Better ImportError message when trying to use Gtk3Agg backend without cairo

timhoffm · timhoffm · commit 3c451847b852 · 2019-04-23T15:22:29.000+02:00
diff --git a/lib/matplotlib/backends/backend_gtk3agg.py b/lib/matplotlib/backends/backend_gtk3agg.py
@@ -1,7 +1,11 @@
 import numpy as np
 
 from .. import cbook
-from . import backend_agg, backend_cairo, backend_gtk3
+try:
+    from . import backend_cairo
+except ImportError as e:
+    raise ImportError('backend Gtk3Agg requires cairo') from e
+from . import backend_agg, backend_gtk3
 from .backend_cairo import cairo
 from .backend_gtk3 import Gtk, _BackendGTK3
 from matplotlib import transforms
