Oct 23, 2017 · Oct 24, 2017 · Oct 25, 2017 · Oct 25, 2017 · Nov 17, 2017 · Nov 17, 2017
diff --git a/.gitignore b/.gitignore
 Icon?
 Thumbs.db

 # Things specific to this project #
 ###################################
 lib/matplotlib/mpl-data/matplotlib.conf
 lib/matplotlib/mpl-data/matplotlibrc

 # Documentation generated files #
 #################################
 # sphinx build directory
diff --git a/doc/api/api_changes/20171025-AL-rcParams-backend.rst b/doc/api/api_changes/20171025-AL-rcParams-backend.rst
 Testing multiple candidate backends in rcParams
 ```````````````````````````````````````````````

 It is now possible to set ``rcParams["backend"]`` to a *list* of candidate
 backends.

 If `.pyplot` has already been imported, Matplotlib will try to load each
 candidate backend in the given order until one of them can be loaded
 successfully. ``rcParams["backend"]`` will then be set to the value of the
 successfully loaded backend.  (If `.pyplot` has already been imported and
 ``rcParams["backend"]`` is set to a single value, then the backend will
 likewise be updated.)

 If `.pyplot` has not been imported yet, then ``rcParams["backend"]`` will
 maintain the value as a list, and the loading attempt will occur when `.pyplot`
 is imported.  If you rely on ``rcParams["backend"]`` (or its synonym,
 ``matplotlib.get_backend()`` always being a string, import `.pyplot` to trigger
 backend resolution.

 `matplotlib.use`, `pyplot.switch_backends`, and
 `matplotlib.backends.pylab_setup` have likewise gained the ability to accept a
 list of candidate backends.  Note, however, that the first two functions have
 become redundant with directly setting ``rcParams["backend"]``.
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py

 import numpy
 from six.moves.urllib.request import urlopen
 from six.moves import reload_module as reload

 # Get the version from the _version.py versioneer file. For a git checkout,
 # this is computed based on the number of commits since the last tag.

 # this is the instance used by the matplotlib classes
 rcParams = rc_params()
 if "MPLBACKEND" in os.environ:
    rcParams["backend"] = os.environ["MPLBACKEND"]

 if rcParams['examples.directory']:
    # paths that are intended to be relative to matplotlib_fname()
        dict.update(rcParams, orig)


 _use_error_msg = """
 This call to matplotlib.use() has no effect because the backend has already
 been chosen; matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
 or matplotlib.backends is imported for the first time.

 The backend was *originally* set to {backend!r} by the following code:
 {tb}
 """


 def use(arg, warn=True, force=False):
    """
    Set thematplotlib backend to one of the known backends.
    Set theMatplotlib backend.

    The argument is case-insensitive. *warn* specifies whether a
    warning should be issued if a backend has already been set up.
    *force* is an **experimental** flag that tells matplotlib to
    attempt to initialize a new backend by reloading the backend
    module.
    The argument is case-insensitive.  Switching to an interactive backend is
    only safe if no event loop for another interactive backend has started.
    Switching to and from non-interactive backends is safe.

    .. note::

        This function must be called *before* importing pyplot for
        the first time; or, if you are not using pyplot, it must be called
        before importing matplotlib.backends.  If warn is True, a warning
        is issued if you try and call this after pylab or pyplot have been
        loaded.  In certain black magic use cases, e.g.
        :func:`pyplot.switch_backend`, we are doing the reloading necessary to
        make the backend switch work (in some cases, e.g., pure image
        backends) so one can set warn=False to suppress the warnings.

    To find out which backend is currently set, see
    :func:`matplotlib.get_backend`.
    To find out which backend is currently set, see `matplotlib.get_backend`.

    Parameters
    ----------
    arg : str
        The name of the backend to use.
    """
    # Lets determine the proper backend name first
    if arg.startswith('module://'):
        name = arg
    else:
        # Lowercase only non-module backend names (modules are case-sensitive)
        arg = arg.lower()
        name = validate_backend(arg)

    # Check if we've already set up a backend
    if 'matplotlib.backends' in sys.modules:
        # Warn only if called with a different name
        if (rcParams['backend'] != name) and warn:
            import matplotlib.backends
            warnings.warn(
                _use_error_msg.format(
                    backend=rcParams['backend'],
                    tb=matplotlib.backends._backend_loading_tb),
                stacklevel=2)

        # Unless we've been told to force it, just return
        if not force:
            return
        need_reload = True
    else:
        need_reload = False

    # Store the backend name
    rcParams['backend'] = name

    # If needed we reload here because a lot of setup code is triggered on
    # module import. See backends/__init__.py for more detail.
    if need_reload:
        reload(sys.modules['matplotlib.backends'])


 try:
    use(os.environ['MPLBACKEND'])
 except KeyError:
    pass
    if not isinstance(arg, six.string_types):
        # We want to keep 'use(...); rcdefaults()' working, which means that
        # use(...) needs to force the default backend, and thus be a single
        # string.
        raise TypeError("matplotlib.use takes a single string as argument")
    rcParams["backend"] = \
        rcParamsDefault["backend"] = rcParamsOrig["backend"] = arg


 def get_backend():

        retcode = pytest.main(args, **kwargs)
    finally:
        if old_backend.lower() != 'agg':
            use(old_backend, warn=switch_backend_warn)
        rcParams['backend'] = old_backend
        if recursionlimit:
            sys.setrecursionlimit(old_recursionlimit)
Original file line number	Diff line number	Diff line change
Expand Up		@@ -50,11 +50,6 @@ ehthumbs.db
		Icon?
		Thumbs.db

		# Things specific to this project #
		###################################
		lib/matplotlib/mpl-data/matplotlib.conf
		lib/matplotlib/mpl-data/matplotlibrc

		# Documentation generated files #
		#################################
		# sphinx build directory
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,23 @@
		Testing multiple candidate backends in rcParams
		```````````````````````````````````````````````

		It is now possible to set ``rcParams["backend"]`` to a list of candidate
		backends.

		If `.pyplot` has already been imported, Matplotlib will try to load each
		candidate backend in the given order until one of them can be loaded
		successfully. ``rcParams["backend"]`` will then be set to the value of the
		successfully loaded backend. (If `.pyplot` has already been imported and
		``rcParams["backend"]`` is set to a single value, then the backend will
		likewise be updated.)

		If `.pyplot` has not been imported yet, then ``rcParams["backend"]`` will
		maintain the value as a list, and the loading attempt will occur when `.pyplot`
		is imported. If you rely on ``rcParams["backend"]`` (or its synonym,
		``matplotlib.get_backend()`` always being a string, import `.pyplot` to trigger
		backend resolution.

		`matplotlib.use`, `pyplot.switch_backends`, and
		`matplotlib.backends.pylab_setup` have likewise gained the ability to accept a
		list of candidate backends. Note, however, that the first two functions have
		become redundant with directly setting ``rcParams["backend"]``.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -131,7 +131,6 @@

		import numpy
		from six.moves.urllib.request import urlopen
		from six.moves import reload_module as reload

		# Get the version from the _version.py versioneer file. For a git checkout,
		# this is computed based on the number of commits since the last tag.
Expand DownExpand Up		@@ -1134,6 +1133,8 @@ def rc_params_from_file(fname, fail_on_error=False, use_default_template=True):

		# this is the instance used by the matplotlib classes
		rcParams = rc_params()
		if "MPLBACKEND" in os.environ:
		rcParams["backend"] = os.environ["MPLBACKEND"]

		if rcParams['examples.directory']:
		# paths that are intended to be relative to matplotlib_fname()
Expand DownExpand Up		@@ -1311,80 +1312,28 @@ def rc_context(rc=None, fname=None):
		dict.update(rcParams, orig)


		_use_error_msg = """
		This call to matplotlib.use() has no effect because the backend has already
		been chosen; matplotlib.use() must be called before pylab, matplotlib.pyplot,
		or matplotlib.backends is imported for the first time.

		The backend was originally set to {backend!r} by the following code:
		{tb}
		"""


		def use(arg, warn=True, force=False):
		"""
		Set thematplotlib backend to one of the known backends.
		Set theMatplotlib backend.

		The argument is case-insensitive. warn specifies whether a
		warning should be issued if a backend has already been set up.
		force is an experimental flag that tells matplotlib to
		attempt to initialize a new backend by reloading the backend
		module.
		The argument is case-insensitive. Switching to an interactive backend is
		only safe if no event loop for another interactive backend has started.
		Switching to and from non-interactive backends is safe.

		.. note::

		This function must be called before importing pyplot for
		the first time; or, if you are not using pyplot, it must be called
		before importing matplotlib.backends. If warn is True, a warning
		is issued if you try and call this after pylab or pyplot have been
		loaded. In certain black magic use cases, e.g.
		:func:`pyplot.switch_backend`, we are doing the reloading necessary to
		make the backend switch work (in some cases, e.g., pure image
		backends) so one can set warn=False to suppress the warnings.

		To find out which backend is currently set, see
		:func:`matplotlib.get_backend`.
		To find out which backend is currently set, see `matplotlib.get_backend`.

		Parameters
		----------
		arg : str
		The name of the backend to use.
		"""
		# Lets determine the proper backend name first
		if arg.startswith('module://'):
		name = arg
		else:
		# Lowercase only non-module backend names (modules are case-sensitive)
		arg = arg.lower()
		name = validate_backend(arg)

		# Check if we've already set up a backend
		if 'matplotlib.backends' in sys.modules:
		# Warn only if called with a different name
		if (rcParams['backend'] != name) and warn:
		import matplotlib.backends
		warnings.warn(
		_use_error_msg.format(
		backend=rcParams['backend'],
		tb=matplotlib.backends._backend_loading_tb),
		stacklevel=2)

		# Unless we've been told to force it, just return
		if not force:
		return
		need_reload = True
		else:
		need_reload = False

		# Store the backend name
		rcParams['backend'] = name

		# If needed we reload here because a lot of setup code is triggered on
		# module import. See backends/__init__.py for more detail.
		if need_reload:
		reload(sys.modules['matplotlib.backends'])


		try:
		use(os.environ['MPLBACKEND'])
		except KeyError:
		pass
		if not isinstance(arg, six.string_types):
		# We want to keep 'use(...); rcdefaults()' working, which means that
		# use(...) needs to force the default backend, and thus be a single
		# string.
		raise TypeError("matplotlib.use takes a single string as argument")
		rcParams["backend"] = \
		rcParamsDefault["backend"] = rcParamsOrig["backend"] = arg


		def get_backend():
Expand DownExpand Up		@@ -1508,8 +1457,7 @@ def test(verbosity=None, coverage=False, switch_backend_warn=True,

		retcode = pytest.main(args, **kwargs)
		finally:
		if old_backend.lower() != 'agg':
		use(old_backend, warn=switch_backend_warn)
		rcParams['backend'] = old_backend
		if recursionlimit:
		sys.setrecursionlimit(old_recursionlimit)

Expand Down