Merge pull request #11536 from matplotlib/auto-backport-of-pr-11532-on-v2.2.2-doc

dstansby · web-flow · commit 7f4a8d41f930 · 2018-07-04T12:29:09.000+01:00
Backport PR #11532 on branch v2.2.2-doc
diff --git a/examples/units/basic_units.py b/examples/units/basic_units.py
@@ -298,13 +298,21 @@ def __call__(self, operation, units):
 
 # radians formatting
 def rad_fn(x, pos=None):
-    n = int((x / np.pi) * 2.0 + 0.25)
+    if x >= 0:
+        n = int((x / np.pi) * 2.0 + 0.25)
+    else:
+        n = int((x / np.pi) * 2.0 - 0.25)
+
     if n == 0:
         return '0'
     elif n == 1:
         return r'$\pi/2$'
     elif n == 2:
         return r'$\pi$'
+    elif n == -1:
+        return r'$-\pi/2$'
+    elif n == -2:
+        return r'$-\pi$'
     elif n % 2 == 0:
         return r'$%s\pi$' % (n//2,)
     else:
