[ChangeSet] print.m: support for figure handles

[Ben Abbott]

On Feb 29, 2008, at 5:24 PM, John W. Eaton wrote:

> On 29-Feb-2008, Ben Abbott wrote:
>
> | On Friday, February 29, 2008, at 10:40AM, "Søren Hauberg" <soren at hauberg.org 
> > wrote:
> | >
> | >fre, 29 02 2008 kl. 07:05 -0800, skrev Ben Abbott:
> | >> I modified print.m to support a figure handle as an input.
> | >>
> | >> It is a trivial change, but permits printing as is often done  
> (by me) in Matlab. For example,
> | >>
> | >>    print (gcf, '-pdf', 'foo.pdf')
> | >>
> | >> Please consider the attached changeset.
> | >I don't know how matlab works, but wouldn't it make sense to do
> | >something like
> | >
> | >if (ishandle (arg))
> | >  old_fig = gcf();
> | >  figure (arg);
> | >endif
> | >
> | >...
> | >
> | >if (ishandle(arg))
> | >  figure(old_fig);
> | >endif
> | >
> | >such that the current figure is still the current figure after  
> the call
> | >to 'print' ?
> | >
> | >Søren
> | >
> |
> | Good point. Matlab respects that behavior as well.
> |
> | I've attached the correct changeset.
>
> When you want to make a temporary change to some global state like the
> current figure, you should use unwind_protect to prevent the change
> from sticking in case an error occurs or an interrupt arrives while
> the setting is in the changed state.  For example
>
>  old_fig = get (0, 'currentfigure');
>  unwind_protect
>    figure (arg);
>    ...
>  unwind_protect_cleanup
>    if (ishandle (old_fig))
>      figure (old_fig)
>    endif
>  end_unwind_protect
>
> jwe

ahhh-ha ... very cool!

I'll make the change!

The indent between unwind_protect and the cleanup will mean nearly all  
lines will be included in the changeset. Is that ok?

Ben