Legend tuple handler improve

[jmehne]

Continuation of #2904 and #2034.

Rebased, added some more documentation and adapted the example a bit.

I'm not sure how to ceate the test image. I created it on Ubuntu 14.04. which uses version 2.5.2 of the Freetype library - do I need to compile+install 2.5.3, or even the exact, possibly patched Fedora version that was used to create the rest of the images?

[jmehne]

Eh, sry, I screwed up with the initial push. Hopefully it's okay now.

[tacaswell]

👍 awesome

attn @mdboom re question about freetype.

[QuLogic]

To create consistent text output, you need to set local_freetype = True in setup.cfg before building to use a specific version of FreeType instead of the system one.

[mdboom]

@QuLogic is exactly right about freetype here. This is new since 1.5.x, so is documented in the "devdocs", not the default doc version, here:

http://matplotlib.org/devdocs/devel/testing.html#building-matplotlib-for-image-comparison-tests

[jmehne]

Okay, I've recreated the test with the built-in FreeType version.

[tacaswell]

'power cycling' this PR to make it rebuild against current master.

[jmehne]

Rebased. Last time a Python 2.7 test failed that seemed unrelated to me (matplotlib.tests.test_mathtext.test_mathfont_stix_07.test). Let's see if that is still the case.

[tacaswell]

Can we use None as the sentinel value?

[jmehne]

Sure.

[WeatherGod]

I think this needs a whats_new entry?

[jmehne]

I put a description in doc/users/whats_new/multiple_legend_keys.rst. Is that enough?

Edit: sry, I was in a hurry. What I meant to say: @WeatherGod did you notice the description in doc/users/whats_new/multiple_legend_keys.rst?

If not, is that what you had in mind?
If so, what exactly are you missing compared to that description? :)

[tacaswell]

@Three-Comrades Yes, that looks sufficient to me.

[tacaswell]

👍 from me, but I will refrain from pushing the green button because I have commits in this PR.