Work flow for publishing figures under Common Creative license (in order to ease re-use in journal publications) There are already answered questions on academia.SE about the re-use of already published figures. Here, a IMHO quite simple solution was proposed but triggered the question "Why is not everyone doing it?", indicating that there could be drawbacks. In this question, I would like to base on the mentioned solution and ask detailed questions about its feasibility.

Problem

Several journals obligate the authors to sign a copyright transfer agreement. If the authors publish a figure in the scope of this agreement, they are in general (this may depend on the journal's policy) not allowed to re-use the figure elsewhere without permission of the publisher. Therefore, if the authors would like to re-use a figure in another journal article, book, etc., these are the ways to go:


don't care about copyright and publish anyway (could cause serious trouble)
modify the artwork and publish a modified version (a gray area and probably tedious)
check what the publisher's policies are (perfectly legal, but tedious and varies from publisher to publisher)
ask for permission (perfectly legal, but definitely tedious)


Why is the second option a gray area? If I am not mistaken, one still needs the permission of the copyright holder (in this case the publisher) if the artwork is derived from the original. Of course, if the authors want to plot data (copyright does not apply for data), they can chose to use different colors, fonts, line widths, etc. in their figure. But I guess there is no clear statement when an artwork is so different that it is not derived. Additionally, one has to alter the figure every time, which in some cases simply does not make sense. See also the points made here and here (and the references therein).

Solution?

The answer could be quite simple. Publish the figures under a Creative Commons license and use them in your publications along appropriate attributions. So why is not everybody doing it? Are there legal issues? Or is the work flow too complicated? From my point of view it is perfectly legal and requires the least effort (well, apart from the complete disregard of copyright). But let us get down to detail.

Q0: What is meant by figure when I have software code that generates it?

Personally, I often use LaTeX and TikZ to draw figures. In this case, is the figure (i.e., the output of the LaTeX/TikZ code after compiling) subject to copyright or the code itself? Or alternatively, is it sufficient to share the code on a public repository and use the resulting figure in the publications?

Q1: What license is suitable?

A short web search showed that the Creative Commons CC-BY license should be a reasonable choice, as it requires proper attribution but allows re-use under a different license (which I assume will be the case for most journals). Any comments? 

What about the code that generates the figures? I used GPLv2 in most of my projects without giving much thought to it. But technically, I would like to allow the use of the compiled version in commercial journals, so maybe GPLv2 is too restrictive in this case.

Q2: What is the correct attribution in a publication?

As already asked here, what is the correct attribution in the figure caption, assuming that the figures are published on a repository that issues a DOI?

Q3: Is there an existing implementation of such a work flow?

Are there any tools that automate version control of the code that generates the figures, deployment of the results to archives such as figshare or zenodo, keeping track of the deployed versions etc.?
The software used to create a work does not change anything with respect to the its copyright status.  I can create a work in Photoshop and distribute it (the work) under CC-0 if I want.  The fact that someone needs to have a non-free software to open it isn't important. Where things could get tricky for something like a PS file is if each layer has elements that could be considered fair use within the overall final image may be being distributed in full and hence no longer subject to fair use exceptions.  That won't be concern for most LᴬTEX / TikZ stuff

You seem to be talking only about the final version of figures, so CC-BY should be fine.  If you want to release the LᴬTEX / TikZ code, it seems that Creative Commons is indeed the preferred license type in the community (see TeXample.net which requires user to submit their TikZ stuff as CC-licensed works).  If the code is GPLv2, though, the visual result isn't covered by GPLv2.

The correct attribution will depend on your style guide.  I don't think you would go wrong to follow whatever standard it uses for works of art unless there is a more specific format in your style guide.

I'm not aware of any workflows to do this, but they shouldn't be too hard to write if you're using that many figures that it's worth your time.