Add degrees getter for cardinal directions.

src/core.rs

@@ -1,5 +1,6 @@
 use std::{
     cmp::{max, min},
+    f32::consts::PI,
     fmt::Display,
     marker::PhantomData,
     ops::{Add, AddAssign, Sub, SubAssign},
@@ -282,6 +283,15 @@ impl CardinalDirection {
             _ => East,
         }
     }
+
+    pub fn angle(&self) -> Angle {
+        match self {
+            CardinalDirection::North => Angle::Radians(PI / 2.),
+            CardinalDirection::East => Angle::Radians(0.),
+            CardinalDirection::South => Angle::Radians(-PI / 2.),
+            CardinalDirection::West => Angle::Radians(PI),
+        }
+    }
 }
 
 impl From<Angle> for CardinalDirection {