GitLab Flavoured Markdown: render UML diagrams by adding 'Syntax Highlightning' for PlantUML #9550

janklostermann opened this Issue Aug 10, 2015 · 15 comments


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there is syntax highlightning for some languages (Ruby, Python, etc.) using


(using apostrophes for the backticks here)


to add PlantUML to the languages
to gain:
for code fencing
-> with the difference that the output is not a beautified code, but a UML diagram. The PlantUML text ( is replaced by the UML diagram's graphic.

expected result

getting the power of UML inside the markdown documents without the cost of unmaintainable inserted graphics


replacing the pygments highlightner by the PlantUML renderer in case of 'plantuml' as language

Razer6 commented Sep 4, 2015

You may want to raise a feature request at, which is the used syntax highlighter.

@Razer6 Razer6 closed this Sep 4, 2015

@Razer6 : I do not believe, that Rouge will feel responsible for this, as syntax highlighning is something very different to interpreting it.
They might be interested in syntax highlight the Plant-UML text, but not in the conversion into a graphic.
Furthermore it would probably spoil their interface, that for syntax highlighning just needs to return text... (not a graphics file)

Therefore I would suggest a switch at the point where you (Gitlab) invoke rouge. For some specific languages like PlantUML (or Graphviz, etc.), which are textual markup for graphics, the respective markup-interpreter could be invoked and return the graphic to be displayed.

There could be even a further parameter to the interpreter, in case of Plantuml: png, svg, text (default (without that parameter) would be png). E.g.

''' plantuml svg   



with ''' replaced with 3 back-ticks, to get the graphic returned as svg.

Therefore I would like to ask you to reopen this issue again. Thanks for considering it.

Razer6 commented Sep 6, 2015

I see what you mean. Interesting feature request, you may want to raise one at


Cool. Thank you!


Von unterwegs gesendet. Sent from my phone. 

-------- Ursprüngliche Nachricht --------
Von: Joan Queralt
Datum:06.09.2015 17:47 (GMT+01:00)
An: gitlabhq/gitlabhq
Cc: janklostermann
Betreff: Re: [gitlabhq] GitLab Flavoured Markdown: render UML diagrams by
adding 'Syntax Highlightning' for PlantUML (#9550)

It's already there, I added it a few days ago:

Thank you.

Reply to this email directly or view it on GitHub.



Would be very nice!


That would be one of the most valued features for development workflow.

vazyzy commented Mar 28, 2016



Why closed, could you tell me? @janklostermann


GitLab did not feel responsible, then saw the point. Someone else then
created the feature request, suggested by the GitLab team. I checked on
this one about a week ago, but could not find it anymore. So I do not
know, what the current status is. :-(

Just have a look at the issue's thread, there you can see what happened...

Am 2016-05-11 um 07:40 schrieb wangyifan:

Why closed, could you tell me? @janklostermann

You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
#9550 (comment)

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thalesfsp commented Feb 2, 2017 edited

Do we have updates on this topic?

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