How can I get a list of all possible skinparam settings? (Use case: increase participant box padding)

Question

I would like to increase the interior padding of a box that is used to group participants together, as in the following example:

participant Hamlet
box "Royalty"
  participant Laertes
  participant Claudius
end box

Hamlet   -> Laertes  : Stab
Hamlet   <- Laertes  : Confess
Laertes  -> Laertes  : Die
Hamlet   -> Claudius : Accuse
Hamlet   -> Claudius : Stab
Claudius -> Claudius : Die

When I render the above diagram, the resulting image has the self-referential flows is very close to the border of the box that surrounds the second two participants:

I would prefer that the box that groups participants have a larger interior padding so that the two lines are more distinct.

I was hoping to find a skinparam that would control this setting, so my more general question is, how can I get a list of all skinparams supported by a particular skin (or by all skins)? I'm guessing that if I could do this, I could discover the answer to many general questions like the one posed above.

Thanks for the help!

Answer 1

I discovered this snippet in http://plantuml.sourceforge.net/skinparam.html:

Since the documentation is not always up to date, you can have the complete list of parameters using this command:

java -jar plantuml.jar -language

That answers my original question exactly! Unfortunately, it doesn't solve my box interior padding case, as these appear to be the only SequenceBox* parameters:

SequenceBoxBackgroundColor
SequenceBoxBorderColor
SequenceBoxFontColor
SequenceBoxFontName
SequenceBoxFontSize
SequenceBoxFontStyle

Oh, well, I'll just live with the default look until I find some other way.  :)

Answer 2

Here's the source code that contains some of the info you want (though not easy to see right away): http://grepcode.com/file/repo1.maven.org/maven2/net.sourceforge.plantuml/plantuml/7959/net/sourceforge/plantuml/SkinParam.java?av=h#SkinParam

Googling the parameter names with plantuml sometimes finds discussions to explain more. Good luck.