Add /typst

showbits-common/src/widgets/typst.rs

@@ -0,0 +1,219 @@
+use std::{fs, path::PathBuf, sync::OnceLock};
+
+use anyhow::anyhow;
+use comemo::Prehashed;
+use image::RgbaImage;
+use taffy::{
+    prelude::{AvailableSpace, Size},
+    Layout,
+};
+use typst::{
+    diag::{FileError, FileResult},
+    eval::Tracer,
+    foundations::{Bytes, Datetime},
+    layout::Abs,
+    syntax::{FileId, Source},
+    text::{Font, FontBook},
+    visualize::Color,
+    Library, World,
+};
+
+use crate::{View, Widget};
+
+// The logic for detecting and loading fonts was ripped straight from:
+// https://github.com/typst/typst/blob/69dcc89d84176838c293b2d59747cd65e28843ad/crates/typst-cli/src/fonts.rs
+// https://github.com/typst/typst/blob/69dcc89d84176838c293b2d59747cd65e28843ad/crates/typst-cli/src/world.rs#L193-L195
+
+struct FontSlot {
+    path: PathBuf,
+    index: u32,
+    font: OnceLock<Option<Font>>,
+}
+
+impl FontSlot {
+    pub fn get(&self) -> Option<Font> {
+        self.font
+            .get_or_init(|| {
+                let data = fs::read(&self.path).ok()?.into();
+                Font::new(data, self.index)
+            })
+            .clone()
+    }
+}
+
+struct FontLoader {
+    book: FontBook,
+    fonts: Vec<FontSlot>,
+}
+
+impl FontLoader {
+    fn new() -> Self {
+        Self {
+            book: FontBook::new(),
+            fonts: vec![],
+        }
+    }
+
+    fn load_embedded_fonts(&mut self) {
+        // https://github.com/typst/typst/blob/be12762d942e978ddf2e0ac5c34125264ab483b7/crates/typst-cli/src/fonts.rs#L107-L121
+        for font_file in typst_assets::fonts() {
+            let font_data = Bytes::from_static(font_file);
+            for (i, font) in Font::iter(font_data).enumerate() {
+                self.book.push(font.info().clone());
+                self.fonts.push(FontSlot {
+                    path: PathBuf::new(),
+                    index: i as u32,
+                    font: OnceLock::from(Some(font)),
+                });
+            }
+        }
+    }
+}
+
+struct DummyWorld {
+    library: Prehashed<Library>,
+    book: Prehashed<FontBook>,
+    main: Source,
+    fonts: Vec<FontSlot>,
+}
+
+impl DummyWorld {
+    fn new(main: String) -> Self {
+        let mut loader = FontLoader::new();
+        loader.load_embedded_fonts();
+
+        Self {
+            library: Prehashed::new(Library::builder().build()),
+            book: Prehashed::new(loader.book),
+            main: Source::detached(main),
+            fonts: loader.fonts,
+        }
+    }
+}
+
+impl World for DummyWorld {
+    fn library(&self) -> &Prehashed<Library> {
+        &self.library
+    }
+
+    fn book(&self) -> &Prehashed<FontBook> {
+        &self.book
+    }
+
+    fn main(&self) -> Source {
+        self.main.clone()
+    }
+
+    fn source(&self, _id: FileId) -> FileResult<Source> {
+        Err(FileError::AccessDenied)
+    }
+
+    fn file(&self, _id: FileId) -> FileResult<Bytes> {
+        Err(FileError::AccessDenied)
+    }
+
+    fn font(&self, index: usize) -> Option<Font> {
+        self.fonts[index].get()
+    }
+
+    fn today(&self, _offset: Option<i64>) -> Option<Datetime> {
+        None
+    }
+}
+
+const SCALE: f32 = 3.0;
+
+pub struct Typst {
+    code: String,
+}
+
+impl Typst {
+    pub fn new(code: String) -> Self {
+        Self { code }
+    }
+
+    fn render(&self, width: Option<f32>, height: Option<f32>) -> Result<RgbaImage, Vec<String>> {
+        let width = match width {
+            Some(width) => format!("{}pt", width / SCALE),
+            None => "auto".to_string(),
+        };
+
+        let height = match height {
+            Some(height) => format!("{}pt", height / SCALE),
+            None => "auto".to_string(),
+        };
+
+        let mut source = String::new();
+        source.push_str(&format!("#set page(width: {width}, height: {height})\n"));
+        source.push_str("#set page(margin: (left: 0mm, right: 0mm, top: 1mm, bottom: 2mm))\n");
+        source.push_str(&self.code);
+
+        let world = DummyWorld::new(source);
+        let mut tracer = Tracer::new();
+
+        let document = typst::compile(&world, &mut tracer).map_err(|errs| {
+            errs.into_iter()
+                .map(|sd| sd.message.to_string())
+                .collect::<Vec<_>>()
+        })?;
+
+        let pixmap =
+            typst_render::render_merged(&document, SCALE, Color::WHITE, Abs::zero(), Color::WHITE);
+
+        let buffer = RgbaImage::from_raw(pixmap.width(), pixmap.height(), pixmap.take()).unwrap();
+
+        Ok(buffer)
+    }
+}
+
+impl<C> Widget<C> for Typst {
+    fn size(
+        &mut self,
+        _ctx: &mut C,
+        known: Size<Option<f32>>,
+        available: Size<AvailableSpace>,
+    ) -> Size<f32> {
+        let width = known.width.or(match available.width {
+            AvailableSpace::Definite(width) => Some(width),
+            AvailableSpace::MinContent => None, // auto
+            AvailableSpace::MaxContent => Some(4096.0),
+        });
+
+        let height = known.height.or(match available.height {
+            AvailableSpace::Definite(width) => Some(width),
+            AvailableSpace::MinContent | AvailableSpace::MaxContent => None, // auto
+        });
+
+        let Ok(buffer) = self.render(width, height) else {
+            return Size {
+                width: width.unwrap_or(0.0),
+                height: height.unwrap_or(0.0),
+            };
+        };
+
+        // Round up so we definitely have enough space.
+        // let width = (buffer.width() as f32 / SCALE).ceil() * SCALE + 1.0;
+        // let height = (buffer.height() as f32 / SCALE).ceil() * SCALE + 1.0;
+        let width = (buffer.width() as f32).ceil() + 1.0;
+        let height = (buffer.height() as f32).ceil() + 1.0;
+
+        Size { width, height }
+    }
+
+    fn draw_below(
+        &mut self,
+        _ctx: &mut C,
+        view: &mut View<'_>,
+        _layout: &Layout,
+    ) -> anyhow::Result<()> {
+        let size = view.size();
+
+        let buffer = self
+            .render(Some(size.x as f32), Some(size.y as f32))
+            .map_err(|errs| anyhow!("{}", errs.join("\n")))?;
+
+        view.image(&buffer);
+
+        Ok(())
+    }
+}