We've had users run into the same problem (and have a similar reaction). At least on our end, there was a key assumption that users were making about how a plotting system worked. They expected to be able to do something like this:
... plot stuff here if outputFile: P.savefig( "plot.png" ) else: P.show() The thing they were missing is that they assumed that you don't need to have anything to do w/ the GUI until it pops up on the screen (i.e. until the show call) which just isn't true right now. Depending on the backend, the gui is a required element during the construction of the plot because it's doing the drawing and layout. One item we thought might help (or at least be more obvious) but haven't had time to look at what it would take to implement is to be able to control the backend on a per figure basis - more of an object-oriented control after you create a figure. Something along the lines of: f = Figure(...) if outputFile: f.set_backend( "agg" ) ... Ted ________________________________________ From: Michael Droettboom [md...@stsci.edu] Sent: Thursday, July 08, 2010 8:02 AM To: matplotlib-devel@lists.sourceforge.net Subject: Re: [matplotlib-devel] nasty import behavior It's not that simple. In order to get text metrics and start laying out a plot for some backends (notably Gtk and Wx), the GUI framework needs to be imported. Sure, we could import them on demand once the user actually starts doing stuff, but that would require sprinkling the code with "import gtk" (etc.) in a number of functions, possibly decreasing performance, and it would only delay the kind of exception you point out, not eliminate it. Mike On 07/08/2010 10:16 AM, Neal Becker wrote: > Thanks for the info, but I still think this is rude behavior for a python > module, and believe it would be a good thing to fix it. > > Michael Droettboom wrote: > > >> You need to set your backend to a non-GUI one (such as Agg) if you want >> to run without a display. This FAQ answer may be helpful: >> >> http://matplotlib.sourceforge.net/faq/howto_faq.html#matplotlib-in-a-web- >> > application-server > >> Mike >> >> On 07/08/2010 08:26 AM, Neal Becker wrote: >> >>> A python module of mine could draw a plot, and so imports from >>> matplotlib. Actually, plotting is part of the module test that is in >>> if __name__==__main__ >>> >>> But this kills my job trying to run non-interactively. >>> This is IMO rather nasty behavior. matplotlib should not try to open the >>> display just because you import it. >>> >>> from matplotlib.pyplot import * >>> File "/usr/lib64/python2.6/site-packages/matplotlib/pyplot.py", line >>> 78, >>> in<module> >>> new_figure_manager, draw_if_interactive, show = pylab_setup() >>> File >>> "/usr/lib64/python2.6/site-packages/matplotlib/backends/__init__.py", >>> line 25, in pylab_setup >>> globals(),locals(),[backend_name]) >>> File "/usr/lib64/python2.6/site- >>> packages/matplotlib/backends/backend_gtkagg.py", line 10, in<module> >>> from matplotlib.backends.backend_gtk import gtk, FigureManagerGTK, >>> FigureCanvasGTK,\ >>> File "/usr/lib64/python2.6/site- >>> packages/matplotlib/backends/backend_gtk.py", line 8, in<module> >>> import gtk; gdk = gtk.gdk >>> File "/usr/lib64/python2.6/site-packages/gtk-2.0/gtk/__init__.py", >>> line >>> 64, in<module> >>> _init() >>> File "/usr/lib64/python2.6/site-packages/gtk-2.0/gtk/__init__.py", >>> line >>> 52, in _init >>> _gtk.init_check() >>> RuntimeError: could not open display >>> >>> >>> >>> >>> > ------------------------------------------------------------------------------ > >>> This SF.net email is sponsored by Sprint >>> What will you do first with EVO, the first 4G phone? >>> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first >>> _______________________________________________ >>> Matplotlib-devel mailing list >>> Matplotlib-devel@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/matplotlib-devel >>> >>> >> >> > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Sprint > What will you do first with EVO, the first 4G phone? > Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first > _______________________________________________ > Matplotlib-devel mailing list > Matplotlib-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/matplotlib-devel > -- Michael Droettboom Science Software Branch Space Telescope Science Institute Baltimore, Maryland, USA ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel ------------------------------------------------------------------------------ This SF.net email is sponsored by Sprint What will you do first with EVO, the first 4G phone? Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first _______________________________________________ Matplotlib-devel mailing list Matplotlib-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/matplotlib-devel
