Emoji avg color ignores blank pixels

spritefire/src/emoji.rs

@@ -14,16 +14,94 @@ impl From<(DynamicImage, String)> for Emoji {
         let (image, symbol) = value;
 
         // use thumbnail technique to find average color
-        let thumbnail = image.thumbnail_exact(1, 1);
-        let pixel = thumbnail.get_pixel(0, 0);
+        let mut avg_r = 0;
+        let mut avg_g = 0;
+        let mut avg_b = 0;
+        let mut pix_count = 0;
 
-        let avg_r = pixel[0];
-        let avg_g = pixel[1];
-        let avg_b = pixel[2];
+        let (x_dim, y_dim) = image.dimensions();
+
+        for y in 0..y_dim {
+            for j in 0..x_dim {
+                let pixel = image.get_pixel(j, y).0;
+
+                if pixel[3] > 0 {
+                    pix_count += 1;
+
+                    avg_r += pixel[0] as u64;
+                    avg_g += pixel[1] as u64;
+                    avg_b += pixel[2] as u64;
+                }
+            }
+        }
+
+        let avg_r = avg_r as f64 / pix_count as f64;
+        let avg_g = avg_g as f64 / pix_count as f64;
+        let avg_b = avg_b as f64 / pix_count as f64;
 
         Self {
             symbol,
             color: [avg_r as u8, avg_g as u8, avg_b as u8],
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::{fmt::format, fs};
+
+    use image::{GenericImageView, Pixel};
+
+    #[test]
+    fn thumbnail() {
+        let img =
+            image::open("/home/twitu/Code/spritefire/assets/sprites_512/emoji_u1f3aa.png").unwrap();
+        dbg!(img.dimensions()); // 512, 512
+        const DIMS: [u32; 10] = [512, 256, 128, 64, 32, 16, 8, 4, 2, 1];
+        let mut avg_r = 0;
+        let mut avg_g = 0;
+        let mut avg_b = 0;
+        let mut pix_count = 0;
+        for dim in DIMS {
+            let thumb = img.thumbnail(dim, dim);
+            let mut colors: String = String::new();
+
+            for y in (0..dim) {
+                for j in (0..dim) {
+                    let pixel = thumb.get_pixel(j, y).0;
+                    colors.push_str(
+                        &format!(
+                            "{:02x}{:02x}{:02x}{:02x} ",
+                            pixel[0], pixel[1], pixel[2], pixel[3]
+                        )
+                        .to_string(),
+                    );
+
+                    if dim == 512 {
+                        if pixel[3] > 0 {
+                            pix_count += 1;
+
+                            avg_r += pixel[0] as u64;
+                            avg_g += pixel[1] as u64;
+                            avg_b += pixel[2] as u64;
+                        }
+                    }
+                }
+                colors.push('\n');
+            }
+
+            fs::write(format!("emoji_{}.txt", dim), colors).unwrap();
+            thumb.save(format!("emoji_{}.png", dim)).unwrap();
+        }
+        dbg!(avg_r, avg_g, avg_b);
+        let avg_r = (avg_r as f64 / pix_count as f64) as u8;
+        let avg_g = (avg_g as f64 / pix_count as f64) as u8;
+        let avg_b = (avg_b as f64 / pix_count as f64) as u8;
+
+        fs::write(
+            "emoji_avg.txt",
+            format!("{:02x}{:02x}{:02x} ", avg_r, avg_g, avg_b),
+        )
+        .unwrap();
+    }
+}