From b6ffb54b676803f21496e6a1ff1a6efd5284543d Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Tue, 1 Sep 2026 14:41:38 +0000
Subject: [PATCH 1/6] Convert polar plots to plotly polar subplots

---
 plotly/matplotlylib/renderer.py            | 89 ++++++++++++++++++++++
 plotly/matplotlylib/tests/test_renderer.py | 22 ++++++
 2 files changed, 111 insertions(+)

diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index be10cd9af9..7fbc74409e 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -10,6 +10,7 @@
 import warnings
 
 import matplotlib.patches as mpatches
+import numpy as np
 import plotly.graph_objs as go
 from plotly.matplotlylib.mplexporter import Renderer
 from plotly.matplotlylib import mpltools
@@ -86,6 +87,9 @@ def __init__(self):
         self.current_bars = []
         self.axis_ct = 0
         self.x_is_mpl_date = False
+        self.current_is_polar = False
+        self.polar_ct = 0
+        self.current_polar_subplot = None
         self.mpl_x_bounds = (0, 1)
         self.mpl_y_bounds = (0, 1)
         self.msg = "Initialized PlotlyRenderer\n"
@@ -102,6 +106,35 @@ def _convert_x_dates(self, x):
             x = mpltools.mpl_dates_to_datestrings(x, formatter)
         return x
 
+    def _open_polar_axes(self, ax):
+        """Create a plotly polar layout object for a matplotlib polar axes.
+
+        matplotlib polar data coordinates are (theta, r) with theta in
+        radians measured from the positive x-axis (east). Plotly polar
+        angles are in degrees measured from 12 o'clock, so the angular
+        axis rotation and direction are set to map the two systems onto
+        each other.
+        """
+        self.polar_ct += 1
+        self.current_polar_subplot = (
+            "polar{0}".format(self.polar_ct) if self.polar_ct > 1 else "polar"
+        )
+        theta_offset = ax.get_theta_offset()
+        theta_direction = ax.get_theta_direction()
+        self.plotly_fig["layout"][self.current_polar_subplot] = go.layout.Polar(
+            angularaxis=dict(
+                rotation=90 - float(np.degrees(theta_offset)),
+                direction=("clockwise" if theta_direction >= 0 else "counterclockwise"),
+                tickvals=[float(t) for t in np.degrees(ax.xaxis.get_majorticklocs())],
+                ticktext=[t.get_text() for t in ax.xaxis.get_majorticklabels()],
+            ),
+            radialaxis=dict(
+                range=[float(v) for v in ax.get_ylim()],
+                tickvals=[float(t) for t in ax.yaxis.get_majorticklocs()],
+                ticktext=[t.get_text() for t in ax.yaxis.get_majorticklabels()],
+            ),
+        )
+
     def open_figure(self, fig, props):
         """Creates a new figure by beginning to fill out layout dict.
 
@@ -195,6 +228,11 @@ def open_axes(self, ax, props):
             if c.__class__.__name__ == "BarContainer"
         ]
         self.current_bars = []
+        self.current_is_polar = getattr(ax, "name", None) == "polar"
+        if self.current_is_polar:
+            self.msg += "  Opening polar axes\n"
+            self._open_polar_axes(ax)
+            return
         self.axis_ct += 1
         if props.get("patch_visible", True):
             self.plotly_fig["layout"].plot_bgcolor = _export_color(props["axesbg"])
@@ -301,6 +339,7 @@ def close_axes(self, ax):
         self.draw_bars(self.current_bars)
         self.msg += "  Closing axes\n"
         self.x_is_mpl_date = False
+        self.current_is_polar = False
 
     def open_legend(self, legend, props):
         """Enable Plotly's native legend when matplotlib legend is detected.
@@ -535,6 +574,41 @@ def draw_marked_line(self, **props):
                 showlegend = False
             else:
                 showlegend = None
+            if self.current_is_polar:
+                self.plotly_fig.add_trace(
+                    go.Scatterpolar(
+                        mode=mode,
+                        name=label,
+                        theta=np.degrees([xy_pair[0] for xy_pair in props["data"]]),
+                        r=[xy_pair[1] for xy_pair in props["data"]],
+                        subplot=self.current_polar_subplot,
+                        line=(
+                            go.scatterpolar.Line(
+                                color=line.color,
+                                width=line.width,
+                                dash=line.dash,
+                            )
+                            if props["linestyle"]
+                            else None
+                        ),
+                        marker=(
+                            go.scatterpolar.Marker(
+                                opacity=marker.opacity,
+                                color=marker.color,
+                                symbol=marker.symbol,
+                                size=marker.size,
+                                line=dict(
+                                    color=marker.line.color,
+                                    width=marker.line.width,
+                                ),
+                            )
+                            if props["markerstyle"]
+                            else None
+                        ),
+                    )
+                )
+                self.msg += "    Heck yeah, I drew that line on polar axes\n"
+                return
             marked_line = go.Scatter(
                 mode=mode,
                 name=label,
@@ -738,6 +812,21 @@ def _draw_filled_path_collection(self, props):
             facecolor = _per_path(facecolors, i, "rgba(0,0,0,0)")
             edgecolor = _per_path(edgecolors, i, "rgba(0,0,0,0)")
             linewidth = _per_path(linewidths, i, 0)
+            if self.current_is_polar:
+                self.plotly_fig.add_trace(
+                    go.Scatterpolar(
+                        theta=np.degrees([v[0] for v in verts]),
+                        r=[v[1] for v in verts],
+                        mode="lines",
+                        line=go.scatterpolar.Line(
+                            color=_export_color(edgecolor), width=linewidth
+                        ),
+                        fill="toself",
+                        fillcolor=_export_color(facecolor),
+                        subplot=self.current_polar_subplot,
+                    )
+                )
+                continue
             self.plotly_fig.add_trace(
                 go.Scatter(
                     x=self._convert_x_dates([v[0] for v in verts]),
diff --git a/plotly/matplotlylib/tests/test_renderer.py b/plotly/matplotlylib/tests/test_renderer.py
index a355db7dc4..2a21ea8661 100644
--- a/plotly/matplotlylib/tests/test_renderer.py
+++ b/plotly/matplotlylib/tests/test_renderer.py
@@ -852,6 +852,28 @@ def test_uneven_custom_date_xtickvals_are_converted():
     )
 
 
+def test_polar_plot_converts():
+    """Polar plots convert to scatterpolar traces on a plotly polar layout,
+    with theta converted from radians to degrees."""
+    t = np.linspace(0, 2 * np.pi, 200)
+    fig, ax = plt.subplots(subplot_kw={"projection": "polar"})
+    ax.plot(t, 1 + 0.5 * np.sin(3 * t))
+
+    plotly_fig = tls.mpl_to_plotly(fig)
+
+    trace = plotly_fig.data[0]
+    assert trace.type == "scatterpolar"
+    assert trace.subplot == "polar"
+    assert np.allclose(trace.theta[0], 0)
+    assert np.allclose(trace.r[0], 1)
+    assert np.allclose(trace.theta[-1], 360)
+    polar = plotly_fig.layout.polar
+    assert polar.angularaxis.direction == "clockwise"
+    assert polar.angularaxis.rotation == 90
+    assert polar.angularaxis.ticktext[0] == "0°"
+    assert polar.radialaxis.range == tuple(float(v) for v in ax.get_ylim())
+
+
 def test_custom_date_xtickvals_given_as_numbers_are_converted():
     """Custom date ticks given as matplotlib date numbers must be converted
     to date strings."""

From 9f1267bd713458ac703063a211f1d2db56859433 Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Tue, 1 Sep 2026 14:56:55 +0000
Subject: [PATCH 2/6] Fix polar angular axis direction and rotation

---
 plotly/matplotlylib/renderer.py            | 15 +++++++++------
 plotly/matplotlylib/tests/test_renderer.py |  4 ++--
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index 7fbc74409e..46ea1dd703 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -110,10 +110,11 @@ def _open_polar_axes(self, ax):
         """Create a plotly polar layout object for a matplotlib polar axes.
 
         matplotlib polar data coordinates are (theta, r) with theta in
-        radians measured from the positive x-axis (east). Plotly polar
-        angles are in degrees measured from 12 o'clock, so the angular
-        axis rotation and direction are set to map the two systems onto
-        each other.
+        radians measured from the positive x-axis (east). Plotly angular
+        values are in degrees, with the rotation property setting the
+        position of angular value 0 and direction setting the direction
+        of positive angles, so both are taken from the matplotlib axes
+        to map the two coordinate systems onto each other.
         """
         self.polar_ct += 1
         self.current_polar_subplot = (
@@ -123,8 +124,10 @@ def _open_polar_axes(self, ax):
         theta_direction = ax.get_theta_direction()
         self.plotly_fig["layout"][self.current_polar_subplot] = go.layout.Polar(
             angularaxis=dict(
-                rotation=90 - float(np.degrees(theta_offset)),
-                direction=("clockwise" if theta_direction >= 0 else "counterclockwise"),
+                rotation=float(np.degrees(theta_offset)),
+                direction=(
+                    "counterclockwise" if theta_direction >= 0 else "clockwise"
+                ),
                 tickvals=[float(t) for t in np.degrees(ax.xaxis.get_majorticklocs())],
                 ticktext=[t.get_text() for t in ax.xaxis.get_majorticklabels()],
             ),
diff --git a/plotly/matplotlylib/tests/test_renderer.py b/plotly/matplotlylib/tests/test_renderer.py
index 2a21ea8661..5514e22138 100644
--- a/plotly/matplotlylib/tests/test_renderer.py
+++ b/plotly/matplotlylib/tests/test_renderer.py
@@ -868,8 +868,8 @@ def test_polar_plot_converts():
     assert np.allclose(trace.r[0], 1)
     assert np.allclose(trace.theta[-1], 360)
     polar = plotly_fig.layout.polar
-    assert polar.angularaxis.direction == "clockwise"
-    assert polar.angularaxis.rotation == 90
+    assert polar.angularaxis.direction == "counterclockwise"
+    assert polar.angularaxis.rotation == 0
     assert polar.angularaxis.ticktext[0] == "0°"
     assert polar.radialaxis.range == tuple(float(v) for v in ax.get_ylim())
 

From 018bd99ff342d09b768f976dafd6159304bd3e8f Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Tue, 1 Sep 2026 16:32:50 +0000
Subject: [PATCH 3/6] Take polar background, grid, and frame colors from
 matplotlib

---
 plotly/matplotlylib/renderer.py            | 38 ++++++++++++++++++----
 plotly/matplotlylib/tests/test_renderer.py |  6 ++++
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index 46ea1dd703..49c45e860a 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -106,7 +106,7 @@ def _convert_x_dates(self, x):
             x = mpltools.mpl_dates_to_datestrings(x, formatter)
         return x
 
-    def _open_polar_axes(self, ax):
+    def _open_polar_axes(self, ax, props):
         """Create a plotly polar layout object for a matplotlib polar axes.
 
         matplotlib polar data coordinates are (theta, r) with theta in
@@ -114,7 +114,9 @@ def _open_polar_axes(self, ax):
         values are in degrees, with the rotation property setting the
         position of angular value 0 and direction setting the direction
         of positive angles, so both are taken from the matplotlib axes
-        to map the two coordinate systems onto each other.
+        to map the two coordinate systems onto each other. Background,
+        grid, and frame colors are taken from the matplotlib axes like
+        they are for cartesian axes.
         """
         self.polar_ct += 1
         self.current_polar_subplot = (
@@ -122,19 +124,43 @@ def _open_polar_axes(self, ax):
         )
         theta_offset = ax.get_theta_offset()
         theta_direction = ax.get_theta_direction()
+        angular_gridlines = ax.xaxis.get_gridlines()
+        radial_gridlines = ax.yaxis.get_gridlines()
+        angular_grid = (
+            (angular_gridlines[0].get_color(), angular_gridlines[0].get_visible())
+            if len(angular_gridlines)
+            else ("#b0b0b0", True)
+        )
+        radial_grid = (
+            (radial_gridlines[0].get_color(), radial_gridlines[0].get_visible())
+            if len(radial_gridlines)
+            else ("#b0b0b0", True)
+        )
+        frame = ax.spines.get("polar")
         self.plotly_fig["layout"][self.current_polar_subplot] = go.layout.Polar(
+            bgcolor=_export_color(props["axesbg"]),
             angularaxis=dict(
                 rotation=float(np.degrees(theta_offset)),
-                direction=(
-                    "counterclockwise" if theta_direction >= 0 else "clockwise"
-                ),
+                direction=("counterclockwise" if theta_direction >= 0 else "clockwise"),
                 tickvals=[float(t) for t in np.degrees(ax.xaxis.get_majorticklocs())],
                 ticktext=[t.get_text() for t in ax.xaxis.get_majorticklabels()],
+                showgrid=angular_grid[1],
+                gridcolor=_export_color(angular_grid[0]),
+                showline=frame.get_visible() if frame is not None else True,
+                linecolor=(
+                    _export_color(frame.get_edgecolor())
+                    if frame is not None
+                    else "black"
+                ),
+                linewidth=frame.get_linewidth() if frame is not None else 1,
             ),
             radialaxis=dict(
                 range=[float(v) for v in ax.get_ylim()],
                 tickvals=[float(t) for t in ax.yaxis.get_majorticklocs()],
                 ticktext=[t.get_text() for t in ax.yaxis.get_majorticklabels()],
+                showgrid=radial_grid[1],
+                gridcolor=_export_color(radial_grid[0]),
+                showline=False,
             ),
         )
 
@@ -234,7 +260,7 @@ def open_axes(self, ax, props):
         self.current_is_polar = getattr(ax, "name", None) == "polar"
         if self.current_is_polar:
             self.msg += "  Opening polar axes\n"
-            self._open_polar_axes(ax)
+            self._open_polar_axes(ax, props)
             return
         self.axis_ct += 1
         if props.get("patch_visible", True):
diff --git a/plotly/matplotlylib/tests/test_renderer.py b/plotly/matplotlylib/tests/test_renderer.py
index 5514e22138..0354447c63 100644
--- a/plotly/matplotlylib/tests/test_renderer.py
+++ b/plotly/matplotlylib/tests/test_renderer.py
@@ -872,6 +872,12 @@ def test_polar_plot_converts():
     assert polar.angularaxis.rotation == 0
     assert polar.angularaxis.ticktext[0] == "0°"
     assert polar.radialaxis.range == tuple(float(v) for v in ax.get_ylim())
+    assert polar.bgcolor == "#FFFFFF"
+    assert polar.angularaxis.gridcolor == "#b0b0b0"
+    assert polar.radialaxis.gridcolor == "#b0b0b0"
+    assert polar.angularaxis.linecolor == "#000000"
+    assert polar.angularaxis.linewidth == 0.8
+    assert polar.radialaxis.showline is False
 
 
 def test_custom_date_xtickvals_given_as_numbers_are_converted():

From fc628e1a21e0e7f63d17affaa6eb9db1166e232f Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Wed, 23 Sep 2026 02:18:14 +0000
Subject: [PATCH 4/6] Export polar frame properties in mplexporter

---
 plotly/matplotlylib/mplexporter/utils.py | 11 +++++++++++
 plotly/matplotlylib/renderer.py          | 12 ++++--------
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/plotly/matplotlylib/mplexporter/utils.py b/plotly/matplotlylib/mplexporter/utils.py
index 84bf950ad8..fc84666f96 100644
--- a/plotly/matplotlylib/mplexporter/utils.py
+++ b/plotly/matplotlylib/mplexporter/utils.py
@@ -308,6 +308,17 @@ def get_axes_properties(ax):
         "axes": [get_axis_properties(ax.xaxis), get_axis_properties(ax.yaxis)],
     }
 
+    if getattr(ax, "name", None) == "polar":
+        frame = ax.spines.get("polar")
+        if frame is not None:
+            props["polar_frame"] = {
+                "color": export_color(frame.get_edgecolor()),
+                "linewidth": frame.get_linewidth(),
+                "visible": frame.get_visible(),
+            }
+        else:
+            props["polar_frame"] = None
+
     for axname in ["x", "y"]:
         axis = getattr(ax, axname + "axis")
         domain = getattr(ax, "get_{0}lim".format(axname))()
diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index 49c45e860a..c2b096943e 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -136,7 +136,7 @@ def _open_polar_axes(self, ax, props):
             if len(radial_gridlines)
             else ("#b0b0b0", True)
         )
-        frame = ax.spines.get("polar")
+        frame = props.get("polar_frame")
         self.plotly_fig["layout"][self.current_polar_subplot] = go.layout.Polar(
             bgcolor=_export_color(props["axesbg"]),
             angularaxis=dict(
@@ -146,13 +146,9 @@ def _open_polar_axes(self, ax, props):
                 ticktext=[t.get_text() for t in ax.xaxis.get_majorticklabels()],
                 showgrid=angular_grid[1],
                 gridcolor=_export_color(angular_grid[0]),
-                showline=frame.get_visible() if frame is not None else True,
-                linecolor=(
-                    _export_color(frame.get_edgecolor())
-                    if frame is not None
-                    else "black"
-                ),
-                linewidth=frame.get_linewidth() if frame is not None else 1,
+                showline=frame["visible"] if frame else True,
+                linecolor=(_export_color(frame["color"]) if frame else "black"),
+                linewidth=frame["linewidth"] if frame else 1,
             ),
             radialaxis=dict(
                 range=[float(v) for v in ax.get_ylim()],

From c98af049c86e00a6976897451d740f24f08e6b3b Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Wed, 23 Sep 2026 13:30:54 +0000
Subject: [PATCH 5/6] Export polar grid colors in mplexporter

---
 plotly/matplotlylib/mplexporter/utils.py   | 13 +++++------
 plotly/matplotlylib/renderer.py            | 23 ++++++--------------
 plotly/matplotlylib/tests/test_renderer.py | 25 ++++++++++++++++++++--
 3 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/plotly/matplotlylib/mplexporter/utils.py b/plotly/matplotlylib/mplexporter/utils.py
index fc84666f96..5746dadfcb 100644
--- a/plotly/matplotlylib/mplexporter/utils.py
+++ b/plotly/matplotlylib/mplexporter/utils.py
@@ -278,13 +278,14 @@ def get_axis_properties(axis):
 
 def get_grid_style(axis):
     gridlines = axis.get_gridlines()
-    if axis.get_tick_params()["gridOn"] and len(gridlines) > 0:
-        color = export_color(gridlines[0].get_color())
-        alpha = gridlines[0].get_alpha()
-        dasharray = get_dasharray(gridlines[0])
-        return dict(gridOn=True, color=color, dasharray=dasharray, alpha=alpha)
-    else:
+    if len(gridlines) == 0:
         return {"gridOn": False}
+    return dict(
+        gridOn=axis.get_tick_params().get("gridOn", False),
+        color=export_color(gridlines[0].get_color()),
+        dasharray=get_dasharray(gridlines[0]),
+        alpha=gridlines[0].get_alpha(),
+    )
 
 
 def get_figure_properties(fig):
diff --git a/plotly/matplotlylib/renderer.py b/plotly/matplotlylib/renderer.py
index c2b096943e..7154d39839 100644
--- a/plotly/matplotlylib/renderer.py
+++ b/plotly/matplotlylib/renderer.py
@@ -124,18 +124,9 @@ def _open_polar_axes(self, ax, props):
         )
         theta_offset = ax.get_theta_offset()
         theta_direction = ax.get_theta_direction()
-        angular_gridlines = ax.xaxis.get_gridlines()
-        radial_gridlines = ax.yaxis.get_gridlines()
-        angular_grid = (
-            (angular_gridlines[0].get_color(), angular_gridlines[0].get_visible())
-            if len(angular_gridlines)
-            else ("#b0b0b0", True)
-        )
-        radial_grid = (
-            (radial_gridlines[0].get_color(), radial_gridlines[0].get_visible())
-            if len(radial_gridlines)
-            else ("#b0b0b0", True)
-        )
+        axes = props.get("axes", [])
+        angular_grid = axes[0].get("grid", {}) if len(axes) > 0 else {}
+        radial_grid = axes[1].get("grid", {}) if len(axes) > 1 else {}
         frame = props.get("polar_frame")
         self.plotly_fig["layout"][self.current_polar_subplot] = go.layout.Polar(
             bgcolor=_export_color(props["axesbg"]),
@@ -144,8 +135,8 @@ def _open_polar_axes(self, ax, props):
                 direction=("counterclockwise" if theta_direction >= 0 else "clockwise"),
                 tickvals=[float(t) for t in np.degrees(ax.xaxis.get_majorticklocs())],
                 ticktext=[t.get_text() for t in ax.xaxis.get_majorticklabels()],
-                showgrid=angular_grid[1],
-                gridcolor=_export_color(angular_grid[0]),
+                showgrid=angular_grid.get("gridOn", True),
+                gridcolor=_export_color(angular_grid.get("color", "#B0B0B0")),
                 showline=frame["visible"] if frame else True,
                 linecolor=(_export_color(frame["color"]) if frame else "black"),
                 linewidth=frame["linewidth"] if frame else 1,
@@ -154,8 +145,8 @@ def _open_polar_axes(self, ax, props):
                 range=[float(v) for v in ax.get_ylim()],
                 tickvals=[float(t) for t in ax.yaxis.get_majorticklocs()],
                 ticktext=[t.get_text() for t in ax.yaxis.get_majorticklabels()],
-                showgrid=radial_grid[1],
-                gridcolor=_export_color(radial_grid[0]),
+                showgrid=radial_grid.get("gridOn", True),
+                gridcolor=_export_color(radial_grid.get("color", "#B0B0B0")),
                 showline=False,
             ),
         )
diff --git a/plotly/matplotlylib/tests/test_renderer.py b/plotly/matplotlylib/tests/test_renderer.py
index 0354447c63..53180d2cc2 100644
--- a/plotly/matplotlylib/tests/test_renderer.py
+++ b/plotly/matplotlylib/tests/test_renderer.py
@@ -873,13 +873,34 @@ def test_polar_plot_converts():
     assert polar.angularaxis.ticktext[0] == "0°"
     assert polar.radialaxis.range == tuple(float(v) for v in ax.get_ylim())
     assert polar.bgcolor == "#FFFFFF"
-    assert polar.angularaxis.gridcolor == "#b0b0b0"
-    assert polar.radialaxis.gridcolor == "#b0b0b0"
+    assert polar.angularaxis.gridcolor == "#B0B0B0"
+    assert polar.radialaxis.gridcolor == "#B0B0B0"
     assert polar.angularaxis.linecolor == "#000000"
     assert polar.angularaxis.linewidth == 0.8
     assert polar.radialaxis.showline is False
 
 
+def test_polar_grid_with_tuple_color():
+    """Polar axes with tuple grid colors convert successfully."""
+    fig, ax = plt.subplots(subplot_kw={"projection": "polar"})
+    ax.grid(color=(0.5, 0.5, 0.5))
+    plotly_fig = tls.mpl_to_plotly(fig)
+
+    assert plotly_fig.layout.polar.angularaxis.gridcolor == "#7F7F7F"
+    assert plotly_fig.layout.polar.radialaxis.gridcolor == "#7F7F7F"
+
+
+def test_cartesian_grid_with_tuple_color():
+    """Cartesian axes with tuple grid colors convert successfully."""
+    fig, ax = plt.subplots()
+    ax.grid(color=(0.5, 0.5, 0.5))
+    ax.plot([0, 1], [0, 1])
+    plotly_fig = tls.mpl_to_plotly(fig)
+
+    assert plotly_fig.layout.xaxis.showgrid is True
+    assert plotly_fig.layout.yaxis.showgrid is True
+
+
 def test_custom_date_xtickvals_given_as_numbers_are_converted():
     """Custom date ticks given as matplotlib date numbers must be converted
     to date strings."""

From 3968989c01cc568929c9fbd03f12419cb89aa236 Mon Sep 17 00:00:00 2001
From: Roberto Moura <roberto@ffmoura.com>
Date: Thu, 8 Oct 2026 15:17:27 +0000
Subject: [PATCH 6/6] Add changelog entry

---
 CHANGELOG.md | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b45532a79b..79df290fc0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## Unreleased
 
+### Added
+- Add support for converting matplotlib polar plots to plotly polar subplots in `mpl_to_plotly`, including theta direction and rotation and background, grid, and frame colors [[#5771](https://github.com/plotly/plotly.py/pull/5771)], with thanks to @robertoffmoura for the contribution!
+
 ### Fixed
 - Fix `mpl_to_plotly` tick marker mirroring, axis positioning, and trace visibility for twinned and overlaid subplots (such as `twinx` and `twiny`) [[#5310](https://github.com/plotly/plotly.py/pull/5310)], with thanks to @robertoffmoura for the contribution!
 - Fix `mpl_to_plotly` losing matplotlib axis line colors by exporting the color of each axis's displayed spine to the plotly x and y axis `linecolor` [[#5311](https://github.com/plotly/plotly.py/pull/5311)], with thanks to @robertoffmoura for the contribution!