1 files changed, 61 insertions, 0 deletions
diff --git a/src/frontier.rs b/src/frontier.rs
index 1c5a173..e1b6528 100644
--- a/src/frontier.rs
+++ b/src/frontier.rs
@@ -1,6 +1,7 @@
 //! Frontiers on which to place pixels.
 
 pub mod image;
+pub mod min;
 
 use crate::color::{ColorSpace, Rgb8};
 use crate::metric::kd::Cartesian;
@@ -8,6 +9,7 @@ use crate::metric::soft::SoftDelete;
 use crate::metric::Metric;
 
 use std::cell::Cell;
+use std::rc::Rc;
 
 /// A frontier of pixels.
 pub trait Frontier {
@@ -85,3 +87,62 @@ impl<C> SoftDelete for Pixel<C> {
         self.deleted.get()
     }
 }
+
+impl<C: Metric<[f64]>> Metric<[f64]> for Rc<Pixel<C>> {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &[f64]) -> Self::Distance {
+        (**self).distance(other)
+    }
+}
+
+impl<C: Metric> Metric<Rc<Pixel<C>>> for C {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &Rc<Pixel<C>>) -> Self::Distance {
+        self.distance(&other.color)
+    }
+}
+
+impl<C: Metric> Metric for Rc<Pixel<C>> {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &Self) -> Self::Distance {
+        (**self).distance(&**other)
+    }
+}
+
+impl<C: Cartesian> Cartesian for Rc<Pixel<C>> {
+    fn dimensions(&self) -> usize {
+        (**self).dimensions()
+    }
+
+    fn coordinate(&self, i: usize) -> f64 {
+        (**self).coordinate(i)
+    }
+}
+
+impl<C> SoftDelete for Rc<Pixel<C>> {
+    fn is_deleted(&self) -> bool {
+        (**self).is_deleted()
+    }
+}
+
+/// Return all the neighbors of a pixel location.
+fn neighbors(x: u32, y: u32) -> [(u32, u32); 8] {
+    let xm1 = x.wrapping_sub(1);
+    let ym1 = y.wrapping_sub(1);
+    let xp1 = x + 1;
+    let yp1 = y + 1;
+
+    [
+        (xm1, ym1),
+        (xm1, y),
+        (xm1, yp1),
+        (x, ym1),
+        (x, yp1),
+        (xp1, ym1),
+        (xp1, y),
+        (xp1, yp1),
+    ]
+}