legend properties of columnlegend

Hi :)

I would like to use columnlegend to make my legend appear nicely. Since I need to change the fontsize and -weight, I used the following code:

h = columnlegend(2, p2,  'location', 'southoutside');
h.FontSize = 16;
h.FontWeight = 'bold'
h

where p2 contains the strings for the legend.

when I look at the properties of h, they changed to the desired values, but they do not change in the plot.

The same happens, when I enter it directly to the legend command:

h = columnlegend(2, p2,  'location', 'southoutside','FontSize',16,'FontWeight','bold');

The image shows my problem. I am using R2016b.

Does someone know how to solve this?

Answer 1

[Adam Danz]

The problem

The file exchange function columnlegend() (started in 04/2010, last updated 09/2016) calls legend() with multiple outputs,

[legend_h,object_h,plot_h,text_strings] = legend(str);

Starting in R2024b, calling legend with multiple outputs will throw a warning.

As is noted in the r2016a documentation of legend(),

Note:   This syntax is not recommended and creates a legend that does not support 
all graphics features. Use the l = legend(__) syntax to return the legend object 
and set Legend Properties instead.

Toward the top of Matlab's legend code, a flag named version is set to on when the number of output arguments is greater than one. When version is on, a legacy version of the legend is created by this function which we do not have access to

leg.doPostSetup(version_flag);

Solution

Starting in r2018a, you can set the NumColumns property of Matlab's legend() function making the columnlegend() function obsolete (thanks to the original author, Simon Henin, for inspiring that change in Matlab).

legend(. . ., 'NumColumns', 2)

For Matlab releases prior to r2018a, use the 2nd output of columnlegend(), isolate the legend string handles, and change the text properties.

[h, object_h] = columnlegend(. . .);

% Set spacing (This will not change font size or weight)
set(h, 'FontSize', 16, 'FontWeight', 'bold')

% Get text handles 
legTextHand = object_h(strcmpi(get(object_h,'type'),'text')); 
% Change fontsize and weight
set(legTextHand,'FontSize',16,'FontWeight','bold')

[Anna S]

I have also tried something similar, but your solution works!

Thank you a lot!

Funnyly, I need to give the information twice to get it work:

[h,object_h] = columnlegend(2, p2,  'location', 'southoutside');
h.FontSize = 16;
h.FontWeight = 'bold'
% Get text handles 
legTextHand = object_h(strcmpi(get(object_h,'type'),'text')); 
set(legTextHand,'FontSize',16,'FontWeight','bold')

But at least it does what it should :)))

[Adam Danz]

Ah.... this section below sets the spacing

h.FontSize = 16;
h.FontWeight = 'bold'

while this section below sets the fontsize etc.

set(legTextHand,'FontSize',16,'FontWeight','bold')

Glad I could help.

[Afiq Azaibi]

Starting in R2024b, calling legend with multiple outputs will throw a warning. It will continue to function as it has previously. This will mean that the use of the file exchange function columnlegend() will begin to warn in R2024b