How to correct PlantUML Line Path

Question

I created this diagram using the following code. But as you can see, the lines going from (Cancel Order) and (Place Order) to (Publisher) decide to take a terribly rounded p

Answer 1

If anyone wants to know a more specific, put probably much more useless answer, here is what I did in the end.

    order -down- publisher
    publisher -[hidden]up- order

so for some reason adding the duplicated command both ways solves it.

Answer 2

To make a connection less important in the layout, use [norank], e.g., a -[norank]-> b

Answer 3

Try the options suggested by @Peter Uhnak along with linetype :

skinparam linetype polyline
skinparam linetype ortho

Give better options for lines. Using ortho - (Here)

you will get -

Answer 4

There are some tricks that you can try, listed below. The layouting itself is performed by GraphViz (dot layouting iirc), and GraphViz simply does this sometimes. Graph layouting is a NP-complete problem, so algorithms usually take harsh shortcuts.

Typical workarounds that I've seen or used include:

• adding hidden lines a -[hidden]- b
• extending the length of a line a --- b (more dashes, longer line)
• specifying preferred direction of lines (a -left- b)
• swapping association ends (a -- b → b -- a)
• changing the order of definitions (the order does matter... sometimes)
• adding empty nodes with background/border colors set to Transparent

So if you really want to have a nice layout, you'll need to put some elbow grease in, but keep in mind that the layout will be still brittle -- if you add/remove items, you might need to redo it again.