This function uses plot and text commands provided by matlab to draw a very flexible legend. Now you can draw a legend in your own way. If you need, you can write more sophisticated functions based on this, which would be more personalized.
qian (2020). freelegend(hline,hax,hf,str,posi,varargin) (https://www.mathworks.com/matlabcentral/fileexchange/52835-freelegend-hline-hax-hf-str-posi-varargin), MATLAB Central File Exchange. Retrieved .
Inspired by: simonhenin/columnlegend