Sep 18, 2019 · Mar 3, 2019 · Mar 4, 2019 · Mar 4, 2019
diff --git a/lib/matplotlib/_pylab_helpers.py b/lib/matplotlib/_pylab_helpers.py
 """
 Manage figures for pyplot interface.
 Manage figures forthepyplot interface.
 """

 import atexit
 from collections import OrderedDict
 import gc


 class Gcf:
    """
    Singleton to manage a set of integer-numbered figures.
    Singleton to maintain the relation between figures and their managers, and
    keep track of and "active" figure and manager.

    This class is never instantiated; it consists of two class
    attributes (a list and a dictionary), and a set of static
    methods that operate on those attributes, accessing them
    directly as class attributes.
    The canvas of a figure created through pyplot is associated with a figure
    manager, which handles the interaction between the figure and the backend.
    pyplot keeps track of figure managers using an identifier, the "figure
    number" or "manager number" (which can actually be any hashable value);
    this number is available as the :attr:`number` attribute of the manager.

    This class is never instantiated; it consists of an `OrderedDict` mapping
    figure/manager numbers to managers, and a set of class methods that
    manipulate this `OrderedDict`.

    Attributes
    ----------
    figs
          dictionary of the form {*num*: *manager*, ...}
    _activeQue
          list of *managers*, with active one at the end

    figs : OrderedDict
        `OrderedDict` mapping numbers to managers; the active manager is at the
        end.
    """
    _activeQue = []
    figs ={}

    figs =OrderedDict()

    @classmethod
    def get_fig_manager(cls, num):
        """
        Iffiguremanager *num* exists, make it the active
 figure and return the manager;otherwise return *None*.
        If managernumber*num* exists, make it the active one and return it;
        otherwise return *None*.
        """
        manager = cls.figs.get(num, None)
        if manager is not None:
    @classmethod
    def destroy(cls, num):
        """
 Try to remove all traces offigure *num*.
 Destroyfigure number *num*.

        In the interactive backends, this is bound to the
 window "destroy" and"delete" events.
        In the interactive backends, this is bound to the window "destroy" and
        "delete" events.
        """
        if not cls.has_fignum(num):
            return
        manager = cls.figs[num]
        manager = cls.figs.pop(num)
        manager.canvas.mpl_disconnect(manager._cidgcf)
        cls._activeQue.remove(manager)
        del cls.figs[num]
        manager.destroy()
        gc.collect(1)

    @classmethod
    def destroy_fig(cls, fig):
        "*fig* is a Figure instance"
 num =next((manager.num for manager in cls.figs.values()
            ifmanager.canvas.figure == fig), None)
 ifnumis notNone:
 cls.destroy(num)
        """Destroy figure*fig*."""
 canvas =getattr(fig, "canvas", None)
        manager = getattr(canvas, "manager", None)
        num= getattr(manager, "num",None)
        cls.destroy(num)

    @classmethod
    def destroy_all(cls):
        # this is need to ensure that gc is available in corner cases
        # where modules are being torn down after install with easy_install
        import gc  # noqa
        """Destroy all figures."""
        # Reimport gc in case the module globals have already been removed
        # during interpreter shutdown.
        import gc
        for manager in list(cls.figs.values()):
            manager.canvas.mpl_disconnect(manager._cidgcf)
            manager.destroy()

        cls._activeQue = []
        cls.figs.clear()
        gc.collect(1)

    @classmethod
    def has_fignum(cls, num):
        """
        Return *True* if figure *num* exists.
        """
        """Return whether figure number *num* exists."""
        return num in cls.figs

    @classmethod
    def get_all_fig_managers(cls):
        """
        Return a list of figure managers.
        """
        """Return a list of figure managers."""
        return list(cls.figs.values())

    @classmethod
    def get_num_fig_managers(cls):
        """
        Return the number of figures being managed.
        """
        """Return the number of figures being managed."""
        return len(cls.figs)

    @classmethod
    def get_active(cls):
        """
        Return the manager of the active figure, or *None*.
        """
        if len(cls._activeQue) == 0:
            return None
        else:
            return cls._activeQue[-1]
        """Return the active manager, or *None* if there is no manager."""
        return next(reversed(cls.figs.values())) if cls.figs else None

    @classmethod
    def set_active(cls, manager):
        """
        Make the figure corresponding to *manager* the active one.
        """
        oldQue = cls._activeQue[:]
        cls._activeQue = [m for m in oldQue if m != manager]
        cls._activeQue.append(manager)
        """Make *manager* the active manager."""
        cls.figs[manager.num] = manager
        cls.figs.move_to_end(manager.num)

    @classmethod
    def draw_all(cls, force=False):
        """
        Redraw all figures registered with the pyplot
 state machine.
        Redraw allstale managedfigures, or, if *force* is True, all managed
 figures.
        """
        for f_mgr in cls.get_all_fig_managers():
            if force or f_mgr.canvas.figure.stale:
                f_mgr.canvas.draw_idle()
        for manager in cls.get_all_fig_managers():
            if force or manager.canvas.figure.stale:
                manager.canvas.draw_idle()


 atexit.register(Gcf.destroy_all)
Original file line number	Diff line number	Diff line change
		@@ -1,36 +1,41 @@
		"""
		Manage figures for pyplot interface.
		Manage figures forthepyplot interface.
		"""

		import atexit
		from collections import OrderedDict
		import gc


		class Gcf:
		"""
		Singleton to manage a set of integer-numbered figures.
		Singleton to maintain the relation between figures and their managers, and
		keep track of and "active" figure and manager.

		This class is never instantiated; it consists of two class
		attributes (a list and a dictionary), and a set of static
		methods that operate on those attributes, accessing them
		directly as class attributes.
		The canvas of a figure created through pyplot is associated with a figure
		manager, which handles the interaction between the figure and the backend.
		pyplot keeps track of figure managers using an identifier, the "figure
		number" or "manager number" (which can actually be any hashable value);
		this number is available as the :attr:`number` attribute of the manager.

		This class is never instantiated; it consists of an `OrderedDict` mapping
		figure/manager numbers to managers, and a set of class methods that
		manipulate this `OrderedDict`.

		Attributes
		----------
		figs
		dictionary of the form {num: manager, ...}
		_activeQue
		list of managers, with active one at the end

		figs : OrderedDict
		`OrderedDict` mapping numbers to managers; the active manager is at the
		end.
		"""
		_activeQue = []
		figs ={}

		figs =OrderedDict()

		@classmethod
		def get_fig_manager(cls, num):
		"""
		Iffiguremanager num exists, make it the active
		figure and return the manager;otherwise return None.
		If managernumbernum exists, make it the active one and return it;
		otherwise return None.
		"""
		manager = cls.figs.get(num, None)
		if manager is not None:
Expand All		@@ -40,90 +45,73 @@ def get_fig_manager(cls, num):
		@classmethod
		def destroy(cls, num):
		"""
		Try to remove all traces offigure num.
		Destroyfigure number num.

		In the interactive backends, this is bound to the
		window "destroy" and"delete" events.
		In the interactive backends, this is bound to the window "destroy" and
		"delete" events.
		"""
		if not cls.has_fignum(num):
		return
		manager = cls.figs[num]
		manager = cls.figs.pop(num)
		manager.canvas.mpl_disconnect(manager._cidgcf)
		cls._activeQue.remove(manager)
		del cls.figs[num]
		manager.destroy()
		gc.collect(1)

		@classmethod
		def destroy_fig(cls, fig):
		"fig is a Figure instance"
		num =next((manager.num for manager in cls.figs.values()
		ifmanager.canvas.figure == fig), None)
		ifnumis notNone:
		cls.destroy(num)
		"""Destroy figurefig."""
		canvas =getattr(fig, "canvas", None)
		manager = getattr(canvas, "manager", None)
		num= getattr(manager, "num",None)
Copy link Member QuLogicMar 4, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Is this always equivalent, since it seems to be working in reverse? Copy link ContributorAuthor anntzerMar 4, 2019 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. This basically gets`fig.canvas.manager.num` with the provision that each of these can be None. If this num is not registered in the`figs` dict,`destroy` will catch that as it first checks`cls.has_fignum(num)`. It's true that this may cause problems if two managers share the same num, but then the num->manager mapping is already invalid (`set_active` will already have overwritten the entry in the dict) so I'm not too worried about that.
		cls.destroy(num)

		@classmethod
		def destroy_all(cls):
		# this is need to ensure that gc is available in corner cases
		# where modules are being torn down after install with easy_install
		import gc # noqa
		"""Destroy all figures."""
		# Reimport gc in case the module globals have already been removed
		# during interpreter shutdown.
		import gc
		for manager in list(cls.figs.values()):
		manager.canvas.mpl_disconnect(manager._cidgcf)
		manager.destroy()

		cls._activeQue = []
		cls.figs.clear()
		gc.collect(1)

		@classmethod
		def has_fignum(cls, num):
		"""
		Return True if figure num exists.
		"""
		"""Return whether figure number num exists."""
		return num in cls.figs

		@classmethod
		def get_all_fig_managers(cls):
		"""
		Return a list of figure managers.
		"""
		"""Return a list of figure managers."""
		return list(cls.figs.values())

		@classmethod
		def get_num_fig_managers(cls):
		"""
		Return the number of figures being managed.
		"""
		"""Return the number of figures being managed."""
		return len(cls.figs)

		@classmethod
		def get_active(cls):
		"""
		Return the manager of the active figure, or None.
		"""
		if len(cls._activeQue) == 0:
		return None
		else:
		return cls._activeQue[-1]
		"""Return the active manager, or None if there is no manager."""
		return next(reversed(cls.figs.values())) if cls.figs else None

		@classmethod
		def set_active(cls, manager):
		"""
		Make the figure corresponding to manager the active one.
		"""
		oldQue = cls._activeQue[:]
		cls._activeQue = [m for m in oldQue if m != manager]
		cls._activeQue.append(manager)
		"""Make manager the active manager."""
		cls.figs[manager.num] = manager
		cls.figs.move_to_end(manager.num)

		@classmethod
		def draw_all(cls, force=False):
		"""
		Redraw all figures registered with the pyplot
		state machine.
		Redraw allstale managedfigures, or, if force is True, all managed
		figures.
		"""
		for f_mgr in cls.get_all_fig_managers():
		if force or f_mgr.canvas.figure.stale:
		f_mgr.canvas.draw_idle()
		for manager in cls.get_all_fig_managers():
		if force or manager.canvas.figure.stale:
		manager.canvas.draw_idle()


		atexit.register(Gcf.destroy_all)