Jan 12, 2023 · Jan 12, 2023
diff --git a/lib/matplotlib/quiver.py b/lib/matplotlib/quiver.py

 class Quiver(mcollections.PolyCollection):
    """
    Specialized PolyCollection for arrows.

    The only API method is set_UVC(), which can be used
    to change the size, orientation, and color of the
    arrows; their locations are fixed when the class is
    instantiated.  Possibly this method will be useful
    in animations.

    Much of the work in this class is done in the draw()
    method so that as much information as possible is available
    about the plot.  In subsequent draw() calls, recalculation
    is limited to things that might have changed, so there
    should be no performance penalty from putting the calculations
    in the draw() method.
    Specialized `.PolyCollection` for arrows.

    The only API method is `set_UVC`, which can be used to change the size,
    orientation, and color of the arrows.  Locations are changed using the
    (inherited) `.PolyCollection.set_offsets` method.  This method may be
    useful in animations.
    """

    # Much of the work in this class is done in the draw() method so that as
    # much information as possible is available about the plot.  In subsequent
    # draw() calls, recalculation is limited to things that might have changed,
    # so there should be no performance penalty from putting the calculations
    # in the draw() method.

    _PIVOT_VALS = ('tail', 'middle', 'tip')

    @_docstring.Substitution(_quiver_doc)
        """
        self._axes = ax  # The attr actually set by the Artist.axes property.
        X, Y, U, V, C = _parse_args(*args, caller_name='quiver')
        self.X = X
        self.Y = Y
        self.XY = np.column_stack((X, Y))
        self.N = len(X)
        self.scale = scale
        self.headwidth = headwidth
        self.headlength = float(headlength)
        self.transform = kwargs.pop('transform', ax.transData)
        kwargs.setdefault('facecolors', color)
        kwargs.setdefault('linewidths', (0,))
        super().__init__([], offsets=self.XY, offset_transform=self.transform,
        super().__init__([], offsets=np.column_stack([X, Y]),
                         offset_transform=self.transform,
                         closed=False, **kwargs)
        self.polykw = kwargs
        self.set_UVC(U, V, C)
        self._dpi_at_last_init = None

    XY = property(lambda self: self.get_offsets())
    X = property(lambda self: self.get_offsets()[:, 0])
    Y = property(lambda self: self.get_offsets()[:, 1])
    N = property(lambda self: len(self.get_offsets()))

    def _init(self):
        """
        Initialization delayed until first draw;
        # length = np.minimum(length, 2 ** 16)
        np.clip(length, 0, 2 ** 16, out=length)
        # x, y: normal horizontal arrow
        x = np.array([0, -self.headaxislength,
                      -self.headlength, 0],
                     np.float64)
        x = np.array([0, -self.headaxislength, -self.headlength, 0], float)
        x = x + np.array([0, 1, 1, 1]) * length
        y = 0.5 * np.array([1, 1, self.headwidth, 0],np.float64)
        y = 0.5 * np.array([1, 1, self.headwidth, 0],float)
        y = np.repeat(y[np.newaxis, :], N, axis=0)
        # x0, y0: arrow without shaft, for short vectors
        x0 = np.array([0, minsh - self.headaxislength,
                       minsh - self.headlength, minsh],np.float64)
        y0 = 0.5 * np.array([1, 1, self.headwidth, 0],np.float64)
                       minsh - self.headlength, minsh],float)
        y0 = 0.5 * np.array([1, 1, self.headwidth, 0],float)
        ii = [0, 1, 2, 3, 2, 1, 0, 0]
        X = x[:, ii]
        Y = y[:, ii]

 class Barbs(mcollections.PolyCollection):
    """
    Specialized PolyCollection for barbs.

    The only API method is :meth:`set_UVC`, which can be used to
    change the size, orientation, and color of the arrows.  Locations
    are changed using the :meth:`set_offsets` collection method.
    Possibly this method will be useful in animations.
    Specialized `.PolyCollection` for barbs.

 There is one internal function :meth:`_find_tails` whichfinds
 exactly what should be put on the barb given the vector magnitude.
 From there :meth:`_make_barbs` is used to find the vertices of the
 polygon to represent the barb based on this information.
 The only API method is `set_UVC`, whichcan be used to change the size,
 orientation, and color of the arrows.  Locations are changed using the
 (inherited) `.PolyCollection.set_offsets` method.  This method may be
 useful in animations.
    """

    # This may be an abuse of polygons here to render what is essentially maybe
    # 1 triangle and a series of lines.  It works fine as far as I can tell
    # however.
    # There is one internal function :meth:`_find_tails` which finds
    # exactly what should be put on the barb given the vector magnitude.
    # From there :meth:`_make_barbs` is used to find the vertices of the
    # polygon to represent the barb based on this information.

    @_docstring.interpd
    def __init__(self, ax, *args,
        self._pivot = pivot
        self._length = length

        #Flagcolor and barbcolor provide convenience parameters for
        #flagcolor and barbcolor provide convenience parameters for
        # setting the facecolor and edgecolor, respectively, of the barb
        # polygon.  We also work here to make the flag the same color as the
        # rest of the barb by default

        # Parse out the data arrays from the various configurations supported
        x, y, u, v, c = _parse_args(*args, caller_name='barbs')
        self.x = x
        self.y = y
        xy = np.column_stack((x, y))

        # Make a collection

        self.set_UVC(u, v, c)

    x = property(lambda self: self.get_offsets()[:, 0])
    y = property(lambda self: self.get_offsets()[:, 1])

    def _find_tails(self, mag, rounding=True, half=5, full=10, flag=50):
        """
        Find how many of each of the tail pieces is necessary.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -445,22 +445,20 @@ def _check_consistent_shapes(*arrays):

		class Quiver(mcollections.PolyCollection):
		"""
		Specialized PolyCollection for arrows.

		The only API method is set_UVC(), which can be used
		to change the size, orientation, and color of the
		arrows; their locations are fixed when the class is
		instantiated. Possibly this method will be useful
		in animations.

		Much of the work in this class is done in the draw()
		method so that as much information as possible is available
		about the plot. In subsequent draw() calls, recalculation
		is limited to things that might have changed, so there
		should be no performance penalty from putting the calculations
		in the draw() method.
		Specialized `.PolyCollection` for arrows.

		The only API method is `set_UVC`, which can be used to change the size,
		orientation, and color of the arrows. Locations are changed using the
		(inherited) `.PolyCollection.set_offsets` method. This method may be
		useful in animations.
Comment on lines +451 to +453 Copy link Contributor ianhiJan 12, 2023 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Unfortunately I think the behavior is a little bit more complicated than than just using`set_offsets` due to the interactions of UVC and XY which may be difficult for users to discover. See#22407
		"""

		# Much of the work in this class is done in the draw() method so that as
		# much information as possible is available about the plot. In subsequent
		# draw() calls, recalculation is limited to things that might have changed,
		# so there should be no performance penalty from putting the calculations
		# in the draw() method.

		_PIVOT_VALS = ('tail', 'middle', 'tip')

		@_docstring.Substitution(_quiver_doc)
Expand All		@@ -476,10 +474,6 @@ def __init__(self, ax, *args,
		"""
		self._axes = ax # The attr actually set by the Artist.axes property.
		X, Y, U, V, C = _parse_args(*args, caller_name='quiver')
		self.X = X
		self.Y = Y
		self.XY = np.column_stack((X, Y))
		self.N = len(X)
		self.scale = scale
		self.headwidth = headwidth
		self.headlength = float(headlength)
Expand All		@@ -499,12 +493,18 @@ def __init__(self, ax, *args,
		self.transform = kwargs.pop('transform', ax.transData)
		kwargs.setdefault('facecolors', color)
		kwargs.setdefault('linewidths', (0,))
		super().__init__([], offsets=self.XY, offset_transform=self.transform,
		super().__init__([], offsets=np.column_stack([X, Y]),
		offset_transform=self.transform,
		closed=False, **kwargs)
		self.polykw = kwargs
		self.set_UVC(U, V, C)
		self._dpi_at_last_init = None

		XY = property(lambda self: self.get_offsets())
		X = property(lambda self: self.get_offsets()[:, 0])
		Y = property(lambda self: self.get_offsets()[:, 1])
		N = property(lambda self: len(self.get_offsets()))

		def _init(self):
		"""
		Initialization delayed until first draw;
Expand DownExpand Up		@@ -675,16 +675,14 @@ def _h_arrows(self, length):
		# length = np.minimum(length, 2 ** 16)
		np.clip(length, 0, 2 ** 16, out=length)
		# x, y: normal horizontal arrow
		x = np.array([0, -self.headaxislength,
		-self.headlength, 0],
		np.float64)
		x = np.array([0, -self.headaxislength, -self.headlength, 0], float)
		x = x + np.array([0, 1, 1, 1]) * length
		y = 0.5 * np.array([1, 1, self.headwidth, 0],np.float64)
		y = 0.5 * np.array([1, 1, self.headwidth, 0],float)
		y = np.repeat(y[np.newaxis, :], N, axis=0)
		# x0, y0: arrow without shaft, for short vectors
		x0 = np.array([0, minsh - self.headaxislength,
		minsh - self.headlength, minsh],np.float64)
		y0 = 0.5 * np.array([1, 1, self.headwidth, 0],np.float64)
		minsh - self.headlength, minsh],float)
		y0 = 0.5 * np.array([1, 1, self.headwidth, 0],float)
		ii = [0, 1, 2, 3, 2, 1, 0, 0]
		X = x[:, ii]
		Y = y[:, ii]
Expand DownExpand Up		@@ -866,22 +864,18 @@ def _h_arrows(self, length):

		class Barbs(mcollections.PolyCollection):
		"""
		Specialized PolyCollection for barbs.

		The only API method is :meth:`set_UVC`, which can be used to
		change the size, orientation, and color of the arrows. Locations
		are changed using the :meth:`set_offsets` collection method.
		Possibly this method will be useful in animations.
		Specialized `.PolyCollection` for barbs.

		There is one internal function :meth:`_find_tails` whichfinds
		exactly what should be put on the barb given the vector magnitude.
		From there :meth:`_make_barbs` is used to find the vertices of the
		polygon to represent the barb based on this information.
		The only API method is `set_UVC`, whichcan be used to change the size,
		orientation, and color of the arrows. Locations are changed using the
		(inherited) `.PolyCollection.set_offsets` method. This method may be
		useful in animations.
		"""

		# This may be an abuse of polygons here to render what is essentially maybe
		# 1 triangle and a series of lines. It works fine as far as I can tell
		# however.
		# There is one internal function :meth:`_find_tails` which finds
		# exactly what should be put on the barb given the vector magnitude.
		# From there :meth:`_make_barbs` is used to find the vertices of the
		# polygon to represent the barb based on this information.

		@_docstring.interpd
		def __init__(self, ax, *args,
Expand All		@@ -903,7 +897,7 @@ def __init__(self, ax, *args,
		self._pivot = pivot
		self._length = length

		#Flagcolor and barbcolor provide convenience parameters for
		#flagcolor and barbcolor provide convenience parameters for
		# setting the facecolor and edgecolor, respectively, of the barb
		# polygon. We also work here to make the flag the same color as the
		# rest of the barb by default
Expand All		@@ -928,8 +922,6 @@ def __init__(self, ax, *args,

		# Parse out the data arrays from the various configurations supported
		x, y, u, v, c = _parse_args(*args, caller_name='barbs')
		self.x = x
		self.y = y
		xy = np.column_stack((x, y))

		# Make a collection
Expand All		@@ -940,6 +932,9 @@ def __init__(self, ax, *args,

		self.set_UVC(u, v, c)

		x = property(lambda self: self.get_offsets()[:, 0])
		y = property(lambda self: self.get_offsets()[:, 1])

		def _find_tails(self, mag, rounding=True, half=5, full=10, flag=50):
		"""
		Find how many of each of the tail pieces is necessary.
Expand Down