From da9b2ad1310e1db0ccb26a53181fa7f9b9033d04 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@tavianator.com>
Date: Sat, 2 May 2020 13:56:09 -0400
Subject: frontier/image: Implement image frontiers

---
 src/frontier.rs | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 70 insertions(+), 1 deletion(-)

(limited to 'src/frontier.rs')

diff --git a/src/frontier.rs b/src/frontier.rs
index 2c6f43a..1c5a173 100644
--- a/src/frontier.rs
+++ b/src/frontier.rs
@@ -1,6 +1,13 @@
 //! Frontiers on which to place pixels.
 
-use crate::color::Rgb8;
+pub mod image;
+
+use crate::color::{ColorSpace, Rgb8};
+use crate::metric::kd::Cartesian;
+use crate::metric::soft::SoftDelete;
+use crate::metric::Metric;
+
+use std::cell::Cell;
 
 /// A frontier of pixels.
 pub trait Frontier {
@@ -16,3 +23,65 @@ pub trait Frontier {
     /// Place the given color on the frontier, and return its position.
     fn place(&mut self, rgb8: Rgb8) -> Option<(u32, u32)>;
 }
+
+/// A pixel on a frontier.
+#[derive(Debug)]
+struct Pixel<C> {
+    pos: (u32, u32),
+    color: C,
+    deleted: Cell<bool>,
+}
+
+impl<C: ColorSpace> Pixel<C> {
+    fn new(x: u32, y: u32, color: C) -> Self {
+        Self {
+            pos: (x, y),
+            color,
+            deleted: Cell::new(false),
+        }
+    }
+
+    fn delete(&self) {
+        self.deleted.set(true);
+    }
+}
+
+impl<C: Metric> Metric<Pixel<C>> for C {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &Pixel<C>) -> Self::Distance {
+        self.distance(&other.color)
+    }
+}
+
+impl<C: Metric<[f64]>> Metric<[f64]> for Pixel<C> {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &[f64]) -> Self::Distance {
+        self.color.distance(other)
+    }
+}
+
+impl<C: Metric> Metric for Pixel<C> {
+    type Distance = C::Distance;
+
+    fn distance(&self, other: &Pixel<C>) -> Self::Distance {
+        self.color.distance(&other.color)
+    }
+}
+
+impl<C: Cartesian> Cartesian for Pixel<C> {
+    fn dimensions(&self) -> usize {
+        self.color.dimensions()
+    }
+
+    fn coordinate(&self, i: usize) -> f64 {
+        self.color.coordinate(i)
+    }
+}
+
+impl<C> SoftDelete for Pixel<C> {
+    fn is_deleted(&self) -> bool {
+        self.deleted.get()
+    }
+}
-- 
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