1 files changed, 50 insertions, 0 deletions
diff --git a/src/ocr.rs b/src/ocr.rs
new file mode 100644
index 0000000..bc7e535
--- /dev/null
+++ b/src/ocr.rs
@@ -0,0 +1,50 @@
+use image::{DynamicImage, GrayImage, ImageFormat};
+use imageproc::template_matching::MatchTemplateMethod;
+
+const REFERENCE_PNGS: [&[u8]; 10] = [
+    include_bytes!("../data/0.png"),
+    include_bytes!("../data/1.png"),
+    include_bytes!("../data/2.png"),
+    include_bytes!("../data/3.png"),
+    include_bytes!("../data/4.png"),
+    include_bytes!("../data/5.png"),
+    include_bytes!("../data/6.png"),
+    include_bytes!("../data/7.png"),
+    include_bytes!("../data/8.png"),
+    include_bytes!("../data/9.png"),
+];
+
+fn x_matches(image: &GrayImage, template: &GrayImage) -> Vec<u32> {
+    let match_values = imageproc::template_matching::match_template(
+        image,
+        template,
+        MatchTemplateMethod::CrossCorrelationNormalized,
+    );
+    match_values
+        .enumerate_pixels()
+        .filter(|(_x, _y, pix)| pix.0[0] > 0.9)
+        .map(|(x, _y, _pix)| x)
+        .collect()
+}
+
+pub fn ocr(image: DynamicImage) -> u32 {
+    let grayscale_image = image::imageops::grayscale(&image);
+    let mut digit_x_positions: Vec<(u8, u32)> = (0..10)
+        .flat_map(|i| {
+            let png_i =
+                image::load_from_memory_with_format(REFERENCE_PNGS[i as usize], ImageFormat::Png)
+                    .unwrap();
+            let grey_png_i = image::imageops::grayscale(&png_i);
+            x_matches(&grayscale_image, &grey_png_i)
+                .into_iter()
+                .map(move |x| (i, x))
+        })
+        .collect();
+    digit_x_positions.sort_by_key(|&(_i, x)| x);
+    let digits: String = digit_x_positions
+        .into_iter()
+        .map(|(i, _x)| format!("{}", i))
+        .collect();
+    dbg!(&digits);
+    digits.parse().unwrap()
+}