Typstify /cells endpoint

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

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+{
+  "feed": true
+}

showbits-thermal-printer/src/documents/cells/lib

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+../lib

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

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+#import "lib/main.typ" as lib;
+#show: it => lib.init(it)
+
+#let data = json("data.json")
+
+#image("image.png")
+
+#if data.feed {
+  lib.feed
+}

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

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+use std::io::Cursor;
+
+use anyhow::Context;
+use axum::{Form, extract::State};
+use image::{ImageFormat, Rgba, RgbaImage, imageops};
+use serde::{Deserialize, Serialize};
+
+use crate::{
+    drawer::{Command, NewTypstDrawing},
+    printer::Printer,
+    server::{Server, somehow},
+};
+
+const BLACK: Rgba<u8> = Rgba([0, 0, 0, 255]);
+const WHITE: Rgba<u8> = Rgba([255, 255, 255, 255]);
+
+fn b2c(bool: bool) -> Rgba<u8> {
+    match bool {
+        true => BLACK,
+        false => WHITE,
+    }
+}
+
+fn c2b(color: Rgba<u8>) -> bool {
+    color == BLACK
+}
+
+fn neighbors_at(image: &RgbaImage, x: u32, y: u32) -> [bool; 3] {
+    let left = x
+        .checked_sub(1)
+        .map(|x| *image.get_pixel(x, y))
+        .unwrap_or(WHITE);
+
+    let mid = *image.get_pixel(x, y);
+
+    let right = image.get_pixel_checked(x + 1, y).copied().unwrap_or(WHITE);
+
+    [c2b(left), c2b(mid), c2b(right)]
+}
+
+fn apply_rule(rule: u8, neighbors: [bool; 3]) -> bool {
+    let [left, mid, right] = neighbors.map(|n| n as u8);
+    let index = (left << 2) | (mid << 1) | right;
+    rule & (1 << index) != 0
+}
+
+#[derive(Serialize)]
+struct Data {
+    feed: bool,
+}
+
+#[derive(Deserialize)]
+pub struct FormData {
+    pub rule: Option<u8>,
+    pub rows: Option<u32>,
+    pub scale: Option<u32>,
+    pub feed: Option<bool>,
+}
+
+pub async fn post(server: State<Server>, Form(form): Form<FormData>) -> somehow::Result<()> {
+    let data = Data {
+        feed: form.feed.unwrap_or(true),
+    };
+
+    let rule = form.rule.unwrap_or_else(rand::random);
+    let scale = form.scale.unwrap_or(4).clamp(1, 16);
+    let rows = form.rows.unwrap_or(128 * 4 / scale).clamp(1, 1024 / scale);
+    let cols = Printer::WIDTH / scale;
+
+    let mut image: image::ImageBuffer<Rgba<u8>, Vec<u8>> = RgbaImage::new(cols, rows);
+
+    // Initialize first line randomly
+    for x in 0..image.width() {
+        image.put_pixel(x, 0, b2c(rand::random()));
+    }
+
+    // Calculate next rows
+    for y in 1..image.height() {
+        for x in 0..image.width() {
+            let neighbors = neighbors_at(&image, x, y - 1);
+            let state = apply_rule(rule, neighbors);
+            image.put_pixel(x, y, b2c(state));
+        }
+    }
+
+    let image = imageops::resize(
+        &image,
+        image.width() * scale,
+        image.height() * scale,
+        imageops::Nearest,
+    );
+
+    let mut bytes: Vec<u8> = Vec::new();
+    image
+        .write_to(&mut Cursor::new(&mut bytes), ImageFormat::Png)
+        .context("failed to encode image as png")
+        .map_err(somehow::Error)?;
+
+    let typst = super::typst_with_lib()
+        .with_json("/data.json", &data)
+        .with_file("/image.png", bytes)
+        .with_main_file(include_str!("main.typ"));
+
+    let _ = server
+        .tx
+        .send(Command::draw(NewTypstDrawing::new(typst)))
+        .await;
+
+    Ok(())
+}