MATLAB: Using gcf in functions

figure handlesfunctionsgcfMATLAB

I make plots in the main part of my scripts but I also do plotting from functions. It appears that when I call a function, gcf does not have to be passed as an argument, i.e., it appears as though gcf is some sort of global variable. I say "appears" because some times gcf doesn't seem to get updated and a plot from within a function will wipe out a previously generated figure from the main script. Can someone point me to some documentation that will clear this up for me?
Below is a sketch of the kind of thing I am trying to do. When I try passing gcf as an argument I still get inconsistent results.
% main part of script
t=0:100; y=sin(2*pi*t/20); figure(1); plot(t,y); dummy=RoutineThatDoesPlotting(t,y);
….. % end of script
function dummy=RoutineThatDoesPlotting(t,y); figure(gcf+1); plot(t,y); dummy=1; % end of function
Thanks for your help.
Dave

Best Answer

gcf is basically the handle to the last figure window that you actued upon or brought up. It is the "current" one that things will happen in unless you specify otherwise. I don't think figure(gcf+1) is a wise idea though, because gcf won't always be an integer. It may have some weird handle number like 178.372, especially if it was created by running an app built with GUIDE. Just say fh = figure; instead, and that will create a figure and pick a handle number for it automatically rather than you trying to force it to use some particular number.
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