I’m assuming, you are referring to the
export_fig toolbox by altmany:
altmany/export_fig: A MATLAB toolbox for exporting publication quality figures (github.com)
I couldn’t find documentation for Matlab’s
handle function. But looking at how it is used in
export_fig it probably returns a graphics handle object corresponding to a double class input:
export_fig/export_fig.m at master · altmany/export_fig (github.com)
Octave hasn’t implemented a graphics handle class yet. So that function isn’t available.
Reading a little further from that line, it looks like that part of the code is about handling
uifigure objects (which Octave doesn’t have). So it might be possible to skip that entire section on Octave.
But it also looks like the function relies on Matlab’s undocumented
'JavaFrame' property (at least in that part of the file). There are no plans to supporting that property in Octave. In fact, Octave’s graphics don’t use Java at all. So it is very unlikely it will ever implement that undocumented property.
In the light of that, it might require more changes for that function to support Octave.
You could either try that yourself (given that
export_fig is distributed with BSD 3-clause license). Or try to reach out to the author of
export_fig and ask whether he might be interested in supporting Octave for his toolbox.