Re: [matplotlib-devel] savefig problem in interactive mode

[John H. <jdh...@ac...>]

>>>>> "Fernando" == Fernando Perez <Fer...@co...> writes:

    Fernando> Hi all, I have a question: in interactive (ipython
    Fernando> -pylab) mode, a call to savefig('foo.eps') (either via
    Fernando> %run or straight at the prompt) still pops up a GUI plot
    Fernando> window.  If I run the same script from a system command
    Fernando> line, the eps is made, but no GUI opens (what I consider
    Fernando> the correct behavior).

    Fernando> Is this something that should be fixed in ipython or in
    Fernando> matplotlib?

For the sake of clarity, let's consider the canonical script

    import matplotlib
    matplotlib.use('PS')
    from pylab import *
    plot([1,2,3])
    savefig('test.ps')
    show()

When run from the shell, it does what you want -- makes a PS with no
popup.  It fails in  ipython (pops up a window) because you have
already selected a backend and all pylab commands are directed to that
backend.

How to fix it?

 * ipython invokes an external python process to run each script.  Of
   course you pay a performance hit here, and this would likely change
   the meaning of the way run is meant to work (eg, are local ipython
   shell vars available in a "run" script.

 * provide better support for backend switching in matplotlib.  Eg,
   allowing you at any time to call matplotlib.use.  Currently, this
   only works before the import of pylab.  It may be possible to write
   a pylab.use that simply rebinds the 4 backend functions:
   new_figure_manager, error_msg, draw_if_interactive, show.  At the
   end of a "run", you could simply do a
   matplotlib.pylab.use(defaultBackend) to rebind.  run could be
   enhanced to support backend switching

     run somescript.py -dPS

   much like one can do from the shell.

  You know more about python module reloading than I do.  How does one
  force a module to reload, eg if I wanted to set the rc 'backend'
  param and then do, eg

 
    rcParams['backend'] = 'PS'
    from backends import new_figure_manager, error_msg, draw_if_interactive, show


  to get new symbols?

There may be another way, but those two come to mind.  I'll mull it
over.

    Fernando> ps. Yes, John, I've finally started to use matplotlib
    Fernando> for my own work.  Brace yourself, I'm compiling a pretty
    Fernando> hefty list of things to do.  I hope you don't plan on
    Fernando> sleeping much in the coming months ;)

Well, I knew it was coming....  Stress tests are usually a good
thing.  Plus, I'm sure you can't do anything to interrupt my sleep
that my 3 kids haven't already mastered!

JDH