Implement sierra

1 files changed, 44 insertions, 44 deletions

diff --git a/src/main.rs b/src/main.rs
index 46e2063..2595f78 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,74 +7,74 @@ fn dither_atkinson(image: &mut RgbImage) {
     let (width, height) = image.dimensions();
     let mut error: Vec<f32> = vec![0.; (3 * width) as usize];
 
-    for y in 0..height {
-        for x in 0..width {
-            let Rgb([r, g, b]) = image.get_pixel(x, y);
-            let pixel = (*r as u32 + *g as u32 + *b as u32) as f32 / 3.;
-            let err_pos: u32 = (y * width + x) % (3 * width);
+    for (x, y, mut pixel_) in &mut image.enumerate_pixels_mut() {
+        let Rgb([r, g, b]) = pixel_;
+        let pixel = (*r as u32 + *g as u32 + *b as u32) as f32 / 3.;
+        let err_pos: u32 = (y * width + x) % (3 * width);
 
-            let (pixel, err) = if (pixel + error[err_pos as usize]) > 127. {
-                (255, (pixel + error[err_pos as usize] - 255.) / 8.)
-            } else {
-                (0, (pixel + error[err_pos as usize]) / 8.)
-            };
+        let (pixel, err) = if (pixel + error[err_pos as usize]) > 127. {
+            (255, (pixel + error[err_pos as usize] - 255.) / 8.)
+        } else {
+            (0, (pixel + error[err_pos as usize]) / 8.)
+        };
 
-            error[err_pos as usize] = 0.;
-            error[((err_pos + 1) % (3 * width)) as usize] += err;
-            error[((err_pos + 2) % (3 * width)) as usize] += err;
-            error[((err_pos + width + 1) % (3 * width)) as usize] += err;
-            error[((err_pos + width - 1) % (3 * width)) as usize] += err;
-            error[((err_pos + width) % (3 * width)) as usize] += err;
-            error[((err_pos + 2 * width) % (3 * width)) as usize] += err;
+        error[err_pos as usize] = 0.;
+        error[((err_pos + 1) % (3 * width)) as usize] += err;
+        error[((err_pos + 2) % (3 * width)) as usize] += err;
+        error[((err_pos + width + 1) % (3 * width)) as usize] += err;
+        error[((err_pos + width - 1) % (3 * width)) as usize] += err;
+        error[((err_pos + width) % (3 * width)) as usize] += err;
+        error[((err_pos + 2 * width) % (3 * width)) as usize] += err;
 
-            image.put_pixel(x, y, image::Rgb([pixel, pixel, pixel]));
-        }
+        *pixel_ = image::Rgb([pixel, pixel, pixel]);
     }
 }
 
-fn dither_atkinson_1_level(image: &mut RgbImage) {
+fn dither_sierra(image: &mut RgbImage) {
     let (width, height) = image.dimensions();
     let mut error: Vec<f32> = vec![0.; (3 * width) as usize];
 
-    for y in 0..height {
-        for x in 0..width {
-            let Rgb([r, g, b]) = image.get_pixel(x, y);
-            let pixel = (*r as u32 + *g as u32 + *b as u32) as f32 / 3.;
-            let err_pos: u32 = (y * width + x) % (3 * width);
+    for (x, y, mut pixel_) in &mut image.enumerate_pixels_mut() {
+        let Rgb([r, g, b]) = pixel_;
+        let pixel = (*r as u32 + *g as u32 + *b as u32) as f32 / 3.;
+        let err_pos: u32 = (y * width + x) % (3 * width);
 
-            let (pixel, err) = if (pixel + error[err_pos as usize]) > 127. {
-                (255, (pixel - 255.) / 8.)
-            } else {
-                (0, pixel / 8.)
-            };
+        let (pixel, err) = if (pixel + error[err_pos as usize]) > 127. {
+            (255, (pixel + error[err_pos as usize] - 255.) / 32.)
+        } else {
+            (0, (pixel + error[err_pos as usize]) / 32.)
+        };
 
-            error[err_pos as usize] = 0.;
-            error[((err_pos + 1) % (3 * width)) as usize] += err;
-            error[((err_pos + 2) % (3 * width)) as usize] += err;
-            error[((err_pos + width + 1) % (3 * width)) as usize] += err;
-            error[((err_pos + width - 1) % (3 * width)) as usize] += err;
-            error[((err_pos + width) % (3 * width)) as usize] += err;
-            error[((err_pos + 2 * width) % (3 * width)) as usize] += err;
+        error[err_pos as usize] = 0.;
+        error[((err_pos + 1) % (3 * width)) as usize] += 5. * err;
+        error[((err_pos + 2) % (3 * width)) as usize] += 3. * err;
+        error[((err_pos + width + 2) % (3 * width)) as usize] += 2. * err;
+        error[((err_pos + width + 1) % (3 * width)) as usize] += 4. * err;
+        error[((err_pos + width) % (3 * width)) as usize] += 5. * err;
+        error[((err_pos + width - 1) % (3 * width)) as usize] += 4. * err;
+        error[((err_pos + width - 2) % (3 * width)) as usize] += 2. * err;
+        error[((err_pos + 2 * width + 1) % (3 * width)) as usize] += 2. * err;
+        error[((err_pos + 2 * width) % (3 * width)) as usize] += 3. * err;
+        error[((err_pos + 2 * width - 1) % (3 * width)) as usize] += 2. * err;
 
-            image.put_pixel(x, y, image::Rgb([pixel, pixel, pixel]));
-        }
+        *pixel_ = image::Rgb([pixel, pixel, pixel]);
     }
 }
 
 fn main() -> Result<(), image::ImageError> {
     let args: Vec<String> = env::args().collect();
 
-    let image_path = format!("{}.jpg", &args[1]);
-    let image_out = format!("{}_dithered.jpg", &args[1]);
-    let image_out_1l = format!("{}_dithered_1l.jpg", &args[1]);
+    let image_path = format!("{}.png", &args[1]);
+    let image_out = format!("{}_dithered_atkinso.jpg", &args[1]);
+    let image_out_sierra = format!("{}_dithered_sierra.jpg", &args[1]);
 
     let mut img = ImageReader::open(&image_path)?.decode()?.into_rgb8();
     dither_atkinson(&mut img);
     img.save(image_out)?;
 
     let mut img = ImageReader::open(&image_path)?.decode()?.into_rgb8();
-    dither_atkinson_1_level(&mut img);
-    img.save(image_out_1l)?;
+    dither_sierra(&mut img);
+    img.save(image_out_sierra)?;
 
     Ok(())
 }