Add support for lineThickness in AddRelTag

[fredde-fisk]

New attempt at #218

[kirchsth]

Hi @fredde-fisk,

thank you for the new skinparam based implementation.

Your solution uses the skinparam arrow Thickness xxx (instead of styles). I checked your implementation and it works basically like below (only that it is documented)

I have only 2 questions:
a) Is Thickness a new skinparam (means do we need a version check and do we have to ignore it in older PlantUML versions)?
b) Can you add $lineThickness as last argument of AddRelTag()... and other calls? It would avoid order/meaning changes in the arguments (if a call uses arguments without keywords)

Thank you and best regards
Helmut

@startuml
!include https://raw.githubusercontent.com/plantuml-stdlib/C4-PlantUML/master/C4_Container.puml

' , $lineThickness=3)
AddRelTag("tag1", $lineStyle=DashedLine())
skinparam arrow<<tag1>> {
     Thickness 3
}

' , $lineThickness=8
AddRelTag("tag2", $lineColor="#800000", $lineStyle=DottedLine())
skinparam arrow<<tag2>> {
     Thickness 8
}

Container(a, "A")
Container(b, "B")
Container(c, "C")

Rel(a, b, " ", $tags="tag1")
Rel(b, c, " ", $tags="tag2")
Rel(a, c, " ")

@enduml

I checked the last non working sample too (and it is working with current version, I didn't check it with an older version)

@startuml
skinparam arrow {
    Color red
    FontColor green
    FontSize 15
}

skinparam arrow<<tag1>> {
        FontColor blue
        Thickness 6
}


skinparam arrow<<tag2>> {
        Color #blue;line.dotted

}

skinparam arrow<<tag3>> {
        FontColor gray
}

[A] -> [B] : hello

[A2] -> [B2] <<tag2>> : hello

[A12] -> [B12] <<tag1>><<tag2>> : hello

[A1] -> [B1] <<tag1>> : hello

[A13] -> [B13] <<tag1>><<tag3>> : hello
[A31] -> [B31] <<tag3>><<tag1>> : hello
@enduml

[kirchsth]

Sorry, I commented it ~50 days ago but it was not visible for you.
I hope it is visible now.
Can you change the argument order?

[kirchsth]

$lineThickness should be last argument in all calls, that existing diagrams have no unexpected side effects if they use unnamed arguments

[kirchsth]

Hi @fredde-fisk,
during my #232 preparation I found a problem if no color is used in combination with $lineThickness.
I reused your branch and fixed it directly in a new PR #254 (and added a new TestRelationsTags.puml). I hope it is ok for you.
BR Helmut