From b7a01f5a79eca2de7b581aa192b023778b122787 Mon Sep 17 00:00:00 2001
From: Rory McCann <rory@technomancy.org>
Date: Sat, 5 Aug 2017 12:13:10 +0200
Subject: [PATCH] more

---
 src/algorithm/coord_change.rs | 70 +++++++++++++++++++++++++++++++++++
 src/algorithm/mod.rs          |  2 +
 2 files changed, 72 insertions(+)
 create mode 100644 src/algorithm/coord_change.rs

diff --git a/src/algorithm/coord_change.rs b/src/algorithm/coord_change.rs
new file mode 100644
index 0000000000..8c58e15f1f
--- /dev/null
+++ b/src/algorithm/coord_change.rs
@@ -0,0 +1,70 @@
+use num_traits::{Float};
+use types::{Point, Polygon, LineString, Line, MultiPoint, MultiPolygon, MultiLineString};
+
+pub trait CoordChange<T> {
+    fn coord_change(&self, func: &Fn(&(T, T)) -> (T, T)) -> Self where T: Float;
+
+}
+
+impl<T: Float> CoordChange<T> for Point<T> {
+    fn coord_change(&self, func: &Fn(&(T, T)) -> (T, T)) -> Point<T>
+    {
+        let new_point = func(&(self.0.x, self.0.y));
+        Point::new(new_point.0, new_point.1)
+    }
+}
+
+impl<T: Float> CoordChange<T> for LineString<T> {
+    fn coord_change(&self, func: &Fn(&(T, T)) -> (T, T)) -> Self
+    {
+        LineString(self.0.iter().map(|p| p.coord_change(func)).collect())
+    }
+}
+
+impl<T: Float> CoordChange<T> for Polygon<T> {
+    fn coord_change(&self, func: &Fn(&(T, T)) -> (T, T)) -> Self
+    {
+        Polygon::new(self.exterior.coord_change(func), self.interiors.iter().map(|l| l.coord_change(func)).collect())
+    }
+}
+
+
+mod test {
+    use super::*;
+
+    #[test]
+    fn point() {
+        let p = Point::new(10., 10.);
+        let new_p = p.coord_change(&|&(x, y)| (x+10., y+100.));
+        assert_eq!(new_p.x(), 20.);
+        assert_eq!(new_p.y(), 110.);
+    }
+
+    #[test]
+    fn linestring() {
+        let line1: LineString<f32> = LineString(vec![Point::new(0., 0.), Point::new(1., 2.).into()]);
+        let line2 = line1.coord_change(&|&(x, y)| (x+10., y-100.));
+        assert_eq!(line2.0[0], Point::new(10., -100.));
+        assert_eq!(line2.0[1], Point::new(11., -98.));
+
+    }
+
+    #[test]
+    fn polygon() {
+        let exterior = LineString(vec![Point::new(0., 0.), Point::new(1., 1.),
+                                       Point::new(1., 0.), Point::new(0., 0.)]);
+        let interiors = vec![LineString(vec![Point::new(0.1, 0.1), Point::new(0.9, 0.9),
+                                             Point::new(0.9, 0.1), Point::new(0.1, 0.1)])];
+        let p = Polygon::new(exterior, interiors);
+
+        let p2 = p.coord_change(&|&(x, y)| (x+10., y-100.));
+
+        let exterior2 = LineString(vec![Point::new(10., -100.), Point::new(11., -99.),
+                                       Point::new(11., -100.), Point::new(10., -100.)]);
+        let interiors2 = vec![LineString(vec![Point::new(10.1, -99.9), Point::new(10.9, -99.1),
+                                             Point::new(10.9, -99.9), Point::new(10.1, -99.)])];
+        let expected_p2 = Polygon::new(exterior2, interiors2);
+
+        assert_eq!(p2, expected_p2);
+    }
+}
diff --git a/src/algorithm/mod.rs b/src/algorithm/mod.rs
index 24e0abd592..242d8f0f3c 100644
--- a/src/algorithm/mod.rs
+++ b/src/algorithm/mod.rs
@@ -30,3 +30,5 @@ pub mod extremes;
 pub mod rotate;
 /// Translates a geometry along the given offsets.
 pub mod translate;
+/// Apply a function to all coordinates
+pub mod coord_change;