Make transforms.nonsingular handle inf and nan sensibly.

efiring · efiring · commit e356a151a7df · 2008-10-16T21:21:58.000Z
Without this, trying to plot a line with all data masked would
raise an exception via the autoscaling.

svn path=/trunk/matplotlib/; revision=6232
diff --git a/lib/matplotlib/transforms.py b/lib/matplotlib/transforms.py
@@ -2157,15 +2157,19 @@ def get_affine(self):
 
 def nonsingular(vmin, vmax, expander=0.001, tiny=1e-15, increasing=True):
     '''
-    Ensure the endpoints of a range are not too close together.
+    Ensure the endpoints of a range are finite and not too close together.
 
     "too close" means the interval is smaller than 'tiny' times
     the maximum absolute value.
 
     If they are too close, each will be moved by the 'expander'.
     If 'increasing' is True and vmin > vmax, they will be swapped,
     regardless of whether they are too close.
+
+    If either is inf or -inf or nan, return - expander, expander.
     '''
+    if (not np.isfinite(vmin)) or (not np.isfinite(vmax)):
+        return -expander, expander
     swapped = False
     if vmax < vmin:
         vmin, vmax = vmax, vmin
