Add more dithering options

showbits-thermal-printer/src/documents/xkcd/data.json

@@ -2,5 +2,6 @@
   "number": 3064,
   "title": "Lungfish",
   "alt": "I know having so many base pairs makes rebasing complicated, but you're in Bilateria, so shouldn't you at LEAST be better at using git head?",
+  "dither": false,
   "feed": false
 }

showbits-thermal-printer/src/documents/xkcd/main.typ

@@ -9,14 +9,18 @@
   #text(size: 32pt, data.title)
 ]
 
-// If the image is an odd number of pixels wide, we need to add an extra row of
-// pixels (in this case, on the right) to ensure that the image pixels fall on
-// screen pixels.
-#context {
-  let img = image("image.png")
-  let width = measure(img).width
-  let additional = 2pt * calc.fract(width.pt() / 2)
-  align(center, stack(dir: ltr, img, h(additional)))
+#if data.dither {
+  // If the image is an odd number of pixels wide, we need to add an extra row
+  // of pixels (in this case, on the right) to ensure that the image pixels fall
+  // on screen pixels.
+  context {
+    let img = image("image.png")
+    let width = measure(img).width
+    let additional = 2pt * calc.fract(width.pt() / 2)
+    align(center, stack(dir: ltr, img, h(additional)))
+  }
+} else {
+  image("image.png", width: lib.width)
 }
 
 #align(center, data.alt)

showbits-thermal-printer/src/documents/xkcd/mod.rs

@@ -24,12 +24,15 @@ struct Data {
     number: u32,
     title: String,
     alt: String,
+    dither: bool,
     feed: bool,
 }
 
 #[derive(Deserialize)]
 pub struct FormData {
     pub number: Option<u32>,
+    pub dither: Option<bool>,
+    pub bright: Option<bool>,
     pub feed: Option<bool>,
 }
 
@@ -46,20 +49,29 @@ pub async fn post(server: State<Server>, Form(form): Form<FormData>) -> somehow:
     let info = client.get(url).send().await?.json::<ComicInfo>().await?;
 
     let image_data = client.get(&info.img).send().await?.bytes().await?;
-    let image = image::load_from_memory(&image_data)?.into_rgba8();
-
-    let max_width = Some(384);
-    let max_height = Some(1024);
-    let image = super::image::dither(image, max_width, max_height, false, "stucki")
-        .map_err(somehow::Error)?;
+    let mut image = image::load_from_memory(&image_data)?.into_rgba8();
 
     let data = Data {
         number: info.num,
         title: info.title,
         alt: info.alt,
+        dither: form.dither.unwrap_or(true),
         feed: form.feed.unwrap_or(true),
     };
 
+    if data.dither {
+        let max_width = Some(384);
+        let max_height = Some(1024);
+        image = super::image::dither(
+            image,
+            max_width,
+            max_height,
+            form.bright.unwrap_or(false),
+            "stucki",
+        )
+        .map_err(somehow::Error)?;
+    }
+
     let mut bytes: Vec<u8> = Vec::new();
     image
         .write_to(&mut Cursor::new(&mut bytes), ImageFormat::Png)