indicate_inset transform support

rcomer · rcomer · commit c8e76438bb65 · 2024-11-22T20:13:47.000Z
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -440,7 +440,7 @@ def indicate_inset(self, bounds=None, inset_ax=None, *, transform=None,
 
         transform : `.Transform`
             Transform for the rectangle coordinates. Defaults to
-            ``ax.transAxes``, i.e. the units of *rect* are in Axes-relative
+            ``ax.transData``, i.e. the units of *rect* are in the Axes' data
             coordinates.
 
         facecolor : :mpltype:`color`, default: 'none'
diff --git a/lib/matplotlib/inset.py b/lib/matplotlib/inset.py
@@ -59,6 +59,7 @@ def __init__(self, bounds=None, inset_ax=None, zorder=None, **kwargs):
         x, y, width, height = bounds
 
         self._rectangle = Rectangle((x, y), width, height, clip_on=False, **kwargs)
+        self._rect_trans = kwargs['transform']
 
         # Connector positions cannot be calculated till the artist has been added
         # to an axes, so just make an empty list for now.
@@ -152,6 +153,10 @@ def _update_connectors(self):
         width = self._rectangle.get_width()
         height = self._rectangle.get_height()
 
+        if hasattr(self._rect_trans, '_as_mpl_transform'):
+            self._rect_trans = self._rect_trans._as_mpl_transform(self.axes)
+        self.rectangle.axes = self.axes
+
         existing_connectors = self._connectors or [None] * 4
 
         # connect the inset_axes to the rectangle
@@ -171,7 +176,7 @@ def _update_connectors(self):
                 # parent artist.
                 p = ConnectionPatch(
                     xyA=xy_inset_ax, coordsA=self._inset_ax.transAxes,
-                    xyB=xy_data, coordsB=self.axes.transData,
+                    xyB=xy_data, coordsB=self._rect_trans,
                     arrowstyle="-",
                     edgecolor=self._edgecolor, alpha=self.get_alpha(),
                     linestyle=self._linestyle, linewidth=self._linewidth)
@@ -182,7 +187,7 @@ def _update_connectors(self):
                 existing.xy1 = xy_inset_ax
                 existing.xy2 = xy_data
                 existing.coords1 = self._inset_ax.transAxes
-                existing.coords2 = self.axes.transData
+                existing.coords2 = self._rect_trans
 
         if existing is None:
             # decide which two of the lines to keep visible....
diff --git a/lib/matplotlib/tests/baseline_images/test_inset/zoom_inset_transform.png b/lib/matplotlib/tests/baseline_images/test_inset/zoom_inset_transform.png
diff --git a/lib/matplotlib/tests/test_inset.py b/lib/matplotlib/tests/test_inset.py
@@ -4,6 +4,7 @@
 
 import matplotlib.colors as mcolors
 import matplotlib.pyplot as plt
+import matplotlib.transforms as mtransforms
 from matplotlib.testing.decorators import image_comparison, check_figures_equal
 
 
@@ -104,3 +105,33 @@ def test_zoom_inset_connector_styles():
     # Make one visible connector a different style
     indicator.connectors[1].set_linestyle('dashed')
     indicator.connectors[1].set_color('blue')
+
+
+@image_comparison(['zoom_inset_transform.png'], remove_text=True, style='mpl20')
+def test_zoom_inset_transform():
+    fig, ax = plt.subplots()
+
+    ax_ins = ax.inset_axes([0.2, 0.2, 0.3, 0.15])
+    ax_ins.set_ylim([0.3, 0.6])
+    ax_ins.set_xlim([0.5, 0.9])
+
+    tr = mtransforms.Affine2D().rotate_deg(30)
+    indicator = ax.indicate_inset_zoom(ax_ins, transform=tr + ax.transData)
+    for conn in indicator.connectors:
+        conn.set_visible(True)
+
+
+def test_zoom_inset_external_transform():
+    # Smoke test that an external transform that requires an axes (i.e.
+    # Cartopy) will work.
+    class FussyDataTr:
+        def _as_mpl_transform(self, axes=None):
+            if axes is None:
+                raise ValueError("I am a fussy transform that requires an axes")
+            return axes.transData
+
+    fig, ax = plt.subplots()
+    ax_ins = ax.inset_axes([0.2, 0.2, 0.3, 0.15])
+    ax.indicate_inset_zoom(ax_ins, transform=FussyDataTr())
+
+    fig.draw_without_rendering()
