You're right: multi-column legends aren't implemented.
There have been a number of points raised lately around the layout of
legends (such as baseline alignment), that are starting to add up to a
push for a (partial) rewrite of the legend code. Unfortunately, I don't
think anyone has stepped up with time available to work on it. But I
think this should go on the list of things to consider, assuming we can
come up with a nice clean interface to present to the user. It would be
helpful to collect use cases for that. For example, would an option
"numcols" be enough (and the legend would just layout the text in that
number of columns), or would you want/need more control over where
individual elements are placed?
Of course, we're always looking for new developers, and if you have the
motivation to work on this, I'm sure the various people on this list
would be happy to help you work through it.
Jose Gómez-Dans wrote:
> About a year ago, Jouni Seppänen indicated how to put a number of patches in a
> legend. So far so good. Now, it turns out that I do have quite a lot of
> patches to throw into this legend, and it would be nice, rather than to have
> a single column, to have the possibility to arrange these patches (and
> associated labels) into columns. I have looked at the legend object, but
> there is nothing suggesting that things can be shuffled around within the
> legend box itself, some sort of "subplot()" for the legend patches. Am I
> correct in assuming this doesn't exist (yet!). I am running 0.91.2, maybe
> it's already been implemented, but I thought I'd ask!
Science Software Branch
Operations and Engineering Division
Space Telescope Science Institute
Operated by AURA for NASA