cairo backend: default to pycairo

lazka · lazka · commit 1ad4eddc0034 · 2018-12-31T23:44:31.000+01:00
As seen in #13042 it's a bit faster than cairocffi and it also takes 50 ms less time to import here. Also the GTK3Cairo backend requires pycairo, so there is a good chance it's already loaded anyway for that case.
diff --git a/lib/matplotlib/backends/backend_cairo.py b/lib/matplotlib/backends/backend_cairo.py
@@ -11,21 +11,18 @@
 
 import numpy as np
 
-# cairocffi is more widely compatible than pycairo so try it first.
 try:
-    import cairocffi as cairo
+    import cairo
+    if cairo.version_info < (1, 11, 0):
+        # Introduced create_for_data for Py3.
+        raise ImportError
 except ImportError:
     try:
-        import cairo
+        import cairocffi as cairo
     except ImportError:
-        raise ImportError("cairo backend requires that cairocffi or pycairo "
-                          "is installed")
-    else:
-        if cairo.version_info < (1, 11, 0):
-            # Introduced create_for_data for Py3.
-            raise ImportError(
-                "cairo {} is installed; cairo>=1.11.0 is required"
-                .format(cairo.version))
+        raise ImportError(
+            "cairo backend requires that pycairo>=1.11.0 or cairocffi"
+            "is installed")
 
 backend_version = cairo.version
 
