Org Babel ignores `org-plantuml-executable-args`

Question

I cannot make plantuml set the UTF-8 charset, I've set

'(org-plantuml-executable-args '("-headless -charset UTF-8"))

in the init.el, but when I check in the message buffer the command invoked, these options are missing

java -jar /path/to/plantuml.jar -tsvg -p < /path/to/org-babel-temp-file > /path/to/file.svg

Any clue?

Thanks in advance.

Answer 1

Do C-h v org-plantuml-exec-mode to see its doc string:

org-plantuml-exec-mode is a variable defined in ‘ob-plantuml.el’.

Its value is ‘jar’

Method to use for PlantUML diagram generation. ‘jar’ means to use java together with the JAR. The JAR can be configured via ‘org-plantuml-jar-path’.

‘plantuml’ means to use the PlantUML executable. The executable can be configured via ‘org-plantuml-executable-path’. You can also configure extra arguments via ‘org-plantuml-executable-args’.

It is probably set to jar, the default, but org-plantuml-executable-args only applies when it is set to plantuml, i.e. when using the plantuml executable.

I looked around a bit to find a plantuml executable which must have existed at some point, but AFAICT no longer does. And the jar method in ob-plantuml.el does not allow for arguments (this is probably an omission that is worth a bug report).

SUGGESTION: I think the easiest thing to do is create your own plantuml executable as a shell script and change org-plantuml-exec-mode to plantuml. Something like this (but note it's very lightly tested):

#! /bin/bash

java -jar /path/to/plantuml.jar "${@}"

Put it into some directory, make it executable and then add something like this to your init file:

(setq org-plantuml-exec-mode 'plantuml)
(setq org-plantuml-executable-path "/path/to/script/above/plantuml")
(setq org-plantuml-executable-args '("-headless" "-charset UTF-8"))

Very lightly tested.