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Switch correctly to the user's default matplotlib backend after inline....
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.

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pylabtools.py
338 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.
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)