Display comma instead of dot at contour levels?

Hello everyone,

the title is basically my whole question. I want to change the labels on the contour levels of a contour plot so that the numbers have a comma instead of a dot (its a german thing).

I've read that following code would have worked in older versions of Matlab - C and h being the outputs of the contour function:

acl=clabel(C,h,'FontSize',10,'Color','k');
for i=1:length(acl) 
oldlabel=get(acl(i), 'String'); 
newlabel=strrep(oldlabel, '.', ','); 
set(hcl(i),'String',newlabel); 
end

In the Matlab version I'm using, clabel is returning a "GraphicsPlaceholder"-Object, which I cannot change in the same way. How would I change the labels in Matlab version R2017a ?

(Same question has been posted here in german)

Answer 1

[Walter Roberson]

Yair recently posted some details on customizing contour lines and labels. See https://undocumentedmatlab.com/blog/customizing-contour-plots-part2

[Ingo Rück]

Thanks, this helped me to understand the new contour-Object better.

However I ran into a different problem. If I understand the blogpost correctly, the TextList property is where I want to apply the change. This property is a double array, which cannot contain strings. If it was a cell array, I could just swap the dot for a comma and update the h.TextList property with the new cell array.

As is, I still dont know if there is a way to do this.

[Walter Roberson]

Supposing that the contour object has been stored in hContour, then:

contour_label_objects = hContour.TextPrims;
for thislabel = contour_label_objects
  thislabel.String = strrep(thislabel.String, '.', ',');
end

[Ingo Rück]

Thank very much, that worked. Is this the only way to change the dot to comma? Because now it changes back to dots, whenever I change the size of the axes. There must be a way to change the contour labels that get created whenever the axes changes in size..

[Yair Altman]

as noted in my blog post, you need to trap the axes' MarkedClean event in order to reapply your customizations, because whenever the axes are repainted Matlab resets the axes and contents to their uncustomized format. See my blog post for details.

[Walter Roberson]

Thanks, Yair.

[Ingo Rück]

Thank you very much, this turned out a lot more complicated than I thought it would!