matplotlib · ksunden · Nov 15, 2022 · Nov 14, 2022
diff --git a/doc/api/next_api_changes/deprecations/24455-AL.rst b/doc/api/next_api_changes/deprecations/24455-AL.rst
@@ -0,0 +1,3 @@
+``RadioButtons.circles``
+~~~~~~~~~~~~~~~~~~~~~~~~
+... is deprecated.  (RadioButtons now draws itself using `~.Axes.scatter`.)
diff --git a/lib/matplotlib/tests/baseline_images/test_widgets/check_bunch_of_radio_buttons.png b/lib/matplotlib/tests/baseline_images/test_widgets/check_bunch_of_radio_buttons.png
diff --git a/lib/matplotlib/tests/test_widgets.py b/lib/matplotlib/tests/test_widgets.py
@@ -1003,18 +1003,21 @@ def test_check_radio_buttons_image():
     plt.subplots_adjust(left=0.3)
     rax1 = plt.axes([0.05, 0.7, 0.15, 0.15])
     rax2 = plt.axes([0.05, 0.2, 0.15, 0.15])
-    widgets.RadioButtons(rax1, ('Radio 1', 'Radio 2', 'Radio 3'))
+    rb = widgets.RadioButtons(rax1, ('Radio 1', 'Radio 2', 'Radio 3'))
+    with pytest.warns(DeprecationWarning):
+        rb.circles  # Trigger the old-style elliptic radiobuttons.
     widgets.CheckButtons(rax2, ('Check 1', 'Check 2', 'Check 3'),
                          (False, True, True))
 
 
-@image_comparison(['check_bunch_of_radio_buttons.png'],
-                  style='mpl20', remove_text=True)
-def test_check_bunch_of_radio_buttons():
-    rax = plt.axes([0.05, 0.1, 0.15, 0.7])
-    widgets.RadioButtons(rax, ('B1', 'B2', 'B3', 'B4', 'B5', 'B6',
-                               'B7', 'B8', 'B9', 'B10', 'B11', 'B12',
-                               'B13', 'B14', 'B15'))
+@check_figures_equal(extensions=["png"])
+def test_radio_buttons(fig_test, fig_ref):
+    widgets.RadioButtons(fig_test.subplots(), ["tea", "coffee"])
+    ax = fig_ref.add_subplot(xticks=[], yticks=[])
+    ax.scatter([.15, .15], [2/3, 1/3], transform=ax.transAxes,
+               s=(plt.rcParams["font.size"] / 2) ** 2, c=["C0", "none"])
+    ax.text(.25, 2/3, "tea", transform=ax.transAxes, va="center")
+    ax.text(.25, 1/3, "coffee", transform=ax.transAxes, va="center")
 
 
 def test_slider_slidermin_slidermax_invalid():

diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -1404,41 +1404,23 @@ def __init__(self, ax, labels, active=0, activecolor='blue'):
         """
         super().__init__(ax)
         self.activecolor = activecolor
-        self.value_selected = None
+        self.value_selected = labels[active]
 
         ax.set_xticks([])
         ax.set_yticks([])
         ax.set_navigate(False)
-        dy = 1. / (len(labels) + 1)
-        ys = np.linspace(1 - dy, dy, len(labels))
-        cnt = 0
-        axcolor = ax.get_facecolor()
-
-        # scale the radius of the circle with the spacing between each one
-        circle_radius = dy / 2 - 0.01
-        # default to hard-coded value if the radius becomes too large
-        circle_radius = min(circle_radius, 0.05)
-
-        self.labels = []
-        self.circles = []
-        for y, label in zip(ys, labels):
-            t = ax.text(0.25, y, label, transform=ax.transAxes,
-                        horizontalalignment='left',
-                        verticalalignment='center')
 
-            if cnt == active:
-                self.value_selected = label
-                facecolor = activecolor
-            else:
-                facecolor = axcolor
+        ys = np.linspace(1, 0, len(labels) + 2)[1:-1]
+        text_size = mpl.rcParams["font.size"] / 2
 
-            p = Circle(xy=(0.15, y), radius=circle_radius, edgecolor='black',
-                       facecolor=facecolor, transform=ax.transAxes)
-
-            self.labels.append(t)
-            self.circles.append(p)
-            ax.add_patch(p)
-            cnt += 1
+        self.labels = [
+            ax.text(0.25, y, label, transform=ax.transAxes,
+                    horizontalalignment="left", verticalalignment="center")
+            for y, label in zip(ys, labels)]
+        self._buttons = ax.scatter(
+            [.15] * len(ys), ys, transform=ax.transAxes, s=text_size**2,
+            c=[activecolor if i == active else "none" for i in range(len(ys))],
+            edgecolor="black")
 
         self.connect_event('button_press_event', self._clicked)
 
@@ -1448,11 +1430,20 @@ def _clicked(self, event):
         if self.ignore(event) or event.button != 1 or event.inaxes != self.ax:
             return
         pclicked = self.ax.transAxes.inverted().transform((event.x, event.y))
+        _, inds = self._buttons.contains(event)
+        coords = self._buttons.get_offset_transform().transform(
+            self._buttons.get_offsets())
         distances = {}
-        for i, (p, t) in enumerate(zip(self.circles, self.labels)):
-            if (t.get_window_extent().contains(event.x, event.y)
-                    or np.linalg.norm(pclicked - p.center) < p.radius):
-                distances[i] = np.linalg.norm(pclicked - p.center)
+        if hasattr(self, "_circles"):  # Remove once circles is removed.
+            for i, (p, t) in enumerate(zip(self._circles, self.labels)):
+                if (t.get_window_extent().contains(event.x, event.y)
+                        or np.linalg.norm(pclicked - p.center) < p.radius):
+                    distances[i] = np.linalg.norm(pclicked - p.center)
+        else:
+            for i, t in enumerate(self.labels):
+                if (i in inds["ind"]
+                        or t.get_window_extent().contains(event.x, event.y)):
+                    distances[i] = np.linalg.norm(pclicked - coords[i])
         if len(distances) > 0:
             closest = min(distances, key=distances.get)
             self.set_active(closest)
@@ -1465,19 +1456,14 @@ def set_active(self, index):
         """
         if index not in range(len(self.labels)):
             raise ValueError(f'Invalid RadioButton index: {index}')
-
         self.value_selected = self.labels[index].get_text()
-
-        for i, p in enumerate(self.circles):
-            if i == index:
-                color = self.activecolor
-            else:
-                color = self.ax.get_facecolor()
-            p.set_facecolor(color)
-
+        self._buttons.get_facecolor()[:] = colors.to_rgba("none")
+        self._buttons.get_facecolor()[index] = colors.to_rgba(self.activecolor)
+        if hasattr(self, "_circles"):  # Remove once circles is removed.
+            for i, p in enumerate(self._circles):
+                p.set_facecolor(self.activecolor if i == index else "none")
         if self.drawon:
             self.ax.figure.canvas.draw()
-
         if self.eventson:
             self._observers.process('clicked', self.labels[index].get_text())
 
@@ -1493,6 +1479,21 @@ def disconnect(self, cid):
         """Remove the observer with connection id *cid*."""
         self._observers.disconnect(cid)
 
+    @_api.deprecated("3.7")
+    @property
+    def circles(self):
+        if not hasattr(self, "_circles"):
+            radius = min(.5 / (len(self.labels) + 1) - .01, .05)
+            circles = self._circles = [
+                Circle(xy=self._buttons.get_offsets()[i], edgecolor="black",
+                       facecolor=self._buttons.get_facecolor()[i],
+                       radius=radius, transform=self.ax.transAxes)
+                for i in range(len(self.labels))]
+            self._buttons.set_visible(False)
+            for circle in circles:
+                self.ax.add_patch(circle)
+        return self._circles
+
 
 class SubplotTool(Widget):
     """