svg exports of diagrams with maxMessageSize/wrapWidth have spacing issues

Question

this issue is related to a C4-stdlib discussion that the spacing is not correct in svg exports.

If I export e.g. following simple sample with skinparam maxMessageSize then all words are separated in the svg export. And if the sample is without then all words a written in one line and the rendering is much cleaner.

@startuml
skinparam arrow {
    FontSize 8
}
skinparam maxMessageSize 250

a -> a : **Perform the usual session auth**

@enduml

I overlaid the 2 exports it in following svg that you can see/compare the differences:


(if you open the image in a new tab and then see the source you will see the code of the generated svg)

The same problem can be reproduced with skinparam wrapWidth 300 too.

@startuml
skinparam arrow {
    FontSize 8
}
skinparam wrapWidth 300
skinparam maxMessageSize 150

rectangle "Perform the usual session auth" as a

a -> a : **Perform the usual session auth**
@enduml

I think one of following solutions could work
a) all words which fit in one line are combined 
b) "x" and "width" looks rounded for me in svg (and y has values like 57.7227) maybe x/width can be written with the same number of decimals 

Thank you and best regards
Helmut

Comments

If rendering hint would be used in PlantUML DriverTextG2d class, like

g2d.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);

then it would creates a text like the line 3.

And the sequence diagram would look like