Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/mpl_toolkits/axisartist/__init__.py

@@ -0,0 +1,15 @@
+from .axislines import (
+    Axes, AxesZero, AxisArtistHelper, AxisArtistHelperRectlinear,
+    GridHelperBase, GridHelperRectlinear, Subplot, SubplotZero)
+from .axis_artist import AxisArtist, GridlinesCollection
+from .grid_helper_curvelinear import GridHelperCurveLinear
+from .floating_axes import FloatingAxes, FloatingSubplot
+from mpl_toolkits.axes_grid1.parasite_axes import (
+    host_axes_class_factory, parasite_axes_class_factory,
+    parasite_axes_auxtrans_class_factory, subplot_class_factory)
+
+
+ParasiteAxes = parasite_axes_class_factory(Axes)
+ParasiteAxesAuxTrans = parasite_axes_auxtrans_class_factory(ParasiteAxes)
+HostAxes = host_axes_class_factory(Axes)
+SubplotHost = subplot_class_factory(HostAxes)

venv/Lib/site-packages/mpl_toolkits/axisartist/angle_helper.py

@@ -0,0 +1,405 @@
+import numpy as np
+import math
+
+from matplotlib import cbook
+from mpl_toolkits.axisartist.grid_finder import ExtremeFinderSimple
+
+
+def select_step_degree(dv):
+
+    degree_limits_ = [1.5, 3, 7, 13, 20, 40, 70, 120, 270, 520]
+    degree_steps_  = [1,   2, 5, 10, 15, 30, 45,  90, 180, 360]
+    degree_factors = [1.] * len(degree_steps_)
+
+    minsec_limits_ = [1.5, 2.5, 3.5, 8, 11, 18, 25, 45]
+    minsec_steps_  = [1,   2,   3,   5, 10, 15, 20, 30]
+
+    minute_limits_ = np.array(minsec_limits_) / 60
+    minute_factors = [60.] * len(minute_limits_)
+
+    second_limits_ = np.array(minsec_limits_) / 3600
+    second_factors = [3600.] * len(second_limits_)
+
+    degree_limits = [*second_limits_, *minute_limits_, *degree_limits_]
+    degree_steps = [*minsec_steps_, *minsec_steps_, *degree_steps_]
+    degree_factors = [*second_factors, *minute_factors, *degree_factors]
+
+    n = np.searchsorted(degree_limits, dv)
+    step = degree_steps[n]
+    factor = degree_factors[n]
+
+    return step, factor
+
+
+def select_step_hour(dv):
+
+    hour_limits_ = [1.5, 2.5, 3.5, 5, 7, 10, 15, 21, 36]
+    hour_steps_  = [1,   2,   3,   4, 6,  8, 12, 18, 24]
+    hour_factors = [1.] * len(hour_steps_)
+
+    minsec_limits_ = [1.5, 2.5, 3.5, 4.5, 5.5, 8, 11, 14, 18, 25, 45]
+    minsec_steps_  = [1,   2,   3,   4,   5,   6, 10, 12, 15, 20, 30]
+
+    minute_limits_ = np.array(minsec_limits_) / 60
+    minute_factors = [60.] * len(minute_limits_)
+
+    second_limits_ = np.array(minsec_limits_) / 3600
+    second_factors = [3600.] * len(second_limits_)
+
+    hour_limits = [*second_limits_, *minute_limits_, *hour_limits_]
+    hour_steps = [*minsec_steps_, *minsec_steps_, *hour_steps_]
+    hour_factors = [*second_factors, *minute_factors, *hour_factors]
+
+    n = np.searchsorted(hour_limits, dv)
+    step = hour_steps[n]
+    factor = hour_factors[n]
+
+    return step, factor
+
+
+def select_step_sub(dv):
+
+    # subarcsec or degree
+    tmp = 10.**(int(math.log10(dv))-1.)
+
+    factor = 1./tmp
+
+    if 1.5*tmp >= dv:
+        step = 1
+    elif 3.*tmp >= dv:
+        step = 2
+    elif 7.*tmp >= dv:
+        step = 5
+    else:
+        step = 1
+        factor = 0.1*factor
+
+    return step, factor
+
+
+def select_step(v1, v2, nv, hour=False, include_last=True,
+                threshold_factor=3600.):
+
+    if v1 > v2:
+        v1, v2 = v2, v1
+
+    dv = (v2 - v1) / nv
+
+    if hour:
+        _select_step = select_step_hour
+        cycle = 24.
+    else:
+        _select_step = select_step_degree
+        cycle = 360.
+
+    # for degree
+    if dv > 1 / threshold_factor:
+        step, factor = _select_step(dv)
+    else:
+        step, factor = select_step_sub(dv*threshold_factor)
+
+        factor = factor * threshold_factor
+
+    levs = np.arange(np.floor(v1 * factor / step),
+                     np.ceil(v2 * factor / step) + 0.5,
+                     dtype=int) * step
+
+    # n : number of valid levels. If there is a cycle, e.g., [0, 90, 180,
+    # 270, 360], the grid line needs to be extended from 0 to 360, so
+    # we need to return the whole array. However, the last level (360)
+    # needs to be ignored often. In this case, so we return n=4.
+
+    n = len(levs)
+
+    # we need to check the range of values
+    # for example, -90 to 90, 0 to 360,
+
+    if factor == 1. and levs[-1] >= levs[0] + cycle:  # check for cycle
+        nv = int(cycle / step)
+        if include_last:
+            levs = levs[0] + np.arange(0, nv+1, 1) * step
+        else:
+            levs = levs[0] + np.arange(0, nv, 1) * step
+
+        n = len(levs)
+
+    return np.array(levs), n, factor
+
+
+def select_step24(v1, v2, nv, include_last=True, threshold_factor=3600):
+    v1, v2 = v1 / 15, v2 / 15
+    levs, n, factor = select_step(v1, v2, nv, hour=True,
+                                  include_last=include_last,
+                                  threshold_factor=threshold_factor)
+    return levs * 15, n, factor
+
+
+def select_step360(v1, v2, nv, include_last=True, threshold_factor=3600):
+    return select_step(v1, v2, nv, hour=False,
+                       include_last=include_last,
+                       threshold_factor=threshold_factor)
+
+
+class LocatorBase:
+    @cbook._rename_parameter("3.3", "den", "nbins")
+    def __init__(self, nbins, include_last=True):
+        self.nbins = nbins
+        self._include_last = include_last
+
+    @cbook.deprecated("3.3", alternative="nbins")
+    @property
+    def den(self):
+        return self.nbins
+
+    @den.setter
+    def den(self, v):
+        self.nbins = v
+
+    def set_params(self, nbins=None):
+        if nbins is not None:
+            self.nbins = int(nbins)
+
+
+class LocatorHMS(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step24(v1, v2, self.nbins, self._include_last)
+
+
+class LocatorHM(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step24(v1, v2, self.nbins, self._include_last,
+                             threshold_factor=60)
+
+
+class LocatorH(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step24(v1, v2, self.nbins, self._include_last,
+                             threshold_factor=1)
+
+
+class LocatorDMS(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step360(v1, v2, self.nbins, self._include_last)
+
+
+class LocatorDM(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step360(v1, v2, self.nbins, self._include_last,
+                              threshold_factor=60)
+
+
+class LocatorD(LocatorBase):
+    def __call__(self, v1, v2):
+        return select_step360(v1, v2, self.nbins, self._include_last,
+                              threshold_factor=1)
+
+
+class FormatterDMS:
+    deg_mark = r"^{\circ}"
+    min_mark = r"^{\prime}"
+    sec_mark = r"^{\prime\prime}"
+
+    fmt_d = "$%d" + deg_mark + "$"
+    fmt_ds = r"$%d.%s" + deg_mark + "$"
+
+    # %s for sign
+    fmt_d_m = r"$%s%d" + deg_mark + r"\,%02d" + min_mark + "$"
+    fmt_d_ms = r"$%s%d" + deg_mark + r"\,%02d.%s" + min_mark + "$"
+
+    fmt_d_m_partial = "$%s%d" + deg_mark + r"\,%02d" + min_mark + r"\,"
+    fmt_s_partial = "%02d" + sec_mark + "$"
+    fmt_ss_partial = "%02d.%s" + sec_mark + "$"
+
+    def _get_number_fraction(self, factor):
+        ## check for fractional numbers
+        number_fraction = None
+        # check for 60
+
+        for threshold in [1, 60, 3600]:
+            if factor <= threshold:
+                break
+
+            d = factor // threshold
+            int_log_d = int(np.floor(np.log10(d)))
+            if 10**int_log_d == d and d != 1:
+                number_fraction = int_log_d
+                factor = factor // 10**int_log_d
+                return factor, number_fraction
+
+        return factor, number_fraction
+
+    def __call__(self, direction, factor, values):
+        if len(values) == 0:
+            return []
+
+        ss = np.sign(values)
+        signs = ["-" if v < 0 else "" for v in values]
+
+        factor, number_fraction = self._get_number_fraction(factor)
+
+        values = np.abs(values)
+
+        if number_fraction is not None:
+            values, frac_part = divmod(values, 10 ** number_fraction)
+            frac_fmt = "%%0%dd" % (number_fraction,)
+            frac_str = [frac_fmt % (f1,) for f1 in frac_part]
+
+        if factor == 1:
+            if number_fraction is None:
+                return [self.fmt_d % (s * int(v),) for s, v in zip(ss, values)]
+            else:
+                return [self.fmt_ds % (s * int(v), f1)
+                        for s, v, f1 in zip(ss, values, frac_str)]
+        elif factor == 60:
+            deg_part, min_part = divmod(values, 60)
+            if number_fraction is None:
+                return [self.fmt_d_m % (s1, d1, m1)
+                        for s1, d1, m1 in zip(signs, deg_part, min_part)]
+            else:
+                return [self.fmt_d_ms % (s, d1, m1, f1)
+                        for s, d1, m1, f1
+                        in zip(signs, deg_part, min_part, frac_str)]
+
+        elif factor == 3600:
+            if ss[-1] == -1:
+                inverse_order = True
+                values = values[::-1]
+                signs = signs[::-1]
+            else:
+                inverse_order = False
+
+            l_hm_old = ""
+            r = []
+
+            deg_part, min_part_ = divmod(values, 3600)
+            min_part, sec_part = divmod(min_part_, 60)
+
+            if number_fraction is None:
+                sec_str = [self.fmt_s_partial % (s1,) for s1 in sec_part]
+            else:
+                sec_str = [self.fmt_ss_partial % (s1, f1)
+                           for s1, f1 in zip(sec_part, frac_str)]
+
+            for s, d1, m1, s1 in zip(signs, deg_part, min_part, sec_str):
+                l_hm = self.fmt_d_m_partial % (s, d1, m1)
+                if l_hm != l_hm_old:
+                    l_hm_old = l_hm
+                    l = l_hm + s1
+                else:
+                    l = "$" + s + s1
+                r.append(l)
+
+            if inverse_order:
+                return r[::-1]
+            else:
+                return r
+
+        else:  # factor > 3600.
+            return [r"$%s^{\circ}$" % (str(v),) for v in ss*values]
+
+
+class FormatterHMS(FormatterDMS):
+    deg_mark = r"^\mathrm{h}"
+    min_mark = r"^\mathrm{m}"
+    sec_mark = r"^\mathrm{s}"
+
+    fmt_d = "$%d" + deg_mark + "$"
+    fmt_ds = r"$%d.%s" + deg_mark + "$"
+
+    # %s for sign
+    fmt_d_m = r"$%s%d" + deg_mark + r"\,%02d" + min_mark+"$"
+    fmt_d_ms = r"$%s%d" + deg_mark + r"\,%02d.%s" + min_mark+"$"
+
+    fmt_d_m_partial = "$%s%d" + deg_mark + r"\,%02d" + min_mark + r"\,"
+    fmt_s_partial = "%02d" + sec_mark + "$"
+    fmt_ss_partial = "%02d.%s" + sec_mark + "$"
+
+    def __call__(self, direction, factor, values):  # hour
+        return super().__call__(direction, factor, np.asarray(values) / 15)
+
+
+class ExtremeFinderCycle(ExtremeFinderSimple):
+    # docstring inherited
+
+    def __init__(self, nx, ny,
+                 lon_cycle=360., lat_cycle=None,
+                 lon_minmax=None, lat_minmax=(-90, 90)):
+        """
+        This subclass handles the case where one or both coordinates should be
+        taken modulo 360, or be restricted to not exceed a specific range.
+
+        Parameters
+        ----------
+        nx, ny : int
+            The number of samples in each direction.
+
+        lon_cycle, lat_cycle : 360 or None
+            If not None, values in the corresponding direction are taken modulo
+            *lon_cycle* or *lat_cycle*; in theory this can be any number but
+            the implementation actually assumes that it is 360 (if not None);
+            other values give nonsensical results.
+
+            This is done by "unwrapping" the transformed grid coordinates so
+            that jumps are less than a half-cycle; then normalizing the span to
+            no more than a full cycle.
+
+            For example, if values are in the union of the [0, 2] and
+            [358, 360] intervals (typically, angles measured modulo 360), the
+            values in the second interval are normalized to [-2, 0] instead so
+            that the values now cover [-2, 2].  If values are in a range of
+            [5, 1000], this gets normalized to [5, 365].
+
+        lon_minmax, lat_minmax : (float, float) or None
+            If not None, the computed bounding box is clipped to the given
+            range in the corresponding direction.
+        """
+        self.nx, self.ny = nx, ny
+        self.lon_cycle, self.lat_cycle = lon_cycle, lat_cycle
+        self.lon_minmax = lon_minmax
+        self.lat_minmax = lat_minmax
+
+    def __call__(self, transform_xy, x1, y1, x2, y2):
+        # docstring inherited
+        x, y = np.meshgrid(
+            np.linspace(x1, x2, self.nx), np.linspace(y1, y2, self.ny))
+        lon, lat = transform_xy(np.ravel(x), np.ravel(y))
+
+        # iron out jumps, but algorithm should be improved.
+        # This is just naive way of doing and my fail for some cases.
+        # Consider replacing this with numpy.unwrap
+        # We are ignoring invalid warnings. They are triggered when
+        # comparing arrays with NaNs using > We are already handling
+        # that correctly using np.nanmin and np.nanmax
+        with np.errstate(invalid='ignore'):
+            if self.lon_cycle is not None:
+                lon0 = np.nanmin(lon)
+                lon -= 360. * ((lon - lon0) > 180.)
+            if self.lat_cycle is not None:
+                lat0 = np.nanmin(lat)
+                lat -= 360. * ((lat - lat0) > 180.)
+
+        lon_min, lon_max = np.nanmin(lon), np.nanmax(lon)
+        lat_min, lat_max = np.nanmin(lat), np.nanmax(lat)
+
+        lon_min, lon_max, lat_min, lat_max = \
+            self._add_pad(lon_min, lon_max, lat_min, lat_max)
+
+        # check cycle
+        if self.lon_cycle:
+            lon_max = min(lon_max, lon_min + self.lon_cycle)
+        if self.lat_cycle:
+            lat_max = min(lat_max, lat_min + self.lat_cycle)
+
+        if self.lon_minmax is not None:
+            min0 = self.lon_minmax[0]
+            lon_min = max(min0, lon_min)
+            max0 = self.lon_minmax[1]
+            lon_max = min(max0, lon_max)
+
+        if self.lat_minmax is not None:
+            min0 = self.lat_minmax[0]
+            lat_min = max(min0, lat_min)
+            max0 = self.lat_minmax[1]
+            lat_max = min(max0, lat_max)
+
+        return lon_min, lon_max, lat_min, lat_max

venv/Lib/site-packages/mpl_toolkits/axisartist/axes_divider.py

@@ -0,0 +1,2 @@
+from mpl_toolkits.axes_grid1.axes_divider import (
+    Divider, AxesLocator, SubplotDivider, AxesDivider, make_axes_locatable)

venv/Lib/site-packages/mpl_toolkits/axisartist/axes_grid.py

@@ -0,0 +1,18 @@
+import mpl_toolkits.axes_grid1.axes_grid as axes_grid_orig
+from .axislines import Axes
+
+
+class CbarAxes(axes_grid_orig.CbarAxesBase, Axes):
+    pass
+
+
+class Grid(axes_grid_orig.Grid):
+    _defaultAxesClass = Axes
+
+
+class ImageGrid(axes_grid_orig.ImageGrid):
+    _defaultAxesClass = Axes
+    _defaultCbarAxesClass = CbarAxes
+
+
+AxesGrid = ImageGrid

venv/Lib/site-packages/mpl_toolkits/axisartist/axes_rgb.py

@@ -0,0 +1,7 @@
+from mpl_toolkits.axes_grid1.axes_rgb import (
+    make_rgb_axes, imshow_rgb, RGBAxes as _RGBAxes)
+from .axislines import Axes
+
+
+class RGBAxes(_RGBAxes):
+    _defaultAxesClass = Axes

venv/Lib/site-packages/mpl_toolkits/axisartist/axisline_style.py

@@ -0,0 +1,153 @@
+from matplotlib.patches import _Style, FancyArrowPatch
+from matplotlib.transforms import IdentityTransform
+from matplotlib.path import Path
+import numpy as np
+
+
+class _FancyAxislineStyle:
+    class SimpleArrow(FancyArrowPatch):
+        """
+        The artist class that will be returned for SimpleArrow style.
+        """
+        _ARROW_STYLE = "->"
+
+        def __init__(self, axis_artist, line_path, transform,
+                     line_mutation_scale):
+            self._axis_artist = axis_artist
+            self._line_transform = transform
+            self._line_path = line_path
+            self._line_mutation_scale = line_mutation_scale
+
+            FancyArrowPatch.__init__(self,
+                                     path=self._line_path,
+                                     arrowstyle=self._ARROW_STYLE,
+                                     patchA=None,
+                                     patchB=None,
+                                     shrinkA=0.,
+                                     shrinkB=0.,
+                                     mutation_scale=line_mutation_scale,
+                                     mutation_aspect=None,
+                                     transform=IdentityTransform(),
+                                     )
+
+        def set_line_mutation_scale(self, scale):
+            self.set_mutation_scale(scale*self._line_mutation_scale)
+
+        def _extend_path(self, path, mutation_size=10):
+            """
+            Extend the path to make a room for drawing arrow.
+            """
+            from matplotlib.bezier import get_cos_sin
+
+            x0, y0 = path.vertices[-2]
+            x1, y1 = path.vertices[-1]
+            cost, sint = get_cos_sin(x0, y0, x1, y1)
+
+            d = mutation_size * 1.
+            x2, y2 = x1 + cost*d, y1+sint*d
+
+            if path.codes is None:
+                _path = Path(np.concatenate([path.vertices, [[x2, y2]]]))
+            else:
+                _path = Path(np.concatenate([path.vertices, [[x2, y2]]]),
+                             np.concatenate([path.codes, [Path.LINETO]]))
+
+            return _path
+
+        def set_path(self, path):
+            self._line_path = path
+
+        def draw(self, renderer):
+            """
+            Draw the axis line.
+             1) transform the path to the display coordinate.
+             2) extend the path to make a room for arrow
+             3) update the path of the FancyArrowPatch.
+             4) draw
+            """
+            path_in_disp = self._line_transform.transform_path(self._line_path)
+            mutation_size = self.get_mutation_scale()  # line_mutation_scale()
+            extended_path = self._extend_path(path_in_disp,
+                                              mutation_size=mutation_size)
+            self._path_original = extended_path
+            FancyArrowPatch.draw(self, renderer)
+
+    class FilledArrow(SimpleArrow):
+        """
+        The artist class that will be returned for SimpleArrow style.
+        """
+        _ARROW_STYLE = "-|>"
+
+
+class AxislineStyle(_Style):
+    """
+    A container class which defines style classes for AxisArtists.
+
+    An instance of any axisline style class is an callable object,
+    whose call signature is ::
+
+       __call__(self, axis_artist, path, transform)
+
+    When called, this should return an `.Artist` with the following methods::
+
+      def set_path(self, path):
+          # set the path for axisline.
+
+      def set_line_mutation_scale(self, scale):
+          # set the scale
+
+      def draw(self, renderer):
+          # draw
+    """
+
+    _style_list = {}
+
+    class _Base:
+        # The derived classes are required to be able to be initialized
+        # w/o arguments, i.e., all its argument (except self) must have
+        # the default values.
+
+        def __init__(self):
+            """
+            initialization.
+            """
+            super().__init__()
+
+        def __call__(self, axis_artist, transform):
+            """
+            Given the AxisArtist instance, and transform for the path (set_path
+            method), return the Matplotlib artist for drawing the axis line.
+            """
+            return self.new_line(axis_artist, transform)
+
+    class SimpleArrow(_Base):
+        """
+        A simple arrow.
+        """
+
+        ArrowAxisClass = _FancyAxislineStyle.SimpleArrow
+
+        def __init__(self, size=1):
+            """
+            Parameters
+            ----------
+            size : float
+                Size of the arrow as a fraction of the ticklabel size.
+            """
+
+            self.size = size
+            super().__init__()
+
+        def new_line(self, axis_artist, transform):
+
+            linepath = Path([(0, 0), (0, 1)])
+            axisline = self.ArrowAxisClass(axis_artist, linepath, transform,
+                                           line_mutation_scale=self.size)
+            return axisline
+
+    _style_list["->"] = SimpleArrow
+
+    class FilledArrow(SimpleArrow):
+        ArrowAxisClass = _FancyAxislineStyle.FilledArrow
+
+    _style_list["-|>"] = FilledArrow

venv/Lib/site-packages/mpl_toolkits/axisartist/axislines.py

@@ -0,0 +1,607 @@
+"""
+Axislines includes modified implementation of the Axes class. The
+biggest difference is that the artists responsible for drawing the axis spine,
+ticks, ticklabels and axis labels are separated out from Matplotlib's Axis
+class. Originally, this change was motivated to support curvilinear
+grid. Here are a few reasons that I came up with a new axes class:
+
+* "top" and "bottom" x-axis (or "left" and "right" y-axis) can have
+  different ticks (tick locations and labels). This is not possible
+  with the current Matplotlib, although some twin axes trick can help.
+
+* Curvilinear grid.
+
+* angled ticks.
+
+In the new axes class, xaxis and yaxis is set to not visible by
+default, and new set of artist (AxisArtist) are defined to draw axis
+line, ticks, ticklabels and axis label. Axes.axis attribute serves as
+a dictionary of these artists, i.e., ax.axis["left"] is a AxisArtist
+instance responsible to draw left y-axis. The default Axes.axis contains
+"bottom", "left", "top" and "right".
+
+AxisArtist can be considered as a container artist and
+has following children artists which will draw ticks, labels, etc.
+
+* line
+* major_ticks, major_ticklabels
+* minor_ticks, minor_ticklabels
+* offsetText
+* label
+
+Note that these are separate artists from `matplotlib.axis.Axis`, thus most
+tick-related functions in Matplotlib won't work. For example, color and
+markerwidth of the ``ax.axis["bottom"].major_ticks`` will follow those of
+Axes.xaxis unless explicitly specified.
+
+In addition to AxisArtist, the Axes will have *gridlines* attribute,
+which obviously draws grid lines. The gridlines needs to be separated
+from the axis as some gridlines can never pass any axis.
+"""
+
+import numpy as np
+
+from matplotlib import cbook, rcParams
+import matplotlib.axes as maxes
+from matplotlib.path import Path
+from mpl_toolkits.axes_grid1 import mpl_axes
+from .axisline_style import AxislineStyle
+from .axis_artist import AxisArtist, GridlinesCollection
+
+
+class AxisArtistHelper:
+    """
+    AxisArtistHelper should define
+    following method with given APIs. Note that the first axes argument
+    will be axes attribute of the caller artist.::
+
+
+        # LINE (spinal line?)
+
+        def get_line(self, axes):
+            # path : Path
+            return path
+
+        def get_line_transform(self, axes):
+            # ...
+            # trans : transform
+            return trans
+
+        # LABEL
+
+        def get_label_pos(self, axes):
+            # x, y : position
+            return (x, y), trans
+
+
+        def get_label_offset_transform(self,
+                axes,
+                pad_points, fontprops, renderer,
+                bboxes,
+                ):
+            # va : vertical alignment
+            # ha : horizontal alignment
+            # a : angle
+            return trans, va, ha, a
+
+        # TICK
+
+        def get_tick_transform(self, axes):
+            return trans
+
+        def get_tick_iterators(self, axes):
+            # iter : iterable object that yields (c, angle, l) where
+            # c, angle, l is position, tick angle, and label
+
+            return iter_major, iter_minor
+    """
+
+    class _Base:
+        """Base class for axis helper."""
+        def __init__(self):
+            self.delta1, self.delta2 = 0.00001, 0.00001
+
+        def update_lim(self, axes):
+            pass
+
+    class Fixed(_Base):
+        """Helper class for a fixed (in the axes coordinate) axis."""
+
+        _default_passthru_pt = dict(left=(0, 0),
+                                    right=(1, 0),
+                                    bottom=(0, 0),
+                                    top=(0, 1))
+
+        def __init__(self, loc, nth_coord=None):
+            """
+            nth_coord = along which coordinate value varies
+            in 2d, nth_coord = 0 ->  x axis, nth_coord = 1 -> y axis
+            """
+            cbook._check_in_list(["left", "right", "bottom", "top"], loc=loc)
+            self._loc = loc
+
+            if nth_coord is None:
+                if loc in ["left", "right"]:
+                    nth_coord = 1
+                elif loc in ["bottom", "top"]:
+                    nth_coord = 0
+
+            self.nth_coord = nth_coord
+
+            super().__init__()
+
+            self.passthru_pt = self._default_passthru_pt[loc]
+
+            _verts = np.array([[0., 0.],
+                               [1., 1.]])
+            fixed_coord = 1 - nth_coord
+            _verts[:, fixed_coord] = self.passthru_pt[fixed_coord]
+
+            # axis line in transAxes
+            self._path = Path(_verts)
+
+        def get_nth_coord(self):
+            return self.nth_coord
+
+        # LINE
+
+        def get_line(self, axes):
+            return self._path
+
+        def get_line_transform(self, axes):
+            return axes.transAxes
+
+        # LABEL
+
+        def get_axislabel_transform(self, axes):
+            return axes.transAxes
+
+        def get_axislabel_pos_angle(self, axes):
+            """
+            Return the label reference position in transAxes.
+
+            get_label_transform() returns a transform of (transAxes+offset)
+            """
+            return dict(left=((0., 0.5), 90),  # (position, angle_tangent)
+                        right=((1., 0.5), 90),
+                        bottom=((0.5, 0.), 0),
+                        top=((0.5, 1.), 0))[self._loc]
+
+        # TICK
+
+        def get_tick_transform(self, axes):
+            return [axes.get_xaxis_transform(),
+                    axes.get_yaxis_transform()][self.nth_coord]
+
+    class Floating(_Base):
+
+        def __init__(self, nth_coord, value):
+            self.nth_coord = nth_coord
+            self._value = value
+            super().__init__()
+
+        def get_nth_coord(self):
+            return self.nth_coord
+
+        def get_line(self, axes):
+            raise RuntimeError(
+                "get_line method should be defined by the derived class")
+
+
+class AxisArtistHelperRectlinear:
+
+    class Fixed(AxisArtistHelper.Fixed):
+
+        def __init__(self, axes, loc, nth_coord=None):
+            """
+            nth_coord = along which coordinate value varies
+            in 2d, nth_coord = 0 ->  x axis, nth_coord = 1 -> y axis
+            """
+            super().__init__(loc, nth_coord)
+            self.axis = [axes.xaxis, axes.yaxis][self.nth_coord]
+
+        # TICK
+
+        def get_tick_iterators(self, axes):
+            """tick_loc, tick_angle, tick_label"""
+
+            loc = self._loc
+
+            if loc in ["bottom", "top"]:
+                angle_normal, angle_tangent = 90, 0
+            else:
+                angle_normal, angle_tangent = 0, 90
+
+            major = self.axis.major
+            majorLocs = major.locator()
+            majorLabels = major.formatter.format_ticks(majorLocs)
+
+            minor = self.axis.minor
+            minorLocs = minor.locator()
+            minorLabels = minor.formatter.format_ticks(minorLocs)
+
+            tick_to_axes = self.get_tick_transform(axes) - axes.transAxes
+
+            def _f(locs, labels):
+                for x, l in zip(locs, labels):
+
+                    c = list(self.passthru_pt)  # copy
+                    c[self.nth_coord] = x
+
+                    # check if the tick point is inside axes
+                    c2 = tick_to_axes.transform(c)
+                    if (0 - self.delta1
+                            <= c2[self.nth_coord]
+                            <= 1 + self.delta2):
+                        yield c, angle_normal, angle_tangent, l
+
+            return _f(majorLocs, majorLabels), _f(minorLocs, minorLabels)
+
+    class Floating(AxisArtistHelper.Floating):
+        def __init__(self, axes, nth_coord,
+                     passingthrough_point, axis_direction="bottom"):
+            super().__init__(nth_coord, passingthrough_point)
+            self._axis_direction = axis_direction
+            self.axis = [axes.xaxis, axes.yaxis][self.nth_coord]
+
+        def get_line(self, axes):
+            _verts = np.array([[0., 0.],
+                               [1., 1.]])
+
+            fixed_coord = 1 - self.nth_coord
+            data_to_axes = axes.transData - axes.transAxes
+            p = data_to_axes.transform([self._value, self._value])
+            _verts[:, fixed_coord] = p[fixed_coord]
+
+            return Path(_verts)
+
+        def get_line_transform(self, axes):
+            return axes.transAxes
+
+        def get_axislabel_transform(self, axes):
+            return axes.transAxes
+
+        def get_axislabel_pos_angle(self, axes):
+            """
+            Return the label reference position in transAxes.
+
+            get_label_transform() returns a transform of (transAxes+offset)
+            """
+            angle = [0, 90][self.nth_coord]
+            _verts = [0.5, 0.5]
+            fixed_coord = 1 - self.nth_coord
+            data_to_axes = axes.transData - axes.transAxes
+            p = data_to_axes.transform([self._value, self._value])
+            _verts[fixed_coord] = p[fixed_coord]
+            if 0 <= _verts[fixed_coord] <= 1:
+                return _verts, angle
+            else:
+                return None, None
+
+        def get_tick_transform(self, axes):
+            return axes.transData
+
+        def get_tick_iterators(self, axes):
+            """tick_loc, tick_angle, tick_label"""
+            if self.nth_coord == 0:
+                angle_normal, angle_tangent = 90, 0
+            else:
+                angle_normal, angle_tangent = 0, 90
+
+            major = self.axis.major
+            majorLocs = major.locator()
+            majorLabels = major.formatter.format_ticks(majorLocs)
+
+            minor = self.axis.minor
+            minorLocs = minor.locator()
+            minorLabels = minor.formatter.format_ticks(minorLocs)
+
+            data_to_axes = axes.transData - axes.transAxes
+
+            def _f(locs, labels):
+                for x, l in zip(locs, labels):
+                    c = [self._value, self._value]
+                    c[self.nth_coord] = x
+                    c1, c2 = data_to_axes.transform(c)
+                    if (0 <= c1 <= 1 and 0 <= c2 <= 1
+                            and 0 - self.delta1
+                                <= [c1, c2][self.nth_coord]
+                                <= 1 + self.delta2):
+                        yield c, angle_normal, angle_tangent, l
+
+            return _f(majorLocs, majorLabels), _f(minorLocs, minorLabels)
+
+
+class GridHelperBase:
+
+    def __init__(self):
+        self._force_update = True
+        self._old_limits = None
+        super().__init__()
+
+    def update_lim(self, axes):
+        x1, x2 = axes.get_xlim()
+        y1, y2 = axes.get_ylim()
+
+        if self._force_update or self._old_limits != (x1, x2, y1, y2):
+            self._update(x1, x2, y1, y2)
+            self._force_update = False
+            self._old_limits = (x1, x2, y1, y2)
+
+    def _update(self, x1, x2, y1, y2):
+        pass
+
+    def invalidate(self):
+        self._force_update = True
+
+    def valid(self):
+        return not self._force_update
+
+    def get_gridlines(self, which, axis):
+        """
+        Return list of grid lines as a list of paths (list of points).
+
+        *which* : "major" or "minor"
+        *axis* : "both", "x" or "y"
+        """
+        return []
+
+    def new_gridlines(self, ax):
+        """
+        Create and return a new GridlineCollection instance.
+
+        *which* : "major" or "minor"
+        *axis* : "both", "x" or "y"
+
+        """
+        gridlines = GridlinesCollection(None, transform=ax.transData,
+                                        colors=rcParams['grid.color'],
+                                        linestyles=rcParams['grid.linestyle'],
+                                        linewidths=rcParams['grid.linewidth'])
+        ax._set_artist_props(gridlines)
+        gridlines.set_grid_helper(self)
+
+        ax.axes._set_artist_props(gridlines)
+        # gridlines.set_clip_path(self.axes.patch)
+        # set_clip_path need to be deferred after Axes.cla is completed.
+        # It is done inside the cla.
+
+        return gridlines
+
+
+class GridHelperRectlinear(GridHelperBase):
+
+    def __init__(self, axes):
+        super().__init__()
+        self.axes = axes
+
+    def new_fixed_axis(self, loc,
+                       nth_coord=None,
+                       axis_direction=None,
+                       offset=None,
+                       axes=None,
+                       ):
+
+        if axes is None:
+            cbook._warn_external(
+                "'new_fixed_axis' explicitly requires the axes keyword.")
+            axes = self.axes
+
+        _helper = AxisArtistHelperRectlinear.Fixed(axes, loc, nth_coord)
+
+        if axis_direction is None:
+            axis_direction = loc
+        axisline = AxisArtist(axes, _helper, offset=offset,
+                              axis_direction=axis_direction,
+                              )
+
+        return axisline
+
+    def new_floating_axis(self, nth_coord, value,
+                          axis_direction="bottom",
+                          axes=None,
+                          ):
+
+        if axes is None:
+            cbook._warn_external(
+                "'new_floating_axis' explicitly requires the axes keyword.")
+            axes = self.axes
+
+        _helper = AxisArtistHelperRectlinear.Floating(
+            axes, nth_coord, value, axis_direction)
+
+        axisline = AxisArtist(axes, _helper)
+
+        axisline.line.set_clip_on(True)
+        axisline.line.set_clip_box(axisline.axes.bbox)
+        return axisline
+
+    def get_gridlines(self, which="major", axis="both"):
+        """
+        Return list of gridline coordinates in data coordinates.
+
+        *which* : "major" or "minor"
+        *axis* : "both", "x" or "y"
+        """
+        gridlines = []
+
+        if axis in ["both", "x"]:
+            locs = []
+            y1, y2 = self.axes.get_ylim()
+            if which in ["both", "major"]:
+                locs.extend(self.axes.xaxis.major.locator())
+            if which in ["both", "minor"]:
+                locs.extend(self.axes.xaxis.minor.locator())
+
+            for x in locs:
+                gridlines.append([[x, x], [y1, y2]])
+
+        if axis in ["both", "y"]:
+            x1, x2 = self.axes.get_xlim()
+            locs = []
+            if self.axes.yaxis._gridOnMajor:
+                locs.extend(self.axes.yaxis.major.locator())
+            if self.axes.yaxis._gridOnMinor:
+                locs.extend(self.axes.yaxis.minor.locator())
+
+            for y in locs:
+                gridlines.append([[x1, x2], [y, y]])
+
+        return gridlines
+
+
+class Axes(maxes.Axes):
+
+    def __call__(self, *args, **kwargs):
+        return maxes.Axes.axis(self.axes, *args, **kwargs)
+
+    def __init__(self, *args, grid_helper=None, **kwargs):
+        self._axisline_on = True
+        self._grid_helper = (grid_helper if grid_helper
+                             else GridHelperRectlinear(self))
+        super().__init__(*args, **kwargs)
+        self.toggle_axisline(True)
+
+    def toggle_axisline(self, b=None):
+        if b is None:
+            b = not self._axisline_on
+        if b:
+            self._axisline_on = True
+            for s in self.spines.values():
+                s.set_visible(False)
+            self.xaxis.set_visible(False)
+            self.yaxis.set_visible(False)
+        else:
+            self._axisline_on = False
+            for s in self.spines.values():
+                s.set_visible(True)
+            self.xaxis.set_visible(True)
+            self.yaxis.set_visible(True)
+
+    def _init_axis_artists(self, axes=None):
+        if axes is None:
+            axes = self
+
+        self._axislines = mpl_axes.Axes.AxisDict(self)
+        new_fixed_axis = self.get_grid_helper().new_fixed_axis
+        for loc in ["bottom", "top", "left", "right"]:
+            self._axislines[loc] = new_fixed_axis(loc=loc, axes=axes,
+                                                  axis_direction=loc)
+
+        for axisline in [self._axislines["top"], self._axislines["right"]]:
+            axisline.label.set_visible(False)
+            axisline.major_ticklabels.set_visible(False)
+            axisline.minor_ticklabels.set_visible(False)
+
+    @property
+    def axis(self):
+        return self._axislines
+
+    def new_gridlines(self, grid_helper=None):
+        """
+        Create and return a new GridlineCollection instance.
+
+        *which* : "major" or "minor"
+        *axis* : "both", "x" or "y"
+
+        """
+        if grid_helper is None:
+            grid_helper = self.get_grid_helper()
+
+        gridlines = grid_helper.new_gridlines(self)
+        return gridlines
+
+    def _init_gridlines(self, grid_helper=None):
+        # It is done inside the cla.
+        self.gridlines = self.new_gridlines(grid_helper)
+
+    def cla(self):
+        # gridlines need to b created before cla() since cla calls grid()
+        self._init_gridlines()
+        super().cla()
+
+        # the clip_path should be set after Axes.cla() since that's
+        # when a patch is created.
+        self.gridlines.set_clip_path(self.axes.patch)
+
+        self._init_axis_artists()
+
+    def get_grid_helper(self):
+        return self._grid_helper
+
+    def grid(self, b=None, which='major', axis="both", **kwargs):
+        """
+        Toggle the gridlines, and optionally set the properties of the lines.
+        """
+        # their are some discrepancy between the behavior of grid in
+        # axes_grid and the original mpl's grid, because axes_grid
+        # explicitly set the visibility of the gridlines.
+        super().grid(b, which=which, axis=axis, **kwargs)
+        if not self._axisline_on:
+            return
+        if b is None:
+            b = (self.axes.xaxis._gridOnMinor
+                 or self.axes.xaxis._gridOnMajor
+                 or self.axes.yaxis._gridOnMinor
+                 or self.axes.yaxis._gridOnMajor)
+        self.gridlines.set(which=which, axis=axis, visible=b)
+        self.gridlines.set(**kwargs)
+
+    def get_children(self):
+        if self._axisline_on:
+            children = [*self._axislines.values(), self.gridlines]
+        else:
+            children = []
+        children.extend(super().get_children())
+        return children
+
+    def invalidate_grid_helper(self):
+        self._grid_helper.invalidate()
+
+    def new_fixed_axis(self, loc, offset=None):
+        gh = self.get_grid_helper()
+        axis = gh.new_fixed_axis(loc,
+                                 nth_coord=None,
+                                 axis_direction=None,
+                                 offset=offset,
+                                 axes=self,
+                                 )
+        return axis
+
+    def new_floating_axis(self, nth_coord, value, axis_direction="bottom"):
+        gh = self.get_grid_helper()
+        axis = gh.new_floating_axis(nth_coord, value,
+                                    axis_direction=axis_direction,
+                                    axes=self)
+        return axis
+
+
+Subplot = maxes.subplot_class_factory(Axes)
+
+
+class AxesZero(Axes):
+
+    def _init_axis_artists(self):
+        super()._init_axis_artists()
+
+        new_floating_axis = self._grid_helper.new_floating_axis
+        xaxis_zero = new_floating_axis(nth_coord=0,
+                                       value=0.,
+                                       axis_direction="bottom",
+                                       axes=self)
+
+        xaxis_zero.line.set_clip_path(self.patch)
+        xaxis_zero.set_visible(False)
+        self._axislines["xzero"] = xaxis_zero
+
+        yaxis_zero = new_floating_axis(nth_coord=1,
+                                       value=0.,
+                                       axis_direction="left",
+                                       axes=self)
+
+        yaxis_zero.line.set_clip_path(self.patch)
+        yaxis_zero.set_visible(False)
+        self._axislines["yzero"] = yaxis_zero
+
+
+SubplotZero = maxes.subplot_class_factory(AxesZero)

venv/Lib/site-packages/mpl_toolkits/axisartist/clip_path.py

@@ -0,0 +1,118 @@
+import numpy as np
+from math import degrees
+from matplotlib import cbook
+import math
+
+
+def atan2(dy, dx):
+    if dx == 0 and dy == 0:
+        cbook._warn_external("dx and dy are 0")
+        return 0
+    else:
+        return math.atan2(dy, dx)
+
+
+# FIXME : The current algorithm seems to return incorrect angle when the line
+# ends at the boundary.
+def clip(xlines, ylines, x0, clip="right", xdir=True, ydir=True):
+
+    clipped_xlines = []
+    clipped_ylines = []
+
+    _pos_angles = []
+
+    xsign = 1 if xdir else -1
+    ysign = 1 if ydir else -1
+
+    for x, y in zip(xlines, ylines):
+
+        if clip in ["up", "right"]:
+            b = (x < x0).astype("i")
+            db = b[1:] - b[:-1]
+        else:
+            b = (x > x0).astype("i")
+            db = b[1:] - b[:-1]
+
+        if b[0]:
+            ns = 0
+        else:
+            ns = -1
+        segx, segy = [], []
+        for (i,) in np.argwhere(db):
+            c = db[i]
+            if c == -1:
+                dx = (x0 - x[i])
+                dy = (y[i+1] - y[i]) * (dx / (x[i+1] - x[i]))
+                y0 = y[i] + dy
+                clipped_xlines.append(np.concatenate([segx, x[ns:i+1], [x0]]))
+                clipped_ylines.append(np.concatenate([segy, y[ns:i+1], [y0]]))
+                ns = -1
+                segx, segy = [], []
+
+                if dx == 0. and dy == 0:
+                    dx = x[i+1] - x[i]
+                    dy = y[i+1] - y[i]
+
+                a = degrees(atan2(ysign*dy, xsign*dx))
+                _pos_angles.append((x0, y0, a))
+
+            elif c == 1:
+                dx = (x0 - x[i])
+                dy = (y[i+1] - y[i]) * (dx / (x[i+1] - x[i]))
+                y0 = y[i] + dy
+                segx, segy = [x0], [y0]
+                ns = i+1
+
+                if dx == 0. and dy == 0:
+                    dx = x[i+1] - x[i]
+                    dy = y[i+1] - y[i]
+
+                a = degrees(atan2(ysign*dy, xsign*dx))
+                _pos_angles.append((x0, y0, a))
+
+        if ns != -1:
+            clipped_xlines.append(np.concatenate([segx, x[ns:]]))
+            clipped_ylines.append(np.concatenate([segy, y[ns:]]))
+
+    return clipped_xlines, clipped_ylines, _pos_angles
+
+
+def clip_line_to_rect(xline, yline, bbox):
+
+    x0, y0, x1, y1 = bbox.extents
+
+    xdir = x1 > x0
+    ydir = y1 > y0
+
+    if x1 > x0:
+        lx1, ly1, c_right_ = clip([xline], [yline], x1,
+                                  clip="right", xdir=xdir, ydir=ydir)
+        lx2, ly2, c_left_ = clip(lx1, ly1, x0,
+                                 clip="left", xdir=xdir, ydir=ydir)
+    else:
+        lx1, ly1, c_right_ = clip([xline], [yline], x0,
+                                  clip="right", xdir=xdir, ydir=ydir)
+        lx2, ly2, c_left_ = clip(lx1, ly1, x1,
+                                 clip="left", xdir=xdir, ydir=ydir)
+
+    if y1 > y0:
+        ly3, lx3, c_top_ = clip(ly2, lx2, y1,
+                                clip="right", xdir=ydir, ydir=xdir)
+        ly4, lx4, c_bottom_ = clip(ly3, lx3, y0,
+                                   clip="left", xdir=ydir, ydir=xdir)
+    else:
+        ly3, lx3, c_top_ = clip(ly2, lx2, y0,
+                                clip="right", xdir=ydir, ydir=xdir)
+        ly4, lx4, c_bottom_ = clip(ly3, lx3, y1,
+                                   clip="left", xdir=ydir, ydir=xdir)
+
+    c_left = [((x, y), (a + 90) % 180 - 90) for x, y, a in c_left_
+              if bbox.containsy(y)]
+    c_bottom = [((x, y), (90 - a) % 180) for y, x, a in c_bottom_
+                if bbox.containsx(x)]
+    c_right = [((x, y), (a + 90) % 180 + 90) for x, y, a in c_right_
+               if bbox.containsy(y)]
+    c_top = [((x, y), (90 - a) % 180 + 180) for y, x, a in c_top_
+             if bbox.containsx(x)]
+
+    return list(zip(lx4, ly4)), [c_left, c_bottom, c_right, c_top]

venv/Lib/site-packages/mpl_toolkits/axisartist/floating_axes.py

@@ -0,0 +1,372 @@
+"""
+An experimental support for curvilinear grid.
+"""
+
+# TODO :
+# see if tick_iterator method can be simplified by reusing the parent method.
+
+import functools
+
+import numpy as np
+
+import matplotlib.patches as mpatches
+from matplotlib.path import Path
+import matplotlib.axes as maxes
+
+from mpl_toolkits.axes_grid1.parasite_axes import host_axes_class_factory
+
+from . import axislines, grid_helper_curvelinear
+from .axis_artist import AxisArtist
+from .grid_finder import ExtremeFinderSimple
+
+
+class FloatingAxisArtistHelper(
+        grid_helper_curvelinear.FloatingAxisArtistHelper):
+    pass
+
+
+class FixedAxisArtistHelper(grid_helper_curvelinear.FloatingAxisArtistHelper):
+
+    def __init__(self, grid_helper, side, nth_coord_ticks=None):
+        """
+        nth_coord = along which coordinate value varies.
+         nth_coord = 0 ->  x axis, nth_coord = 1 -> y axis
+        """
+        value, nth_coord = grid_helper.get_data_boundary(side)
+        super().__init__(grid_helper, nth_coord, value, axis_direction=side)
+        if nth_coord_ticks is None:
+            nth_coord_ticks = nth_coord
+        self.nth_coord_ticks = nth_coord_ticks
+
+        self.value = value
+        self.grid_helper = grid_helper
+        self._side = side
+
+    def update_lim(self, axes):
+        self.grid_helper.update_lim(axes)
+        self.grid_info = self.grid_helper.grid_info
+
+    def get_tick_iterators(self, axes):
+        """tick_loc, tick_angle, tick_label, (optionally) tick_label"""
+
+        grid_finder = self.grid_helper.grid_finder
+
+        lat_levs, lat_n, lat_factor = self.grid_info["lat_info"]
+        lon_levs, lon_n, lon_factor = self.grid_info["lon_info"]
+
+        lon_levs, lat_levs = np.asarray(lon_levs), np.asarray(lat_levs)
+        if lat_factor is not None:
+            yy0 = lat_levs / lat_factor
+            dy = 0.001 / lat_factor
+        else:
+            yy0 = lat_levs
+            dy = 0.001
+
+        if lon_factor is not None:
+            xx0 = lon_levs / lon_factor
+            dx = 0.001 / lon_factor
+        else:
+            xx0 = lon_levs
+            dx = 0.001
+
+        extremes = self.grid_helper._extremes
+        xmin, xmax = sorted(extremes[:2])
+        ymin, ymax = sorted(extremes[2:])
+
+        def transform_xy(x, y):
+            x1, y1 = grid_finder.transform_xy(x, y)
+            x2, y2 = axes.transData.transform(np.array([x1, y1]).T).T
+            return x2, y2
+
+        if self.nth_coord == 0:
+            mask = (ymin <= yy0) & (yy0 <= ymax)
+            yy0 = yy0[mask]
+            xx0 = np.full_like(yy0, self.value)
+            xx1, yy1 = transform_xy(xx0, yy0)
+
+            xx00 = xx0.astype(float, copy=True)
+            xx00[xx0 + dx > xmax] -= dx
+            xx1a, yy1a = transform_xy(xx00, yy0)
+            xx1b, yy1b = transform_xy(xx00 + dx, yy0)
+
+            yy00 = yy0.astype(float, copy=True)
+            yy00[yy0 + dy > ymax] -= dy
+            xx2a, yy2a = transform_xy(xx0, yy00)
+            xx2b, yy2b = transform_xy(xx0, yy00 + dy)
+
+            labels = self.grid_info["lat_labels"]
+            labels = [l for l, m in zip(labels, mask) if m]
+
+        elif self.nth_coord == 1:
+            mask = (xmin <= xx0) & (xx0 <= xmax)
+            xx0 = xx0[mask]
+            yy0 = np.full_like(xx0, self.value)
+            xx1, yy1 = transform_xy(xx0, yy0)
+
+            yy00 = yy0.astype(float, copy=True)
+            yy00[yy0 + dy > ymax] -= dy
+            xx1a, yy1a = transform_xy(xx0, yy00)
+            xx1b, yy1b = transform_xy(xx0, yy00 + dy)
+
+            xx00 = xx0.astype(float, copy=True)
+            xx00[xx0 + dx > xmax] -= dx
+            xx2a, yy2a = transform_xy(xx00, yy0)
+            xx2b, yy2b = transform_xy(xx00 + dx, yy0)
+
+            labels = self.grid_info["lon_labels"]
+            labels = [l for l, m in zip(labels, mask) if m]
+
+        def f1():
+            dd = np.arctan2(yy1b - yy1a, xx1b - xx1a)  # angle normal
+            dd2 = np.arctan2(yy2b - yy2a, xx2b - xx2a)  # angle tangent
+            mm = (yy1b - yy1a == 0) & (xx1b - xx1a == 0)  # mask not defined dd
+            dd[mm] = dd2[mm] + np.pi / 2
+
+            tick_to_axes = self.get_tick_transform(axes) - axes.transAxes
+            for x, y, d, d2, lab in zip(xx1, yy1, dd, dd2, labels):
+                c2 = tick_to_axes.transform((x, y))
+                delta = 0.00001
+                if 0-delta <= c2[0] <= 1+delta and 0-delta <= c2[1] <= 1+delta:
+                    d1, d2 = np.rad2deg([d, d2])
+                    yield [x, y], d1, d2, lab
+
+        return f1(), iter([])
+
+    def get_line(self, axes):
+        self.update_lim(axes)
+        k, v = dict(left=("lon_lines0", 0),
+                    right=("lon_lines0", 1),
+                    bottom=("lat_lines0", 0),
+                    top=("lat_lines0", 1))[self._side]
+        xx, yy = self.grid_info[k][v]
+        return Path(np.column_stack([xx, yy]))
+
+
+class ExtremeFinderFixed(ExtremeFinderSimple):
+    # docstring inherited
+
+    def __init__(self, extremes):
+        """
+        This subclass always returns the same bounding box.
+
+        Parameters
+        ----------
+        extremes : (float, float, float, float)
+            The bounding box that this helper always returns.
+        """
+        self._extremes = extremes
+
+    def __call__(self, transform_xy, x1, y1, x2, y2):
+        # docstring inherited
+        return self._extremes
+
+
+class GridHelperCurveLinear(grid_helper_curvelinear.GridHelperCurveLinear):
+
+    def __init__(self, aux_trans, extremes,
+                 grid_locator1=None,
+                 grid_locator2=None,
+                 tick_formatter1=None,
+                 tick_formatter2=None):
+        # docstring inherited
+        self._extremes = extremes
+        extreme_finder = ExtremeFinderFixed(extremes)
+        super().__init__(aux_trans,
+                         extreme_finder,
+                         grid_locator1=grid_locator1,
+                         grid_locator2=grid_locator2,
+                         tick_formatter1=tick_formatter1,
+                         tick_formatter2=tick_formatter2)
+
+    def get_data_boundary(self, side):
+        """
+        Return v=0, nth=1.
+        """
+        lon1, lon2, lat1, lat2 = self._extremes
+        return dict(left=(lon1, 0),
+                    right=(lon2, 0),
+                    bottom=(lat1, 1),
+                    top=(lat2, 1))[side]
+
+    def new_fixed_axis(self, loc,
+                       nth_coord=None,
+                       axis_direction=None,
+                       offset=None,
+                       axes=None):
+        if axes is None:
+            axes = self.axes
+        if axis_direction is None:
+            axis_direction = loc
+        # This is not the same as the FixedAxisArtistHelper class used by
+        # grid_helper_curvelinear.GridHelperCurveLinear.new_fixed_axis!
+        _helper = FixedAxisArtistHelper(
+            self, loc, nth_coord_ticks=nth_coord)
+        axisline = AxisArtist(axes, _helper, axis_direction=axis_direction)
+        # Perhaps should be moved to the base class?
+        axisline.line.set_clip_on(True)
+        axisline.line.set_clip_box(axisline.axes.bbox)
+        return axisline
+
+    # new_floating_axis will inherit the grid_helper's extremes.
+
+    # def new_floating_axis(self, nth_coord,
+    #                       value,
+    #                       axes=None,
+    #                       axis_direction="bottom"
+    #                       ):
+
+    #     axis = super(GridHelperCurveLinear,
+    #                  self).new_floating_axis(nth_coord,
+    #                                          value, axes=axes,
+    #                                          axis_direction=axis_direction)
+
+    #     # set extreme values of the axis helper
+    #     if nth_coord == 1:
+    #         axis.get_helper().set_extremes(*self._extremes[:2])
+    #     elif nth_coord == 0:
+    #         axis.get_helper().set_extremes(*self._extremes[2:])
+
+    #     return axis
+
+    def _update_grid(self, x1, y1, x2, y2):
+        if self.grid_info is None:
+            self.grid_info = dict()
+
+        grid_info = self.grid_info
+
+        grid_finder = self.grid_finder
+        extremes = grid_finder.extreme_finder(grid_finder.inv_transform_xy,
+                                              x1, y1, x2, y2)
+
+        lon_min, lon_max = sorted(extremes[:2])
+        lat_min, lat_max = sorted(extremes[2:])
+        lon_levs, lon_n, lon_factor = \
+            grid_finder.grid_locator1(lon_min, lon_max)
+        lat_levs, lat_n, lat_factor = \
+            grid_finder.grid_locator2(lat_min, lat_max)
+        grid_info["extremes"] = lon_min, lon_max, lat_min, lat_max  # extremes
+
+        grid_info["lon_info"] = lon_levs, lon_n, lon_factor
+        grid_info["lat_info"] = lat_levs, lat_n, lat_factor
+
+        grid_info["lon_labels"] = grid_finder.tick_formatter1("bottom",
+                                                              lon_factor,
+                                                              lon_levs)
+
+        grid_info["lat_labels"] = grid_finder.tick_formatter2("bottom",
+                                                              lat_factor,
+                                                              lat_levs)
+
+        if lon_factor is None:
+            lon_values = np.asarray(lon_levs[:lon_n])
+        else:
+            lon_values = np.asarray(lon_levs[:lon_n]/lon_factor)
+        if lat_factor is None:
+            lat_values = np.asarray(lat_levs[:lat_n])
+        else:
+            lat_values = np.asarray(lat_levs[:lat_n]/lat_factor)
+
+        lon_lines, lat_lines = grid_finder._get_raw_grid_lines(
+            lon_values[(lon_min < lon_values) & (lon_values < lon_max)],
+            lat_values[(lat_min < lat_values) & (lat_values < lat_max)],
+            lon_min, lon_max, lat_min, lat_max)
+
+        grid_info["lon_lines"] = lon_lines
+        grid_info["lat_lines"] = lat_lines
+
+        lon_lines, lat_lines = grid_finder._get_raw_grid_lines(
+            # lon_min, lon_max, lat_min, lat_max)
+            extremes[:2], extremes[2:], *extremes)
+
+        grid_info["lon_lines0"] = lon_lines
+        grid_info["lat_lines0"] = lat_lines
+
+    def get_gridlines(self, which="major", axis="both"):
+        grid_lines = []
+        if axis in ["both", "x"]:
+            grid_lines.extend(self.grid_info["lon_lines"])
+        if axis in ["both", "y"]:
+            grid_lines.extend(self.grid_info["lat_lines"])
+        return grid_lines
+
+    def get_boundary(self):
+        """
+        Return (N, 2) array of (x, y) coordinate of the boundary.
+        """
+        x0, x1, y0, y1 = self._extremes
+        tr = self._aux_trans
+
+        xx = np.linspace(x0, x1, 100)
+        yy0 = np.full_like(xx, y0)
+        yy1 = np.full_like(xx, y1)
+        yy = np.linspace(y0, y1, 100)
+        xx0 = np.full_like(yy, x0)
+        xx1 = np.full_like(yy, x1)
+
+        xxx = np.concatenate([xx[:-1], xx1[:-1], xx[-1:0:-1], xx0])
+        yyy = np.concatenate([yy0[:-1], yy[:-1], yy1[:-1], yy[::-1]])
+        t = tr.transform(np.array([xxx, yyy]).transpose())
+
+        return t
+
+
+class FloatingAxesBase:
+
+    def __init__(self, *args, **kwargs):
+        grid_helper = kwargs.get("grid_helper", None)
+        if grid_helper is None:
+            raise ValueError("FloatingAxes requires grid_helper argument")
+        if not hasattr(grid_helper, "get_boundary"):
+            raise ValueError("grid_helper must implement get_boundary method")
+
+        self._axes_class_floating.__init__(self, *args, **kwargs)
+
+        self.set_aspect(1.)
+        self.adjust_axes_lim()
+
+    def _gen_axes_patch(self):
+        # docstring inherited
+        grid_helper = self.get_grid_helper()
+        t = grid_helper.get_boundary()
+        return mpatches.Polygon(t)
+
+    def cla(self):
+        self._axes_class_floating.cla(self)
+        # HostAxes.cla(self)
+        self.patch.set_transform(self.transData)
+
+        patch = self._axes_class_floating._gen_axes_patch(self)
+        patch.set_figure(self.figure)
+        patch.set_visible(False)
+        patch.set_transform(self.transAxes)
+
+        self.patch.set_clip_path(patch)
+        self.gridlines.set_clip_path(patch)
+
+        self._original_patch = patch
+
+    def adjust_axes_lim(self):
+        grid_helper = self.get_grid_helper()
+        t = grid_helper.get_boundary()
+        x, y = t[:, 0], t[:, 1]
+
+        xmin, xmax = min(x), max(x)
+        ymin, ymax = min(y), max(y)
+
+        dx = (xmax-xmin) / 100
+        dy = (ymax-ymin) / 100
+
+        self.set_xlim(xmin-dx, xmax+dx)
+        self.set_ylim(ymin-dy, ymax+dy)
+
+
+@functools.lru_cache(None)
+def floatingaxes_class_factory(axes_class):
+    return type("Floating %s" % axes_class.__name__,
+                (FloatingAxesBase, axes_class),
+                {'_axes_class_floating': axes_class})
+
+
+FloatingAxes = floatingaxes_class_factory(
+    host_axes_class_factory(axislines.Axes))
+FloatingSubplot = maxes.subplot_class_factory(FloatingAxes)

venv/Lib/site-packages/mpl_toolkits/axisartist/grid_finder.py

@@ -0,0 +1,304 @@
+import numpy as np
+
+from matplotlib import cbook, ticker as mticker
+from matplotlib.transforms import Bbox, Transform
+from .clip_path import clip_line_to_rect
+
+
+def _deprecate_factor_none(factor):
+    # After the deprecation period, calls to _deprecate_factor_none can just be
+    # removed.
+    if factor is None:
+        cbook.warn_deprecated(
+            "3.2", message="factor=None is deprecated since %(since)s and "
+            "support will be removed %(removal)s; use/return factor=1 instead")
+        factor = 1
+    return factor
+
+
+class ExtremeFinderSimple:
+    """
+    A helper class to figure out the range of grid lines that need to be drawn.
+    """
+
+    def __init__(self, nx, ny):
+        """
+        Parameters
+        ----------
+        nx, ny : int
+            The number of samples in each direction.
+        """
+        self.nx = nx
+        self.ny = ny
+
+    def __call__(self, transform_xy, x1, y1, x2, y2):
+        """
+        Compute an approximation of the bounding box obtained by applying
+        *transform_xy* to the box delimited by ``(x1, y1, x2, y2)``.
+
+        The intended use is to have ``(x1, y1, x2, y2)`` in axes coordinates,
+        and have *transform_xy* be the transform from axes coordinates to data
+        coordinates; this method then returns the range of data coordinates
+        that span the actual axes.
+
+        The computation is done by sampling ``nx * ny`` equispaced points in
+        the ``(x1, y1, x2, y2)`` box and finding the resulting points with
+        extremal coordinates; then adding some padding to take into account the
+        finite sampling.
+
+        As each sampling step covers a relative range of *1/nx* or *1/ny*,
+        the padding is computed by expanding the span covered by the extremal
+        coordinates by these fractions.
+        """
+        x, y = np.meshgrid(
+            np.linspace(x1, x2, self.nx), np.linspace(y1, y2, self.ny))
+        xt, yt = transform_xy(np.ravel(x), np.ravel(y))
+        return self._add_pad(xt.min(), xt.max(), yt.min(), yt.max())
+
+    def _add_pad(self, x_min, x_max, y_min, y_max):
+        """Perform the padding mentioned in `__call__`."""
+        dx = (x_max - x_min) / self.nx
+        dy = (y_max - y_min) / self.ny
+        return x_min - dx, x_max + dx, y_min - dy, y_max + dy
+
+
+class GridFinder:
+    def __init__(self,
+                 transform,
+                 extreme_finder=None,
+                 grid_locator1=None,
+                 grid_locator2=None,
+                 tick_formatter1=None,
+                 tick_formatter2=None):
+        """
+        transform : transform from the image coordinate (which will be
+        the transData of the axes to the world coordinate.
+
+        or transform = (transform_xy, inv_transform_xy)
+
+        locator1, locator2 : grid locator for 1st and 2nd axis.
+        """
+        if extreme_finder is None:
+            extreme_finder = ExtremeFinderSimple(20, 20)
+        if grid_locator1 is None:
+            grid_locator1 = MaxNLocator()
+        if grid_locator2 is None:
+            grid_locator2 = MaxNLocator()
+        if tick_formatter1 is None:
+            tick_formatter1 = FormatterPrettyPrint()
+        if tick_formatter2 is None:
+            tick_formatter2 = FormatterPrettyPrint()
+        self.extreme_finder = extreme_finder
+        self.grid_locator1 = grid_locator1
+        self.grid_locator2 = grid_locator2
+        self.tick_formatter1 = tick_formatter1
+        self.tick_formatter2 = tick_formatter2
+        self.update_transform(transform)
+
+    def get_grid_info(self, x1, y1, x2, y2):
+        """
+        lon_values, lat_values : list of grid values. if integer is given,
+                           rough number of grids in each direction.
+        """
+
+        extremes = self.extreme_finder(self.inv_transform_xy, x1, y1, x2, y2)
+
+        # min & max rage of lat (or lon) for each grid line will be drawn.
+        # i.e., gridline of lon=0 will be drawn from lat_min to lat_max.
+
+        lon_min, lon_max, lat_min, lat_max = extremes
+        lon_levs, lon_n, lon_factor = self.grid_locator1(lon_min, lon_max)
+        lat_levs, lat_n, lat_factor = self.grid_locator2(lat_min, lat_max)
+
+        lon_values = lon_levs[:lon_n] / _deprecate_factor_none(lon_factor)
+        lat_values = lat_levs[:lat_n] / _deprecate_factor_none(lat_factor)
+
+        lon_lines, lat_lines = self._get_raw_grid_lines(lon_values,
+                                                        lat_values,
+                                                        lon_min, lon_max,
+                                                        lat_min, lat_max)
+
+        ddx = (x2-x1)*1.e-10
+        ddy = (y2-y1)*1.e-10
+        bb = Bbox.from_extents(x1-ddx, y1-ddy, x2+ddx, y2+ddy)
+
+        grid_info = {
+            "extremes": extremes,
+            "lon_lines": lon_lines,
+            "lat_lines": lat_lines,
+            "lon": self._clip_grid_lines_and_find_ticks(
+                lon_lines, lon_values, lon_levs, bb),
+            "lat": self._clip_grid_lines_and_find_ticks(
+                lat_lines, lat_values, lat_levs, bb),
+        }
+
+        tck_labels = grid_info["lon"]["tick_labels"] = {}
+        for direction in ["left", "bottom", "right", "top"]:
+            levs = grid_info["lon"]["tick_levels"][direction]
+            tck_labels[direction] = self.tick_formatter1(
+                direction, lon_factor, levs)
+
+        tck_labels = grid_info["lat"]["tick_labels"] = {}
+        for direction in ["left", "bottom", "right", "top"]:
+            levs = grid_info["lat"]["tick_levels"][direction]
+            tck_labels[direction] = self.tick_formatter2(
+                direction, lat_factor, levs)
+
+        return grid_info
+
+    def _get_raw_grid_lines(self,
+                            lon_values, lat_values,
+                            lon_min, lon_max, lat_min, lat_max):
+
+        lons_i = np.linspace(lon_min, lon_max, 100)  # for interpolation
+        lats_i = np.linspace(lat_min, lat_max, 100)
+
+        lon_lines = [self.transform_xy(np.full_like(lats_i, lon), lats_i)
+                     for lon in lon_values]
+        lat_lines = [self.transform_xy(lons_i, np.full_like(lons_i, lat))
+                     for lat in lat_values]
+
+        return lon_lines, lat_lines
+
+    def _clip_grid_lines_and_find_ticks(self, lines, values, levs, bb):
+        gi = {
+            "values": [],
+            "levels": [],
+            "tick_levels": dict(left=[], bottom=[], right=[], top=[]),
+            "tick_locs": dict(left=[], bottom=[], right=[], top=[]),
+            "lines": [],
+        }
+
+        tck_levels = gi["tick_levels"]
+        tck_locs = gi["tick_locs"]
+        for (lx, ly), v, lev in zip(lines, values, levs):
+            xy, tcks = clip_line_to_rect(lx, ly, bb)
+            if not xy:
+                continue
+            gi["levels"].append(v)
+            gi["lines"].append(xy)
+
+            for tck, direction in zip(tcks,
+                                      ["left", "bottom", "right", "top"]):
+                for t in tck:
+                    tck_levels[direction].append(lev)
+                    tck_locs[direction].append(t)
+
+        return gi
+
+    def update_transform(self, aux_trans):
+        if isinstance(aux_trans, Transform):
+            def transform_xy(x, y):
+                ll1 = np.column_stack([x, y])
+                ll2 = aux_trans.transform(ll1)
+                lon, lat = ll2[:, 0], ll2[:, 1]
+                return lon, lat
+
+            def inv_transform_xy(x, y):
+                ll1 = np.column_stack([x, y])
+                ll2 = aux_trans.inverted().transform(ll1)
+                lon, lat = ll2[:, 0], ll2[:, 1]
+                return lon, lat
+
+        else:
+            transform_xy, inv_transform_xy = aux_trans
+
+        self.transform_xy = transform_xy
+        self.inv_transform_xy = inv_transform_xy
+
+    def update(self, **kw):
+        for k in kw:
+            if k in ["extreme_finder",
+                     "grid_locator1",
+                     "grid_locator2",
+                     "tick_formatter1",
+                     "tick_formatter2"]:
+                setattr(self, k, kw[k])
+            else:
+                raise ValueError("Unknown update property '%s'" % k)
+
+
+@cbook.deprecated("3.2")
+class GridFinderBase(GridFinder):
+    def __init__(self,
+                 extreme_finder,
+                 grid_locator1=None,
+                 grid_locator2=None,
+                 tick_formatter1=None,
+                 tick_formatter2=None):
+        super().__init__((None, None), extreme_finder,
+                         grid_locator1, grid_locator2,
+                         tick_formatter1, tick_formatter2)
+
+
+class MaxNLocator(mticker.MaxNLocator):
+    def __init__(self, nbins=10, steps=None,
+                 trim=True,
+                 integer=False,
+                 symmetric=False,
+                 prune=None):
+        # trim argument has no effect. It has been left for API compatibility
+        mticker.MaxNLocator.__init__(self, nbins, steps=steps,
+                                     integer=integer,
+                                     symmetric=symmetric, prune=prune)
+        self.create_dummy_axis()
+        self._factor = 1
+
+    def __call__(self, v1, v2):
+        self.set_bounds(v1 * self._factor, v2 * self._factor)
+        locs = mticker.MaxNLocator.__call__(self)
+        return np.array(locs), len(locs), self._factor
+
+    @cbook.deprecated("3.3")
+    def set_factor(self, f):
+        self._factor = _deprecate_factor_none(f)
+
+
+class FixedLocator:
+    def __init__(self, locs):
+        self._locs = locs
+        self._factor = 1
+
+    def __call__(self, v1, v2):
+        v1, v2 = sorted([v1 * self._factor, v2 * self._factor])
+        locs = np.array([l for l in self._locs if v1 <= l <= v2])
+        return locs, len(locs), self._factor
+
+    @cbook.deprecated("3.3")
+    def set_factor(self, f):
+        self._factor = _deprecate_factor_none(f)
+
+
+# Tick Formatter
+
+class FormatterPrettyPrint:
+    def __init__(self, useMathText=True):
+        self._fmt = mticker.ScalarFormatter(
+            useMathText=useMathText, useOffset=False)
+        self._fmt.create_dummy_axis()
+
+    def __call__(self, direction, factor, values):
+        return self._fmt.format_ticks(values)
+
+
+class DictFormatter:
+    def __init__(self, format_dict, formatter=None):
+        """
+        format_dict : dictionary for format strings to be used.
+        formatter : fall-back formatter
+        """
+        super().__init__()
+        self._format_dict = format_dict
+        self._fallback_formatter = formatter
+
+    def __call__(self, direction, factor, values):
+        """
+        factor is ignored if value is found in the dictionary
+        """
+        if self._fallback_formatter:
+            fallback_strings = self._fallback_formatter(
+                direction, factor, values)
+        else:
+            fallback_strings = [""] * len(values)
+        return [self._format_dict.get(k, v)
+                for k, v in zip(values, fallback_strings)]

venv/Lib/site-packages/mpl_toolkits/axisartist/grid_helper_curvelinear.py

@@ -0,0 +1,398 @@
+"""
+An experimental support for curvilinear grid.
+"""
+from itertools import chain
+
+import numpy as np
+
+from matplotlib.path import Path
+from matplotlib.transforms import Affine2D, IdentityTransform
+from .axislines import AxisArtistHelper, GridHelperBase
+from .axis_artist import AxisArtist
+from .grid_finder import GridFinder, _deprecate_factor_none
+
+
+class FixedAxisArtistHelper(AxisArtistHelper.Fixed):
+    """
+    Helper class for a fixed axis.
+    """
+
+    def __init__(self, grid_helper, side, nth_coord_ticks=None):
+        """
+        nth_coord = along which coordinate value varies.
+         nth_coord = 0 ->  x axis, nth_coord = 1 -> y axis
+        """
+
+        super().__init__(loc=side)
+
+        self.grid_helper = grid_helper
+        if nth_coord_ticks is None:
+            nth_coord_ticks = self.nth_coord
+        self.nth_coord_ticks = nth_coord_ticks
+
+        self.side = side
+        self._limits_inverted = False
+
+    def update_lim(self, axes):
+        self.grid_helper.update_lim(axes)
+
+        if self.nth_coord == 0:
+            xy1, xy2 = axes.get_ylim()
+        else:
+            xy1, xy2 = axes.get_xlim()
+
+        if xy1 > xy2:
+            self._limits_inverted = True
+        else:
+            self._limits_inverted = False
+
+    def change_tick_coord(self, coord_number=None):
+        if coord_number is None:
+            self.nth_coord_ticks = 1 - self.nth_coord_ticks
+        elif coord_number in [0, 1]:
+            self.nth_coord_ticks = coord_number
+        else:
+            raise Exception("wrong coord number")
+
+    def get_tick_transform(self, axes):
+        return axes.transData
+
+    def get_tick_iterators(self, axes):
+        """tick_loc, tick_angle, tick_label"""
+
+        g = self.grid_helper
+
+        if self._limits_inverted:
+            side = {"left": "right", "right": "left",
+                    "top": "bottom", "bottom": "top"}[self.side]
+        else:
+            side = self.side
+
+        ti1 = g.get_tick_iterator(self.nth_coord_ticks, side)
+        ti2 = g.get_tick_iterator(1-self.nth_coord_ticks, side, minor=True)
+
+        return chain(ti1, ti2), iter([])
+
+
+class FloatingAxisArtistHelper(AxisArtistHelper.Floating):
+
+    def __init__(self, grid_helper, nth_coord, value, axis_direction=None):
+        """
+        nth_coord = along which coordinate value varies.
+         nth_coord = 0 ->  x axis, nth_coord = 1 -> y axis
+        """
+
+        super().__init__(nth_coord, value)
+        self.value = value
+        self.grid_helper = grid_helper
+        self._extremes = -np.inf, np.inf
+
+        self._get_line_path = None  # a method that returns a Path.
+        self._line_num_points = 100  # number of points to create a line
+
+    def set_extremes(self, e1, e2):
+        if e1 is None:
+            e1 = -np.inf
+        if e2 is None:
+            e2 = np.inf
+        self._extremes = e1, e2
+
+    def update_lim(self, axes):
+        self.grid_helper.update_lim(axes)
+
+        x1, x2 = axes.get_xlim()
+        y1, y2 = axes.get_ylim()
+        grid_finder = self.grid_helper.grid_finder
+        extremes = grid_finder.extreme_finder(grid_finder.inv_transform_xy,
+                                              x1, y1, x2, y2)
+
+        lon_min, lon_max, lat_min, lat_max = extremes
+        e_min, e_max = self._extremes  # ranges of other coordinates
+        if self.nth_coord == 0:
+            lat_min = max(e_min, lat_min)
+            lat_max = min(e_max, lat_max)
+        elif self.nth_coord == 1:
+            lon_min = max(e_min, lon_min)
+            lon_max = min(e_max, lon_max)
+
+        lon_levs, lon_n, lon_factor = \
+            grid_finder.grid_locator1(lon_min, lon_max)
+        lat_levs, lat_n, lat_factor = \
+            grid_finder.grid_locator2(lat_min, lat_max)
+
+        if self.nth_coord == 0:
+            xx0 = np.full(self._line_num_points, self.value, type(self.value))
+            yy0 = np.linspace(lat_min, lat_max, self._line_num_points)
+            xx, yy = grid_finder.transform_xy(xx0, yy0)
+        elif self.nth_coord == 1:
+            xx0 = np.linspace(lon_min, lon_max, self._line_num_points)
+            yy0 = np.full(self._line_num_points, self.value, type(self.value))
+            xx, yy = grid_finder.transform_xy(xx0, yy0)
+
+        self.grid_info = {
+            "extremes": (lon_min, lon_max, lat_min, lat_max),
+            "lon_info": (lon_levs, lon_n, _deprecate_factor_none(lon_factor)),
+            "lat_info": (lat_levs, lat_n, _deprecate_factor_none(lat_factor)),
+            "lon_labels": grid_finder.tick_formatter1(
+                "bottom", _deprecate_factor_none(lon_factor), lon_levs),
+            "lat_labels": grid_finder.tick_formatter2(
+                "bottom", _deprecate_factor_none(lat_factor), lat_levs),
+            "line_xy": (xx, yy),
+        }
+
+    def get_axislabel_transform(self, axes):
+        return Affine2D()  # axes.transData
+
+    def get_axislabel_pos_angle(self, axes):
+
+        extremes = self.grid_info["extremes"]
+
+        if self.nth_coord == 0:
+            xx0 = self.value
+            yy0 = (extremes[2] + extremes[3]) / 2
+            dxx = 0
+            dyy = abs(extremes[2] - extremes[3]) / 1000
+        elif self.nth_coord == 1:
+            xx0 = (extremes[0] + extremes[1]) / 2
+            yy0 = self.value
+            dxx = abs(extremes[0] - extremes[1]) / 1000
+            dyy = 0
+
+        grid_finder = self.grid_helper.grid_finder
+        (xx1,), (yy1,) = grid_finder.transform_xy([xx0], [yy0])
+
+        data_to_axes = axes.transData - axes.transAxes
+        p = data_to_axes.transform([xx1, yy1])
+
+        if 0 <= p[0] <= 1 and 0 <= p[1] <= 1:
+            xx1c, yy1c = axes.transData.transform([xx1, yy1])
+            (xx2,), (yy2,) = grid_finder.transform_xy([xx0 + dxx], [yy0 + dyy])
+            xx2c, yy2c = axes.transData.transform([xx2, yy2])
+            return (xx1c, yy1c), np.rad2deg(np.arctan2(yy2c-yy1c, xx2c-xx1c))
+        else:
+            return None, None
+
+    def get_tick_transform(self, axes):
+        return IdentityTransform()  # axes.transData
+
+    def get_tick_iterators(self, axes):
+        """tick_loc, tick_angle, tick_label, (optionally) tick_label"""
+
+        grid_finder = self.grid_helper.grid_finder
+
+        lat_levs, lat_n, lat_factor = self.grid_info["lat_info"]
+        lat_levs = np.asarray(lat_levs)
+        yy0 = lat_levs / _deprecate_factor_none(lat_factor)
+        dy = 0.01 / _deprecate_factor_none(lat_factor)
+
+        lon_levs, lon_n, lon_factor = self.grid_info["lon_info"]
+        lon_levs = np.asarray(lon_levs)
+        xx0 = lon_levs / _deprecate_factor_none(lon_factor)
+        dx = 0.01 / _deprecate_factor_none(lon_factor)
+
+        if None in self._extremes:
+            e0, e1 = self._extremes
+        else:
+            e0, e1 = sorted(self._extremes)
+        if e0 is None:
+            e0 = -np.inf
+        if e1 is None:
+            e1 = np.inf
+
+        if self.nth_coord == 0:
+            mask = (e0 <= yy0) & (yy0 <= e1)
+            #xx0, yy0 = xx0[mask], yy0[mask]
+            yy0 = yy0[mask]
+        elif self.nth_coord == 1:
+            mask = (e0 <= xx0) & (xx0 <= e1)
+            #xx0, yy0 = xx0[mask], yy0[mask]
+            xx0 = xx0[mask]
+
+        def transform_xy(x, y):
+            x1, y1 = grid_finder.transform_xy(x, y)
+            x2y2 = axes.transData.transform(np.array([x1, y1]).transpose())
+            x2, y2 = x2y2.transpose()
+            return x2, y2
+
+        # find angles
+        if self.nth_coord == 0:
+            xx0 = np.full_like(yy0, self.value)
+
+            xx1, yy1 = transform_xy(xx0, yy0)
+
+            xx00 = xx0.copy()
+            xx00[xx0 + dx > e1] -= dx
+            xx1a, yy1a = transform_xy(xx00, yy0)
+            xx1b, yy1b = transform_xy(xx00+dx, yy0)
+
+            xx2a, yy2a = transform_xy(xx0, yy0)
+            xx2b, yy2b = transform_xy(xx0, yy0+dy)
+
+            labels = self.grid_info["lat_labels"]
+            labels = [l for l, m in zip(labels, mask) if m]
+
+        elif self.nth_coord == 1:
+            yy0 = np.full_like(xx0, self.value)
+
+            xx1, yy1 = transform_xy(xx0, yy0)
+
+            xx1a, yy1a = transform_xy(xx0, yy0)
+            xx1b, yy1b = transform_xy(xx0, yy0+dy)
+
+            xx00 = xx0.copy()
+            xx00[xx0 + dx > e1] -= dx
+            xx2a, yy2a = transform_xy(xx00, yy0)
+            xx2b, yy2b = transform_xy(xx00+dx, yy0)
+
+            labels = self.grid_info["lon_labels"]
+            labels = [l for l, m in zip(labels, mask) if m]
+
+        def f1():
+            dd = np.arctan2(yy1b-yy1a, xx1b-xx1a)  # angle normal
+            dd2 = np.arctan2(yy2b-yy2a, xx2b-xx2a)  # angle tangent
+            mm = (yy1b == yy1a) & (xx1b == xx1a)  # mask where dd not defined
+            dd[mm] = dd2[mm] + np.pi / 2
+
+            tick_to_axes = self.get_tick_transform(axes) - axes.transAxes
+            for x, y, d, d2, lab in zip(xx1, yy1, dd, dd2, labels):
+                c2 = tick_to_axes.transform((x, y))
+                delta = 0.00001
+                if 0-delta <= c2[0] <= 1+delta and 0-delta <= c2[1] <= 1+delta:
+                    d1, d2 = np.rad2deg([d, d2])
+                    yield [x, y], d1, d2, lab
+
+        return f1(), iter([])
+
+    def get_line_transform(self, axes):
+        return axes.transData
+
+    def get_line(self, axes):
+        self.update_lim(axes)
+        x, y = self.grid_info["line_xy"]
+
+        if self._get_line_path is None:
+            return Path(np.column_stack([x, y]))
+        else:
+            return self._get_line_path(axes, x, y)
+
+
+class GridHelperCurveLinear(GridHelperBase):
+
+    def __init__(self, aux_trans,
+                 extreme_finder=None,
+                 grid_locator1=None,
+                 grid_locator2=None,
+                 tick_formatter1=None,
+                 tick_formatter2=None):
+        """
+        aux_trans : a transform from the source (curved) coordinate to
+        target (rectilinear) coordinate. An instance of MPL's Transform
+        (inverse transform should be defined) or a tuple of two callable
+        objects which defines the transform and its inverse. The callables
+        need take two arguments of array of source coordinates and
+        should return two target coordinates.
+
+        e.g., ``x2, y2 = trans(x1, y1)``
+        """
+        super().__init__()
+        self.grid_info = None
+        self._old_values = None
+        self._aux_trans = aux_trans
+        self.grid_finder = GridFinder(aux_trans,
+                                      extreme_finder,
+                                      grid_locator1,
+                                      grid_locator2,
+                                      tick_formatter1,
+                                      tick_formatter2)
+
+    def update_grid_finder(self, aux_trans=None, **kw):
+        if aux_trans is not None:
+            self.grid_finder.update_transform(aux_trans)
+        self.grid_finder.update(**kw)
+        self.invalidate()
+
+    def _update(self, x1, x2, y1, y2):
+        """bbox in 0-based image coordinates"""
+        # update wcsgrid
+        if self.valid() and self._old_values == (x1, x2, y1, y2):
+            return
+        self._update_grid(x1, y1, x2, y2)
+        self._old_values = (x1, x2, y1, y2)
+        self._force_update = False
+
+    def new_fixed_axis(self, loc,
+                       nth_coord=None,
+                       axis_direction=None,
+                       offset=None,
+                       axes=None):
+        if axes is None:
+            axes = self.axes
+        if axis_direction is None:
+            axis_direction = loc
+        _helper = FixedAxisArtistHelper(self, loc, nth_coord_ticks=nth_coord)
+        axisline = AxisArtist(axes, _helper, axis_direction=axis_direction)
+        # Why is clip not set on axisline, unlike in new_floating_axis or in
+        # the floating_axig.GridHelperCurveLinear subclass?
+        return axisline
+
+    def new_floating_axis(self, nth_coord,
+                          value,
+                          axes=None,
+                          axis_direction="bottom"
+                          ):
+
+        if axes is None:
+            axes = self.axes
+
+        _helper = FloatingAxisArtistHelper(
+            self, nth_coord, value, axis_direction)
+
+        axisline = AxisArtist(axes, _helper)
+
+        # _helper = FloatingAxisArtistHelper(self, nth_coord,
+        #                                    value,
+        #                                    label_direction=label_direction,
+        #                                    )
+
+        # axisline = AxisArtistFloating(axes, _helper,
+        #                               axis_direction=axis_direction)
+        axisline.line.set_clip_on(True)
+        axisline.line.set_clip_box(axisline.axes.bbox)
+        # axisline.major_ticklabels.set_visible(True)
+        # axisline.minor_ticklabels.set_visible(False)
+
+        return axisline
+
+    def _update_grid(self, x1, y1, x2, y2):
+        self.grid_info = self.grid_finder.get_grid_info(x1, y1, x2, y2)
+
+    def get_gridlines(self, which="major", axis="both"):
+        grid_lines = []
+        if axis in ["both", "x"]:
+            for gl in self.grid_info["lon"]["lines"]:
+                grid_lines.extend(gl)
+        if axis in ["both", "y"]:
+            for gl in self.grid_info["lat"]["lines"]:
+                grid_lines.extend(gl)
+        return grid_lines
+
+    def get_tick_iterator(self, nth_coord, axis_side, minor=False):
+
+        # axisnr = dict(left=0, bottom=1, right=2, top=3)[axis_side]
+        angle_tangent = dict(left=90, right=90, bottom=0, top=0)[axis_side]
+        # angle = [0, 90, 180, 270][axisnr]
+        lon_or_lat = ["lon", "lat"][nth_coord]
+        if not minor:  # major ticks
+            for (xy, a), l in zip(
+                    self.grid_info[lon_or_lat]["tick_locs"][axis_side],
+                    self.grid_info[lon_or_lat]["tick_labels"][axis_side]):
+                angle_normal = a
+                yield xy, angle_normal, angle_tangent, l
+        else:
+            for (xy, a), l in zip(
+                    self.grid_info[lon_or_lat]["tick_locs"][axis_side],
+                    self.grid_info[lon_or_lat]["tick_labels"][axis_side]):
+                angle_normal = a
+                yield xy, angle_normal, angle_tangent, ""
+            # for xy, a, l in self.grid_info[lon_or_lat]["ticks"][axis_side]:
+            #     yield xy, a, ""

venv/Lib/site-packages/mpl_toolkits/axisartist/parasite_axes.py

@@ -0,0 +1,10 @@
+from mpl_toolkits.axes_grid1.parasite_axes import (
+    host_axes_class_factory, parasite_axes_class_factory,
+    parasite_axes_auxtrans_class_factory, subplot_class_factory)
+from .axislines import Axes
+
+
+ParasiteAxes = parasite_axes_class_factory(Axes)
+ParasiteAxesAuxTrans = parasite_axes_auxtrans_class_factory(ParasiteAxes)
+HostAxes = host_axes_class_factory(Axes)
+SubplotHost = subplot_class_factory(HostAxes)