update tool tip data using data cursor in loop

Hi all.

I am plotting sevrals of plots all in one figure. I want to use custom tool tip that shows me each plot iteration origin.

but for some reason, when using the tool tip , it shows only the last iteration number on all of the plots.

my code bellow.

what am I dong wrong?

fig=figure;
hold on;
for i=1:4
    x=sort(rand(1,100));
    y=sin(2*pi*x*i);
    txt = ['itr ',num2str(i)];
    plot(x,y,'DisplayName',txt)
    dcm_obj = datacursormode(fig);
    set(dcm_obj,'UpdateFcn',{@myupdatefcn,'itr=',i})
        
end
xlabel('x');ylabel('y');
hold off
legend show


function txt = myupdatefcn(~,event_obj,txt4update,Num)
% Customizes text of data tips
pos = get(event_obj,'Position');
I = get(event_obj, 'DataIndex');
txt = {[txt4update ,': ',num2str(Num)],...
    ['x: ',num2str(pos(1))],...
    ['y: ',num2str(pos(2))]};
end

[Adam]

You are overwriting the UpdateFcn callback function each time round the loop so at the end it will take on the value of the last time round the loop. If you want it to show you a history you will need to store up that history in a variable and pass the whole variable to the UpdateFcn at the end. This can be outside the loop as setting UpdateFcn in a loop is not useful.

I'm not 100% sure what kind of end result you are looking for or what your set of plots looks like at the end.

Answer 1

[nirit]

Found a solution!!

fig=figure;
hold on;
 
for i=1:4
    x=sort(rand(1,100));
    y=sin(2*pi*x*i);
    txt = ['itr ',num2str(i)];
    plot(x,y,'DisplayName',txt)
    dcm_obj =datacursormode(fig);
    set(dcm_obj,'UpdateFcn',{@myupdatefcn,'itr='})
      
end
xlabel('x');ylabel('y');
hold off
legend show

function txt = myupdatefcn(~,event_obj,txt4update)
% Customizes text of data tips
pos = get(event_obj,'Position');
txt = {[txt4update ,': ', event_obj.Target.DisplayName],...
    ['x: ',num2str(pos(1))],...
    ['y: ',num2str(pos(2))]};
end