1 files changed, 98 insertions, 0 deletions
diff --git a/src/pure_embedders.rs b/src/pure_embedders.rs
new file mode 100644
index 0000000..0f0c3ab
--- /dev/null
+++ b/src/pure_embedders.rs
@@ -0,0 +1,98 @@
+use anyhow::{bail, Result};
+use serde::{Deserialize, Serialize};
+use std::path::Path;
+
+use crate::{MetricElem, EmbedderT};
+
+pub(crate) struct BrightnessEmbedder;
+impl EmbedderT for BrightnessEmbedder {
+    type Embedding = f64;
+    const NAME: &'static str = "Brightness";
+
+    fn embed(&self, path: &Path) -> Result<f64> {
+        let im = image::open(path)?;
+        let num_bytes = 3 * (im.height() * im.width());
+
+        if num_bytes == 0 {
+            bail!("Encountered NaN brightness, due to an empty image");
+        }
+
+        Ok(im.to_rgb8()
+            .iter()
+            .map(|e| *e as u64)
+            .sum::<u64>() as f64 / num_bytes as f64)
+    }
+}
+
+#[repr(transparent)]
+#[derive(Serialize, Deserialize)]
+pub(crate) struct Hue (f64);
+impl MetricElem for Hue {
+    fn dist(&self, b: &Hue) -> f64 {
+        let d = self.0.dist(&b.0);
+        d.min(6.-d)
+    }
+}
+pub(crate) struct HueEmbedder;
+impl EmbedderT for HueEmbedder {
+    type Embedding = Hue;
+    const NAME: &'static str = "Hue";
+
+    fn embed(&self, path: &Path) -> Result<Hue> {
+        let im = image::open(path)?;
+        let num_pixels = im.height() * im.width();
+        let [sr, sg, sb] = im
+            .to_rgb8()
+            .pixels()
+            .fold([0, 0, 0], |[or, og, ob], n| {
+                let [nr, ng, nb] = n.0;
+                [or + nr as u64, og + ng as u64, ob + nb as u64]
+            })
+            .map(|e| e as f64 / 255. / num_pixels as f64);
+
+        let hue =
+            if sr >= sg && sr >= sb {
+                (sg - sb) / (sr - sg.min(sb))
+            }
+            else if sg >= sb {
+                2. + (sb - sr) / (sg - sr.min(sb))
+            }
+            else {
+                4. + (sr - sg) / (sb - sr.min(sg))
+            };
+
+        if hue.is_nan() {
+            bail!("Encountered NaN hue, possibly because of a colorless or empty image");
+        }
+
+        Ok(Hue(hue))
+    }
+}
+
+impl MetricElem for (f64, f64, f64) {
+    fn dist(&self, o: &(f64, f64, f64)) -> f64 {
+        let (dr, dg, db) =
+            ((self.0 - o.0), (self.1 - o.1), (self.2 - o.2));
+        (dr*dr + dg*dg + db*db).sqrt()
+    }
+}
+pub(crate) struct ColorEmbedder;
+impl EmbedderT for ColorEmbedder {
+    type Embedding = (f64, f64, f64);
+    const NAME: &'static str = "Color";
+
+    fn embed(&self, path: &Path) -> Result<(f64, f64, f64)> {
+        let im = image::open(path)?;
+        let num_pixels = im.height() * im.width();
+        let [sr, sg, sb] = im
+            .to_rgb8()
+            .pixels()
+            .fold([0, 0, 0], |[or, og, ob], n| {
+                let [nr, ng, nb] = n.0;
+                [or + nr as u64, og + ng as u64, ob + nb as u64]
+            })
+            .map(|e| e as f64 / num_pixels as f64);
+
+        Ok((sr, sg, sb))
+    }
+}