add palette selection; make image request extractor

src/api.rs

@@ -1,11 +1,12 @@
 use crate::display::EInkPanel;
 use crate::imageproc::{DitherMethod, DitherPalette, EInkImage};
-use axum::extract::Multipart;
+use axum::async_trait;
+use axum::extract::{FromRequest, Multipart, State};
 use axum::http::{header, StatusCode};
 use axum::response::IntoResponse;
-use axum::{extract::State, response::Response, routing::post, Router};
+use axum::{response::Response, routing::post, Router};
 use image::{ImageReader, RgbImage};
-use std::io::{BufWriter, Cursor};
+use std::io::Cursor;
 use std::str;
 use std::str::FromStr;
 use std::sync::Arc;
@@ -98,8 +99,15 @@ struct ImageRequest {
     palette: DitherPalette,
 }
 
-impl ImageRequest {
-    async fn from_multipart(mut parts: Multipart) -> Result<Self, AppError> {
+#[async_trait]
+impl<S> FromRequest<S> for ImageRequest
+where
+    S: Send + Sync,
+{
+    type Rejection = AppError;
+
+    async fn from_request(req: axum::extract::Request, state: &S) -> Result<Self, Self::Rejection> {
+        let mut parts = Multipart::from_request(req, state).await?;
         let mut img = None;
         let mut palette = None;
         let mut dither_method = None;
@@ -141,13 +149,12 @@ impl ImageRequest {
 #[instrument(skip(ctx))]
 async fn set_image(
     State(ctx): State<Context>,
-    parts: Multipart,
+    img_req: ImageRequest,
 ) -> Result<impl IntoResponse, AppError> {
-    let call = ImageRequest::from_multipart(parts).await?;
-    let mut buf = EInkImage::new(call.palette.value().to_vec());
+    let mut buf = EInkImage::new(img_req.palette.value().to_vec());
     {
-        let mut dither = call.dither_method.get_ditherer();
-        dither.dither(&call.image, &mut buf);
+        let mut dither = img_req.dither_method.get_ditherer();
+        dither.dither(&img_req.image, &mut buf);
     }
     let cmd = DisplaySetCommand { img: Box::new(buf) };
     ctx.display_channel
@@ -158,12 +165,11 @@ async fn set_image(
 
 /// generates a dithered image based on the given image and the dithering parameters.
 /// Can be used to see how the dithering and palette choices affect the result.
-async fn preview_image(parts: Multipart) -> Result<impl IntoResponse, AppError> {
-    let call = ImageRequest::from_multipart(parts).await?;
-    let mut buf = EInkImage::new(call.palette.value().to_vec());
+async fn preview_image(img_req: ImageRequest) -> Result<impl IntoResponse, AppError> {
+    let mut buf = EInkImage::new(img_req.palette.value().to_vec());
     {
-        let mut dither = call.dither_method.get_ditherer();
-        dither.dither(&call.image, &mut buf);
+        let mut dither = img_req.dither_method.get_ditherer();
+        dither.dither(&img_req.image, &mut buf);
     }
     // Convert buf into a png image.
     let img = buf.into_rgbimage();

src/imageproc.rs

@@ -37,10 +37,11 @@ pub enum DitherPalette {
 }
 
 impl DitherPalette {
-    pub fn value(&self) -> &[Srgb] {
+    #[must_use]
+    pub const fn value(&self) -> &[Srgb] {
         match self {
             Self::Default => &DISPLAY_PALETTE,
-            Self::Simple => &DISPLAY_PALETTE, // FIXME: use simple pallete based on binary.
+            Self::Simple => &SIMPLE_PALETTE, // FIXME: use simple pallete based on binary.
         }
     }
 }
@@ -94,7 +95,10 @@ impl EInkImage {
     pub fn into_rgbimage(&self) -> RgbImage {
         RgbImage::from_fn(self.buf.width(), self.buf.height(), |x, y| {
             let idx = self.buf.get_pixel(x, y).0[0];
-            let disp_color = self.palette.get(idx as usize).unwrap();
+            let disp_color = self
+                .palette
+                .get(idx as usize)
+                .expect("Palette will never be out of bounds");
             let arr: [u8; 3] = disp_color.into_format().into();
             imgRgb(arr)
         })
@@ -174,7 +178,7 @@ fn compute_error_adjusted_color(orig: &Lab, err: &Lab, weight: f32) -> Lab {
 /// ``DiffusionPoint`` is part of the diffusion matrix, represented by a shift in x and y and an error
 /// scaling factor.
 #[derive(Debug)]
-struct DiffusionPoint {
+pub struct DiffusionPoint {
     xshift: i32,
     yshift: i32,
     scale: f32,