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Common legend for multiple histograms in subplots

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I'm trying to display multiple histograms on several subplots (to avoid them overlapping too much), but I'd like to have only one legend for all of them.
I am aware of that post: Unfortunately, that solution doesn't work when you plot histograms instead of plots. Here is the exact same code as proposed as a solution in the previously mentioned post, but with histograms instead of plots:
% Construct a figure with subplots and data
line1 = histogram(rand(1,1000));
title('Axes 1');
line2 = histogram(rand(1,1000));
title('Axes 2');
line3 = histogram(rand(1,1000));
title('Axes 3');
line4 = histogram(rand(1,1000));
title('Axes 4');
% Construct a Legend with the data from the sub-plots
hL = legend([line1,line2,line3,line4],{'Data Axes 1','Data Axes 2','Data Axes 3','Data Axes 4'});
% Programatically move the Legend
newPosition = [0.4 0.4 0.2 0.2];
newUnits = 'normalized';
set(hL,'Position', newPosition,'Units', newUnits);
The legend is set, but we cannot see the colors of the histograms in the legend except for the first one.
I looked for a while for a solution, but haven't found one yet.
Does anybody know how to do that?
Thank you

Answers (1)

Thorsten on 9 Aug 2018
Set the FaceColor explicitly before calling legend:
set(line1, 'FaceColor', 'r')
set(line2, 'FaceColor', 'g')
set(line3, 'FaceColor', 'b')
set(line4, 'FaceColor', 'm')
hL = legend([line1,line2,line3,line4],{'Data Axes 1','Data Axes 2','Data Axes 3','Data Axes 4'});
Laurent Chauvin
Laurent Chauvin on 9 Aug 2018
Edited: Laurent Chauvin on 9 Aug 2018
I'm sorry, what I meant by 'I cannot see the colors of the histograms' is that I cannot see them "in the legend". The histograms itself are properly colored. I guess your fix was to color histogram themselves, and not their rectangles in the legend.
However, I noticed this Warning / Error:
Warning: Error creating or updating Quadrilateral Error in value of property ColorData Array is wrong shape or size
So I think that's the reason why it cannot creates the small rectangles with the histogram colors in the legend, but I have no clue why I get this error.
Laurent Chauvin
Laurent Chauvin on 10 Aug 2018
Hum okay. I'm not sure to understand what is going on, but before I was calling 'legend' at the end of my script to create my histograms, and it wasn't working. However, now I removed it, and I use the 'legend' command when my script is done and has generated the histograms and it works.
Could this be a multithread issue (like legend is called before all my graphs are done, thus creating an issue) ?

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