Fix pan/zoom crashing when widget lock is unavailable

kianelbo · kianelbo · commit c063363fff74 · 2022-06-30T23:14:19.000+04:30
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
@@ -3042,6 +3042,9 @@ def pan(self, *args):
 
         Pan with left button, zoom with right.
         """
+        if not self.canvas.widgetlock.available(self):
+            self.set_message("pan unavailable")
+            return
         if self.mode == _Mode.PAN:
             self.mode = _Mode.NONE
             self.canvas.widgetlock.release(self)
@@ -3094,6 +3097,9 @@ def release_pan(self, event):
         self.push_current()
 
     def zoom(self, *args):
+        if not self.canvas.widgetlock.available(self):
+            self.set_message("zoom unavailable")
+            return
         """Toggle zoom to rect mode."""
         if self.mode == _Mode.ZOOM:
             self.mode = _Mode.NONE
