1 files changed, 94 insertions, 0 deletions
diff --git a/src/embedders.rs b/src/embedders.rs
new file mode 100644
index 0000000..a8d34b4
--- /dev/null
+++ b/src/embedders.rs
@@ -0,0 +1,94 @@
+use std::path::PathBuf;
+
+pub trait MetricElem {
+    fn dist(&self, _: &Self) -> f64;
+}
+
+impl MetricElem for f64 {
+    fn dist(&self, b: &f64) -> f64 {
+        (self - b).abs()
+    }
+}
+
+pub trait EmbedderT {
+    type Embedding: MetricElem;
+
+    fn embed(&mut self, _: &[PathBuf]) -> Result<Vec<Self::Embedding>, String>;
+}
+
+pub struct BrightnessEmbedder;
+impl EmbedderT for BrightnessEmbedder {
+    type Embedding = f64;
+
+    fn embed(&mut self, paths: &[PathBuf]) -> Result<Vec<f64>, String> {
+        paths
+            .iter()
+            .map(|p| {
+                println!("{:?}", p);
+                let im = image::open(p).map_err(|e| e.to_string())?;
+                let num_bytes = 3 * (im.height() * im.width());
+
+                if num_bytes == 0 {
+                    Err("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)
+            })
+            .try_collect()
+    }
+}
+
+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 struct HueEmbedder;
+impl EmbedderT for HueEmbedder {
+    type Embedding = f64; // TODO anderes Ding was Winkel vergleicht
+
+    fn embed(&mut self, paths: &[PathBuf]) -> Result<Vec<f64>, String> {
+        paths
+            .iter()
+            .map(|p| {
+                let im = image::open(p).map_err(|e| e.to_string())?;
+                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 mut 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 < 0. {
+                    hue += 6.;
+                }
+
+                if hue != hue {
+                    Err("Encountered NaN hue, possibly because of a colorless or empty image")?;
+                }
+
+                Ok(hue)
+            })
+            .try_collect()
+    }
+}