rectangle F

Arrows --> A 
Arrows --> B
Arrows --> C
Arrows --> D
Arrows --[hidden]> E

@enduml

6.5. hidden

Note

Note that the location of E is determined by a hidden arrow. Whereas F is floating i.e. not connected by an arrow so it can go anywhere.

6.6. nodesep and ranksep

@startuml 'skinparam nodesep 10 'skinparam ranksep 20 rectangle Arrows rectangle A rectangle B rectangle C rectangle D rectangle E rectangle F Arrows -[bold]-> A Arrows -[#pink,dashed,thickness=10]-> B Arrows -[#4567ff,dotted]-> C Arrows --> D E ---> C @enduml 

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@startuml

'skinparam nodesep 10
'skinparam ranksep 20

rectangle Arrows
rectangle A
rectangle B
rectangle C
rectangle D
rectangle E
rectangle F

Arrows -[bold]-> A 
Arrows -[#pink,dashed,thickness=10]-> B
Arrows -[#4567ff,dotted]-> C
Arrows --> D
E ---> C

@enduml

@startuml skinparam nodesep 5 'skinparam ranksep 20 rectangle Arrows rectangle A rectangle B rectangle C rectangle D rectangle E rectangle F Arrows -[bold]-> A Arrows -[#pink,dashed,thickness=10]-> B Arrows -[#4567ff,dotted]-> C Arrows --> D E ---> C @enduml 

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@startuml

skinparam nodesep 5
'skinparam ranksep 20

rectangle Arrows
rectangle A
rectangle B
rectangle C
rectangle D
rectangle E
rectangle F

Arrows -[bold]-> A 
Arrows -[#pink,dashed,thickness=10]-> B
Arrows -[#4567ff,dotted]-> C
Arrows --> D
E ---> C

@enduml

@startuml 'left to right direction 'top to bottom direction 'skinparam nodesep 10 skinparam ranksep 150 rectangle Arrows rectangle A rectangle B rectangle C rectangle D rectangle E rectangle F Arrows -[bold]-> A Arrows -[#pink,dashed,thickness=10]-> B Arrows -[#4567ff,dotted]-> C Arrows --> D 'long arrow for no good reason E ---> C @enduml 

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@startuml

'left to right direction
'top to bottom direction

'skinparam nodesep 10
skinparam ranksep 150

rectangle Arrows
rectangle A
rectangle B
rectangle C
rectangle D
rectangle E
rectangle F

Arrows -[bold]-> A 
Arrows -[#pink,dashed,thickness=10]-> B
Arrows -[#4567ff,dotted]-> C
Arrows --> D

'long arrow for no good reason 
E ---> C 

@enduml

6.7. together

D,E are forced together.

E-C is specified as a very long arrow

@startuml rectangle Arrows rectangle A rectangle B rectangle C together { rectangle D rectangle E } rectangle F Arrows -[bold]-> A Arrows -[#4567ff,dotted]-> C Arrows -[#pink,dashed,thickness=10]-> B Arrows --> D E ---------> C @enduml 

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@startuml

rectangle Arrows
rectangle A
rectangle B
rectangle C
together {
rectangle D
rectangle E
}
rectangle F


Arrows -[bold]-> A 
Arrows -[#4567ff,dotted]-> C
Arrows -[#pink,dashed,thickness=10]-> B
Arrows --> D
E ---------> C

@enduml

6.8. linetype polyline ortho

Either of the following can be added to a diagram:

  • “skinparam linetype polyline”

  • “skinparam linetype ortho”

See Create Real Life AWS Diagrams for practical examples of where these are used.

As at May 2020, it looks like there can be an issue using ortho. Specifically the label being too distant from the line.