How to update the position of legend with 'Best' Location?

Hi,

I have an output function which I use with fmincon to plot some of variables during optimization process. I use

legend(...,'Location', 'Best')

to define the legend, and in the first iteration it looks really okay. However, as the optimization goes, I update my graph with:

set(h, 'YData', new_data);

And sometimes the legend overlaps with the new plot (it doesn't reposition to adjust for new data). Is there any way I could reposition automatically my legend (I guess apart from deleting it and constructing again every iteration)?

Cheers, Aleksander

[dpb]

I think that's it; the position only gets updated on creation of the label itself, not on any modification of the underlying plot data. The facility would be a reasonable enhancement request it would seem.

ADDENDUM I've not tested it so don't know if it would work or not (and may be either slower or more distractive than simply the delete/recreate option) but the only additional thought I've had would be to set the 'location' parameter to a fixed position and then back to 'best'. I sorta' doubt it'll retrigger the logic to decide location, but it may be worth a try just to see...

[Aleksander Marek]

Yesterday, I tried updating the legend's position with:

set(leg, 'Location', 'North')
set(leg, 'Location', 'Best')
drawnow

But the legend wouldn't move at all

[dpb]

That's actually what I expected; legend is just an m-file and set on the properties after the fact only changes that string recorded in the 'location' property; it doesn't trigger any callbacks or such.

You'd have to use a callback function when data are updated and that's more trouble than simply re-issuing the legend command each iteration.

While no doubt it's not as neat in appearance, if the redrawing is distracting during the simulation, you could place the legend outside the axes so it won't occlude the data and then try the 'best' location at the end for final viewing.

Answer 1

[Massimo Zanetti]

At every new plot reissue the command

legend(...,'Location', 'Best')

So that Matlab recomputes the right position to place it.