Write image buffer backwards

src/main.rs

@@ -70,7 +70,7 @@ fn load_wallpaper(path: &Path) -> eyre::Result<GrayAlphaImage> {
 
     match image_dimensions {
         (SCREEN_W, SCREEN_H) => {}
-        (SCREEN_H, SCREEN_W) => image = image.rotate90().flipv(),
+        (SCREEN_H, SCREEN_W) => image = image.rotate270(),
         _ => bail!("Image must be {SCREEN_W}x{SCREEN_H}"),
     }
 
@@ -119,7 +119,7 @@ fn image_to_offimage_buffer(image: GrayAlphaImage) -> eyre::Result<Box<[u8; IOCT
     );
 
     // Iterate over pixels and copy them into `buf`.
-    for (i, pixel) in image.chunks_exact(2).enumerate() {
+    for (i, pixel) in (0..buf.len()).rev().zip(image.chunks_exact(2)) {
         let &[gray, alpha] = pixel else {
             unreachable!()
         };