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Merge pull request #4230 from fperez/mpl-backends...
Merge pull request #4230 from fperez/mpl-backends Switch correctly to the user's default matplotlib backend after inline. If '%matplotlib inline' was called first, we'd incorrectly revert to inline when plain '%matplotlib' was called, instead of loading the user's default GUI. If the user called '%matplotlib' first (without 'inline') it worked correctly, but not in the other order. The fix is to read the backend from the original defaults, not from the runtime data structure. Requires matplotlib 1.1

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pylabtools.py
339 lines | 11.4 KiB | text/x-python | PythonLexer
# -*- coding: utf-8 -*-
"""Pylab (matplotlib) support utilities.
Authors
-------
* Fernando Perez.
* Brian Granger
"""
#-----------------------------------------------------------------------------
# Copyright (C) 2009 The IPython Development Team
#
# Distributed under the terms of the BSD License. The full license is in
# the file COPYING, distributed as part of this software.
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
import sys
from io import BytesIO
from IPython.core.display import _pngxy
from IPython.utils.decorators import flag_calls
# If user specifies a GUI, that dictates the backend, otherwise we read the
# user's mpl default from the mpl rc structure
backends = {'tk': 'TkAgg',
'gtk': 'GTKAgg',
'wx': 'WXAgg',
'qt': 'Qt4Agg', # qt3 not supported
'qt4': 'Qt4Agg',
'osx': 'MacOSX',
'inline' : 'module://IPython.kernel.zmq.pylab.backend_inline'}
# We also need a reverse backends2guis mapping that will properly choose which
# GUI support to activate based on the desired matplotlib backend. For the
# most part it's just a reverse of the above dict, but we also need to add a
# few others that map to the same GUI manually:
backend2gui = dict(zip(backends.values(), backends.keys()))
# Our tests expect backend2gui to just return 'qt'
backend2gui['Qt4Agg'] = 'qt'
# In the reverse mapping, there are a few extra valid matplotlib backends that
# map to the same GUI support
backend2gui['GTK'] = backend2gui['GTKCairo'] = 'gtk'
backend2gui['WX'] = 'wx'
backend2gui['CocoaAgg'] = 'osx'
#-----------------------------------------------------------------------------
# Matplotlib utilities
#-----------------------------------------------------------------------------
def getfigs(*fig_nums):
"""Get a list of matplotlib figures by figure numbers.
If no arguments are given, all available figures are returned. If the
argument list contains references to invalid figures, a warning is printed
but the function continues pasting further figures.
Parameters
----------
figs : tuple
A tuple of ints giving the figure numbers of the figures to return.
"""
from matplotlib._pylab_helpers import Gcf
if not fig_nums:
fig_managers = Gcf.get_all_fig_managers()
return [fm.canvas.figure for fm in fig_managers]
else:
figs = []
for num in fig_nums:
f = Gcf.figs.get(num)
if f is None:
print('Warning: figure %s not available.' % num)
else:
figs.append(f.canvas.figure)
return figs
def figsize(sizex, sizey):
"""Set the default figure size to be [sizex, sizey].
This is just an easy to remember, convenience wrapper that sets::
matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
"""
import matplotlib
matplotlib.rcParams['figure.figsize'] = [sizex, sizey]
def print_figure(fig, fmt='png'):
"""Convert a figure to svg or png for inline display."""
from matplotlib import rcParams
# When there's an empty figure, we shouldn't return anything, otherwise we
# get big blank areas in the qt console.
if not fig.axes and not fig.lines:
return
fc = fig.get_facecolor()
ec = fig.get_edgecolor()
bytes_io = BytesIO()
dpi = rcParams['savefig.dpi']
if fmt == 'retina':
dpi = dpi * 2
fmt = 'png'
fig.canvas.print_figure(bytes_io, format=fmt, bbox_inches='tight',
facecolor=fc, edgecolor=ec, dpi=dpi)
data = bytes_io.getvalue()
return data
def retina_figure(fig):
"""format a figure as a pixel-doubled (retina) PNG"""
pngdata = print_figure(fig, fmt='retina')
w, h = _pngxy(pngdata)
metadata = dict(width=w//2, height=h//2)
return pngdata, metadata
# We need a little factory function here to create the closure where
# safe_execfile can live.
def mpl_runner(safe_execfile):
"""Factory to return a matplotlib-enabled runner for %run.
Parameters
----------
safe_execfile : function
This must be a function with the same interface as the
:meth:`safe_execfile` method of IPython.
Returns
-------
A function suitable for use as the ``runner`` argument of the %run magic
function.
"""
def mpl_execfile(fname,*where,**kw):
"""matplotlib-aware wrapper around safe_execfile.
Its interface is identical to that of the :func:`execfile` builtin.
This is ultimately a call to execfile(), but wrapped in safeties to
properly handle interactive rendering."""
import matplotlib
import matplotlib.pylab as pylab
#print '*** Matplotlib runner ***' # dbg
# turn off rendering until end of script
is_interactive = matplotlib.rcParams['interactive']
matplotlib.interactive(False)
safe_execfile(fname,*where,**kw)
matplotlib.interactive(is_interactive)
# make rendering call now, if the user tried to do it
if pylab.draw_if_interactive.called:
pylab.draw()
pylab.draw_if_interactive.called = False
return mpl_execfile
def select_figure_format(shell, fmt):
"""Select figure format for inline backend, can be 'png', 'retina', or 'svg'.
Using this method ensures only one figure format is active at a time.
"""
from matplotlib.figure import Figure
from IPython.kernel.zmq.pylab import backend_inline
svg_formatter = shell.display_formatter.formatters['image/svg+xml']
png_formatter = shell.display_formatter.formatters['image/png']
if fmt == 'png':
svg_formatter.type_printers.pop(Figure, None)
png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png'))
elif fmt in ('png2x', 'retina'):
svg_formatter.type_printers.pop(Figure, None)
png_formatter.for_type(Figure, retina_figure)
elif fmt == 'svg':
png_formatter.type_printers.pop(Figure, None)
svg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'svg'))
else:
raise ValueError("supported formats are: 'png', 'retina', 'svg', not %r" % fmt)
# set the format to be used in the backend()
backend_inline._figure_format = fmt
#-----------------------------------------------------------------------------
# Code for initializing matplotlib and importing pylab
#-----------------------------------------------------------------------------
def find_gui_and_backend(gui=None, gui_select=None):
"""Given a gui string return the gui and mpl backend.
Parameters
----------
gui : str
Can be one of ('tk','gtk','wx','qt','qt4','inline').
gui_select : str
Can be one of ('tk','gtk','wx','qt','qt4','inline').
This is any gui already selected by the shell.
Returns
-------
A tuple of (gui, backend) where backend is one of ('TkAgg','GTKAgg',
'WXAgg','Qt4Agg','module://IPython.kernel.zmq.pylab.backend_inline').
"""
import matplotlib
if gui and gui != 'auto':
# select backend based on requested gui
backend = backends[gui]
else:
# We need to read the backend from the original data structure, *not*
# from mpl.rcParams, since a prior invocation of %matplotlib may have
# overwritten that.
# WARNING: this assumes matplotlib 1.1 or newer!!
backend = matplotlib.rcParamsOrig['backend']
# In this case, we need to find what the appropriate gui selection call
# should be for IPython, so we can activate inputhook accordingly
gui = backend2gui.get(backend, None)
# If we have already had a gui active, we need it and inline are the
# ones allowed.
if gui_select and gui != gui_select:
gui = gui_select
backend = backends[gui]
return gui, backend
def activate_matplotlib(backend):
"""Activate the given backend and set interactive to True."""
import matplotlib
matplotlib.interactive(True)
# Matplotlib had a bug where even switch_backend could not force
# the rcParam to update. This needs to be set *before* the module
# magic of switch_backend().
matplotlib.rcParams['backend'] = backend
import matplotlib.pyplot
matplotlib.pyplot.switch_backend(backend)
# This must be imported last in the matplotlib series, after
# backend/interactivity choices have been made
import matplotlib.pylab as pylab
pylab.show._needmain = False
# We need to detect at runtime whether show() is called by the user.
# For this, we wrap it into a decorator which adds a 'called' flag.
pylab.draw_if_interactive = flag_calls(pylab.draw_if_interactive)
def import_pylab(user_ns, import_all=True):
"""Populate the namespace with pylab-related values.
Imports matplotlib, pylab, numpy, and everything from pylab and numpy.
Also imports a few names from IPython (figsize, display, getfigs)
"""
# Import numpy as np/pyplot as plt are conventions we're trying to
# somewhat standardize on. Making them available to users by default
# will greatly help this.
s = ("import numpy\n"
"import matplotlib\n"
"from matplotlib import pylab, mlab, pyplot\n"
"np = numpy\n"
"plt = pyplot\n"
)
exec s in user_ns
if import_all:
s = ("from matplotlib.pylab import *\n"
"from numpy import *\n")
exec s in user_ns
# IPython symbols to add
user_ns['figsize'] = figsize
from IPython.core.display import display
# Add display and getfigs to the user's namespace
user_ns['display'] = display
user_ns['getfigs'] = getfigs
def configure_inline_support(shell, backend):
"""Configure an IPython shell object for matplotlib use.
Parameters
----------
shell : InteractiveShell instance
backend : matplotlib backend
"""
# If using our svg payload backend, register the post-execution
# function that will pick up the results for display. This can only be
# done with access to the real shell object.
# Note: if we can't load the inline backend, then there's no point
# continuing (such as in terminal-only shells in environments without
# zeromq available).
try:
from IPython.kernel.zmq.pylab.backend_inline import InlineBackend
except ImportError:
return
from matplotlib import pyplot
cfg = InlineBackend.instance(parent=shell)
cfg.shell = shell
if cfg not in shell.configurables:
shell.configurables.append(cfg)
if backend == backends['inline']:
from IPython.kernel.zmq.pylab.backend_inline import flush_figures
shell.register_post_execute(flush_figures)
# Save rcParams that will be overwrittern
shell._saved_rcParams = dict()
for k in cfg.rc:
shell._saved_rcParams[k] = pyplot.rcParams[k]
# load inline_rc
pyplot.rcParams.update(cfg.rc)
else:
from IPython.kernel.zmq.pylab.backend_inline import flush_figures
if flush_figures in shell._post_execute:
shell._post_execute.pop(flush_figures)
if hasattr(shell, '_saved_rcParams'):
pyplot.rcParams.update(shell._saved_rcParams)
del shell._saved_rcParams
# Setup the default figure format
select_figure_format(shell, cfg.figure_format)