Re: [Matplotlib-users] alpha-blended legend

[John H. <jdh...@ac...>]

>>>>> "Daniel" == Daniel Newton <da...@ne...> writes:

    Daniel> Hi, I am trying to make a legend transparent (using
    Daniel> GTKAgg) as sometimes it is quite big an obscures part of
    Daniel> my graphs.

    Daniel> I have tryed this with no luck: l = figure.legend(lines,
    Daniel> names, legend) l.set_alpha(.5)

    Daniel> is this possible?

Is it the entire legend you want to make transparent, or simply the
rectangular background?  For the latter, you need to set the alpha on
the legend "frame".  You have two options here

leg = legend(blah, blah)
leg.draw_frame(False)  # turn it off entirely

or 

frame = leg.get_frame()
frame.set_alpha(0.5)   # make it semi-transparent

See http://matplotlib.sf.net/examples/legend_demo.py for an example of
getting handles to all the lines, patches and texts in the legend,
whose properties you can set independently.

There has been a discussion on whether it would be desirable for a set
call on an object to propagate to all the objects it contains.  Ie,
would it be a good thing to be able to do

set(leg, alpha=0.5) 

and have this propogate to the legend frame, lones, patches, and text
instances.  Or is the current setup where you control each of these
objects independently preferable?

JDH