Reduce allocations using bytemuck's cast_vec

Author: SpaceManiac

crates/dmm-tools/Cargo.toml

@@ -16,7 +16,7 @@ either = "1.13.0"
 
 [dependencies.bytemuck]
 version = "1.19.0"
-features = ["derive"]
+features = ["derive", "extern_crate_alloc"]
 
 [dependencies.bumpalo]
 version = "3.16.0"

crates/dmm-tools/src/dmi.rs

@@ -133,10 +133,8 @@ impl Image {
             width: bitmap.width as u32,
             height: bitmap.height as u32,
             data: {
-                let cast_input = bytemuck::cast_slice(bitmap.buffer.as_slice());
-                let mut arr = Array2::default((bitmap.width, bitmap.height));
-                arr.as_slice_mut().unwrap().copy_from_slice(cast_input);
-                arr
+                let cast_input = bytemuck::allocation::cast_vec(bitmap.buffer);
+                Array2::from_shape_vec((bitmap.width, bitmap.height), cast_input).unwrap()
             },
         }
     }

crates/dmm-tools/src/dmi/render.rs

@@ -180,7 +180,7 @@ impl<'a> IconRenderer<'a> {
         for frame in range {
             self.render_dirs(icon_state, &mut canvas, frame as u32);
 
-            let mut pixels = bytemuck::cast_slice(canvas.data.as_slice().unwrap()).to_owned();
+            let mut pixels = bytemuck::cast_slice_mut(canvas.data.as_slice_mut().unwrap());
             let mut gif_frame =
                 gif::Frame::from_rgba(canvas.width as u16, canvas.height as u16, &mut pixels);
             // gif::Frame delays are measured in "Frame delay in units of 10 ms."