the __future__ is now.
the __future__ is now.

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pylabtools.py
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# -*- coding: utf-8 -*-
"""Pylab (matplotlib) support utilities."""
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
from io import BytesIO
from IPython.core.display import _pngxy
from IPython.utils.decorators import flag_calls
from IPython.utils import py3compat
# 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',
'gtk3': 'GTK3Agg',
'wx': 'WXAgg',
'qt': 'Qt4Agg', # qt3 not supported
'qt4': 'Qt4Agg',
'qt5': 'Qt5Agg',
'osx': 'MacOSX',
'nbagg': 'nbAgg',
'notebook': 'nbAgg',
'agg': 'agg',
'inline' : 'module://ipykernel.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['GTK3Cairo'] = 'gtk3'
backend2gui['WX'] = 'wx'
backend2gui['CocoaAgg'] = 'osx'
# And some backends that don't need GUI integration
del backend2gui['nbAgg']
del backend2gui['agg']
del backend2gui['module://ipykernel.pylab.backend_inline']
#-----------------------------------------------------------------------------
# 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', bbox_inches='tight', **kwargs):
"""Print a figure to an image, and return the resulting file data
Returned data will be bytes unless ``fmt='svg'``,
in which case it will be unicode.
Any keyword args are passed to fig.canvas.print_figure,
such as ``quality`` or ``bbox_inches``.
"""
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
dpi = fig.dpi
if fmt == 'retina':
dpi = dpi * 2
fmt = 'png'
# build keyword args
kw = dict(
format=fmt,
facecolor=fig.get_facecolor(),
edgecolor=fig.get_edgecolor(),
dpi=dpi,
bbox_inches=bbox_inches,
)
# **kwargs get higher priority
kw.update(kwargs)
bytes_io = BytesIO()
fig.canvas.print_figure(bytes_io, **kw)
data = bytes_io.getvalue()
if fmt == 'svg':
data = data.decode('utf-8')
return data
def retina_figure(fig, **kwargs):
"""format a figure as a pixel-doubled (retina) PNG"""
pngdata = print_figure(fig, fmt='retina', **kwargs)
# Make sure that retina_figure acts just like print_figure and returns
# None when the figure is empty.
if pngdata is None:
return
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.pyplot as plt
#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 plt.draw_if_interactive.called:
plt.draw()
plt.draw_if_interactive.called = False
# re-draw everything that is stale
try:
da = plt.draw_all
except AttributeError:
pass
else:
da()
return mpl_execfile
def _reshow_nbagg_figure(fig):
"""reshow an nbagg figure"""
try:
reshow = fig.canvas.manager.reshow
except AttributeError:
raise NotImplementedError()
else:
reshow()
def select_figure_formats(shell, formats, **kwargs):
"""Select figure formats for the inline backend.
Parameters
==========
shell : InteractiveShell
The main IPython instance.
formats : str or set
One or a set of figure formats to enable: 'png', 'retina', 'jpeg', 'svg', 'pdf'.
**kwargs : any
Extra keyword arguments to be passed to fig.canvas.print_figure.
"""
import matplotlib
from matplotlib.figure import Figure
svg_formatter = shell.display_formatter.formatters['image/svg+xml']
png_formatter = shell.display_formatter.formatters['image/png']
jpg_formatter = shell.display_formatter.formatters['image/jpeg']
pdf_formatter = shell.display_formatter.formatters['application/pdf']
if isinstance(formats, py3compat.string_types):
formats = {formats}
# cast in case of list / tuple
formats = set(formats)
[ f.pop(Figure, None) for f in shell.display_formatter.formatters.values() ]
if matplotlib.get_backend().lower() == 'nbagg':
formatter = shell.display_formatter.ipython_display_formatter
formatter.for_type(Figure, _reshow_nbagg_figure)
supported = {'png', 'png2x', 'retina', 'jpg', 'jpeg', 'svg', 'pdf'}
bad = formats.difference(supported)
if bad:
bs = "%s" % ','.join([repr(f) for f in bad])
gs = "%s" % ','.join([repr(f) for f in supported])
raise ValueError("supported formats are: %s not %s" % (gs, bs))
if 'png' in formats:
png_formatter.for_type(Figure, lambda fig: print_figure(fig, 'png', **kwargs))
if 'retina' in formats or 'png2x' in formats:
png_formatter.for_type(Figure, lambda fig: retina_figure(fig, **kwargs))
if 'jpg' in formats or 'jpeg' in formats:
jpg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'jpg', **kwargs))
if 'svg' in formats:
svg_formatter.for_type(Figure, lambda fig: print_figure(fig, 'svg', **kwargs))
if 'pdf' in formats:
pdf_formatter.for_type(Figure, lambda fig: print_figure(fig, 'pdf', **kwargs))
#-----------------------------------------------------------------------------
# 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','agg').
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://ipykernel.pylab.backend_inline','agg').
"""
import matplotlib
if gui and gui != 'auto':
# select backend based on requested gui
backend = backends[gui]
if gui == 'agg':
gui = None
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.pyplot as plt
plt.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.
plt.draw_if_interactive = flag_calls(plt.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, user_ns)
if import_all:
s = ("from matplotlib.pylab import *\n"
"from numpy import *\n")
exec(s, 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 ipykernel.pylab.backend_inline import InlineBackend
except ImportError:
return
import matplotlib
cfg = InlineBackend.instance(parent=shell)
cfg.shell = shell
if cfg not in shell.configurables:
shell.configurables.append(cfg)
if backend == backends['inline']:
from ipykernel.pylab.backend_inline import flush_figures
shell.events.register('post_execute', flush_figures)
# Save rcParams that will be overwrittern
shell._saved_rcParams = dict()
for k in cfg.rc:
shell._saved_rcParams[k] = matplotlib.rcParams[k]
# load inline_rc
matplotlib.rcParams.update(cfg.rc)
new_backend_name = "inline"
else:
from ipykernel.pylab.backend_inline import flush_figures
try:
shell.events.unregister('post_execute', flush_figures)
except ValueError:
pass
if hasattr(shell, '_saved_rcParams'):
matplotlib.rcParams.update(shell._saved_rcParams)
del shell._saved_rcParams
new_backend_name = "other"
# only enable the formats once -> don't change the enabled formats (which the user may
# has changed) when getting another "%matplotlib inline" call.
# See https://github.com/ipython/ipykernel/issues/29
cur_backend = getattr(configure_inline_support, "current_backend", "unset")
if new_backend_name != cur_backend:
# Setup the default figure format
select_figure_formats(shell, cfg.figure_formats, **cfg.print_figure_kwargs)
configure_inline_support.current_backend = new_backend_name