Use path extents to get path autoscale limits

dstansby · dstansby · commit a105bbae1157 · 2021-10-08T18:24:17.000+01:00
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -2374,23 +2374,28 @@ def _update_patch_limits(self, patch):
                 ((not patch.get_width()) and (not patch.get_height()))):
             return
         p = patch.get_path()
-        vertices = p.vertices if p.codes is None else p.vertices[np.isin(
-            p.codes, (mpath.Path.CLOSEPOLY, mpath.Path.STOP), invert=True)]
-        if not vertices.size:
-            return
-        patch_trf = patch.get_transform()
-        updatex, updatey = patch_trf.contains_branch_seperately(self.transData)
-        if not (updatex or updatey):
-            return
-        if self.name != "rectilinear":
-            # As in _update_line_limits, but for axvspan.
-            if updatex and patch_trf == self.get_yaxis_transform():
-                updatex = False
-            if updatey and patch_trf == self.get_xaxis_transform():
-                updatey = False
-        trf_to_data = patch_trf - self.transData
-        xys = trf_to_data.transform(vertices)
-        self.update_datalim(xys, updatex=updatex, updatey=updatey)
+        # Get all vertices on the path
+        # Loop through each sement to get extrema (as opposed to control points)
+        # for Bezier curve sections
+        vertices = []
+        for curve, code in p.iter_bezier():
+            _, dzeros = curve.axis_aligned_extrema()
+            # as can the ends of the curve
+            vertices.append(curve([0, *dzeros, 1]))
+
+        if len(vertices):
+            vertices = np.row_stack(vertices)
+
+        xys = patch.get_patch_transform().transform(vertices)
+        if patch.get_data_transform() != self.transData:
+            patch_to_data = (patch.get_data_transform() -
+                             self.transData)
+            xys = patch_to_data.transform(xys)
+
+        updatex, updatey = patch.get_transform().\
+            contains_branch_seperately(self.transData)
+        self.update_datalim(xys, updatex=updatex,
+                            updatey=updatey)
 
     def add_table(self, tab):
         """
