matplotlib · mromanie · Feb 6, 2019 · timhoffm · Mar 12, 2025 · timhoffm
diff --git a/doc/users/next_whats_new/widget_horizontal.rst b/doc/users/next_whats_new/widget_horizontal.rst
@@ -0,0 +1,23 @@
+RadioButtons widget may now be laid out horizontally
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The `.RadioButtons` widget's primary layout direction may now be specified with
+the *layout_direction* keyword argument:
+
+.. plot::
+    :include-source:
+
+    import matplotlib.pyplot as plt
+    from matplotlib.widgets import RadioButtons
+
+    fig = plt.figure(figsize=(4, 2))
+
+    # Default orientation is vertical:
+    rbv = RadioButtons(fig.add_axes((0.05, 0.6, 0.2, 0.35)),
+                       ('Radio 1', 'Radio 2', 'Radio 3'),
+                       layout_direction='vertical')
+
+    # Alternatively, a horizontal orientation may be used:
+    rbh = RadioButtons(fig.add_axes((0.3, 0.6, 0.6, 0.35)),
+                       ('Radio 1', 'Radio 2', 'Radio 3'),
+                       layout_direction='horizontal')
diff --git a/lib/matplotlib/tests/test_widgets.py b/lib/matplotlib/tests/test_widgets.py
@@ -1097,8 +1097,10 @@ def test_TextBox(ax, toolbar):
     assert text_change_event.call_count == 3
 
 
-def test_RadioButtons(ax):
-    radio = widgets.RadioButtons(ax, ('Radio 1', 'Radio 2', 'Radio 3'))
+@pytest.mark.parametrize('layout_direction', ['vertical', 'horizontal'])
+def test_RadioButtons(ax, layout_direction):
+    radio = widgets.RadioButtons(ax, ('Radio 1', 'Radio 2', 'Radio 3'),
+                                 layout_direction=layout_direction)
     radio.set_active(1)
     assert radio.value_selected == 'Radio 2'
     assert radio.index_selected == 1

diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -1557,7 +1557,8 @@ class RadioButtons(AxesWidget):
     """
 
     def __init__(self, ax, labels, active=0, activecolor=None, *,
-                 useblit=True, label_props=None, radio_props=None):
+                 useblit=True, label_props=None, radio_props=None,
+                 layout_direction='vertical'):
         """
         Add radio buttons to an `~.axes.Axes`.
 
@@ -1593,9 +1594,16 @@ def __init__(self, ax, labels, active=0, activecolor=None, *,
                 button.
 
             .. versionadded:: 3.7
+        layout_direction : {'vertical', 'horizontal'}
+            The orientation of the buttons: 'vertical' places buttons from top
+            to bottom, 'horizontal' places buttons from left to right.
-            to bottom, 'horizontal' places buttons from left to right.
+            to bottom, 'horizontal' places buttons from left to right, distributing
+            the buttons across the whole Axes. The Axes is divided into equal-sized
+            boxes, and each button is left-aligned in the box. There is currently no
+            size check with the associated labels, so that long labels may overlap
+            with the next box.
-            to bottom, 'horizontal' places buttons from left to right.
+            to bottom, 'horizontal' places buttons from left to right, distributing
+            the buttons across the whole Axes. The Axes is divided into equal-sized
+            boxes, and each button is left-aligned in the box. There is currently no
+            size check with the associated labels, so that long labels may overlap
+            with the next box.
+
+            .. versionadded:: 3.10
-            .. versionadded:: 3.10
+            .. versionadded:: 3.11
-            .. versionadded:: 3.10
+            .. versionadded:: 3.11
         """
         super().__init__(ax)
 
+        _api.check_in_list(['vertical', 'horizontal'],
+                           layout_direction=layout_direction)
         _api.check_isinstance((dict, None), label_props=label_props,
                               radio_props=radio_props)
 
@@ -1619,17 +1627,32 @@ def __init__(self, ax, labels, active=0, activecolor=None, *,
         ax.set_yticks([])
         ax.set_navigate(False)
 
-        ys = np.linspace(1, 0, len(labels) + 2)[1:-1]
+        if layout_direction == 'vertical':
+            # Place buttons from top to bottom with buttons at (0.15, y) and labels
+            # at (0.25, y), where y is evenly spaced within the Axes.
+            button_ys = label_ys = np.linspace(1, 0, len(labels) + 2)[1:-1]
+            button_xs = np.full_like(button_ys, 0.15)
+            label_xs = np.full_like(label_ys, 0.25)
+            label_ha = 'left'
+            label_va = 'center'
+        else:
+            # Place buttons from left to right with buttons at (x, 0.15) and labels
+            # at (x, 0.25), where x is evenly spaced within the Axes.
+            button_xs = label_xs = np.linspace(0, 1, len(labels) + 2)[1:-1]
+            button_ys = np.full_like(button_xs, 0.15)
+            label_ys = np.full_like(label_xs, 0.25)
+            label_ha = 'center'
+            label_va = 'bottom'
 
         self._useblit = useblit and self.canvas.supports_blit
         self._background = None
 
         label_props = _expand_text_props(label_props)
         self.labels = [
-            ax.text(0.25, y, label, transform=ax.transAxes,
-                    horizontalalignment="left", verticalalignment="center",
+            ax.text(x, y, label, transform=ax.transAxes,
+                    horizontalalignment=label_ha, verticalalignment=label_va,
                     **props)
-            for y, label, props in zip(ys, labels, label_props)]
+            for x, y, label, props in zip(label_xs, label_ys, labels, label_props)]
         text_size = np.array([text.get_fontsize() for text in self.labels]) / 2
 
         radio_props = {
@@ -1642,7 +1665,7 @@ def __init__(self, ax, labels, active=0, activecolor=None, *,
         radio_props.setdefault('edgecolor', radio_props.get('color', 'black'))
         radio_props.setdefault('facecolor',
                                radio_props.pop('color', activecolor))
-        self._buttons = ax.scatter([.15] * len(ys), ys, **radio_props)
+        self._buttons = ax.scatter(button_xs, button_ys, **radio_props)
         # The user may have passed custom colours in radio_props, so we need to
         # create the radios, and modify the visibility after getting whatever
         # the user set.

diff --git a/lib/matplotlib/widgets.pyi b/lib/matplotlib/widgets.pyi
@@ -210,6 +210,7 @@ class RadioButtons(AxesWidget):
         useblit: bool = ...,
         label_props: dict[str, Any] | Sequence[dict[str, Any]] | None = ...,
         radio_props: dict[str, Any] | None = ...,
+        layout_direction: Literal["vertical", "horizontal"] = ...,
     ) -> None: ...
     def set_label_props(self, props: dict[str, Any]) -> None: ...
     def set_radio_props(self, props: dict[str, Any]) -> None: ...