Fix draw_quad_mesh for backends without urls support.

QuLogic · QuLogic · commit aa67e381e715 · 2020-05-07T19:21:34.000-04:00
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -9,6 +9,7 @@
 line segments).
 """
 
+import inspect
 import math
 from numbers import Number
 import numpy as np
@@ -2042,10 +2043,26 @@ def draw(self, renderer):
             renderer.draw_gouraud_triangles(
                 gc, triangles, colors, transform.frozen())
         else:
-            renderer.draw_quad_mesh(
-                gc, transform.frozen(), self._meshWidth, self._meshHeight,
-                coordinates, offsets, transOffset, self.get_facecolor(),
-                self._antialiased, self.get_edgecolors(), urls=self.get_urls())
+            try:
+                sig = inspect.signature(renderer.draw_quad_mesh)
+            except ValueError:
+                # Compiled backends like Agg don't have a signature, but also
+                # don't support urls anyway.
+                use_urls = False
+            else:
+                use_urls = 'urls' in sig.parameters
+            if use_urls:
+                renderer.draw_quad_mesh(
+                    gc, transform.frozen(), self._meshWidth, self._meshHeight,
+                    coordinates, offsets, transOffset, self.get_facecolor(),
+                    self._antialiased, self.get_edgecolors(),
+                    urls=self.get_urls())
+            else:
+                # This backend does not support storing urls in the QuadMesh.
+                renderer.draw_quad_mesh(
+                    gc, transform.frozen(), self._meshWidth, self._meshHeight,
+                    coordinates, offsets, transOffset, self.get_facecolor(),
+                    self._antialiased, self.get_edgecolors())
         gc.restore()
         renderer.close_group(self.__class__.__name__)
         self.stale = False
