From 073123ce1e65c71689e4c41a6009cbba6340fa3a Mon Sep 17 00:00:00 2001
From: Nicolas Silva <nical@fastmail.com>
Date: Fri, 8 Dec 2017 10:15:58 +0100
Subject: [PATCH] Implement Neg for Angle.

---
 src/rotation.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/rotation.rs b/src/rotation.rs
index 39f7d23..e2da5ac 100644
--- a/src/rotation.rs
+++ b/src/rotation.rs
@@ -110,6 +110,13 @@ impl<T: Clone + MulAssign<T>> MulAssign<T> for Angle<T> {
     }
 }
 
+impl<T: Neg<Output=T>> Neg for Angle<T> {
+    type Output = Self;
+    fn neg(self) -> Self {
+        Angle::radians(-self.radians)
+    }
+}
+
 
 define_matrix! {
     /// A transform that can represent rotations in 2d, represented as an angle in radians.