feat: concurrently load & parse fonts

Cargo.toml

@@ -28,6 +28,7 @@ ttf-parser = { version = "0.20.0", default-features = false }
 unicode-linebreak = "0.1.5"
 unicode-script = "0.5.5"
 unicode-segmentation = "1.10.1"
+rayon = { version = "1", optional = true }
 
 [dependencies.unicode-bidi]
 version = "0.3.13"
@@ -35,7 +36,7 @@ default-features = false
 features = ["hardcoded-data"]
 
 [features]
-default = ["std", "swash", "fontconfig"]
+default = ["std", "swash", "fontconfig", "rayon"]
 fontconfig = ["fontdb/fontconfig", "std"]
 no_std = ["rustybuzz/libm", "hashbrown"]
 shape-run-cache = []
@@ -50,6 +51,7 @@ std = [
 vi = ["modit", "syntect", "cosmic_undo_2"]
 wasm-web = ["sys-locale?/js"]
 warn_on_missing_glyphs = []
+rayon = ["dep:rayon"]
 
 [[bench]]
 name = "layout"

src/font/mod.rs

@@ -158,3 +158,26 @@ impl Font {
         })
     }
 }
+
+#[cfg(test)]
+mod test{
+    #[test]
+    fn test_fonts_load_time(){
+        use crate::FontSystem;
+        use sys_locale::get_locale;
+
+        #[cfg(not(target_arch = "wasm32"))]
+        let now = std::time::Instant::now();
+
+        let mut db = fontdb::Database::new();
+        let locale = get_locale().unwrap();
+        db.load_system_fonts();
+        FontSystem::new_with_locale_and_db(locale, db);
+
+        #[cfg(not(target_arch = "wasm32"))]
+        println!(
+            "Fonts load time {}ms.",
+            now.elapsed().as_millis()
+        )
+    }
+}

src/font/system.rs

@@ -172,7 +172,7 @@ impl FontSystem {
             #[cfg(feature = "shape-run-cache")]
             shape_run_cache: crate::ShapeRunCache::default(),
         };
-
+        ret.cache_fonts(cloned_monospace_font_ids.clone());
         cloned_monospace_font_ids.into_iter().for_each(|id| {
             if let Some(font) = ret.get_font(id) {
                 font.scripts().iter().copied().for_each(|script| {
@@ -211,6 +211,45 @@ impl FontSystem {
     pub fn into_locale_and_db(self) -> (String, fontdb::Database) {
         (self.locale, self.db)
     }
+    /// Concurrently cache fonts by id list
+    pub fn cache_fonts(&mut self, mut ids: Vec<fontdb::ID>) {
+        #[cfg(feature = "rayon")]
+        use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
+        ids = ids
+            .into_iter()
+            .filter(|id| {
+                let contains = self.font_cache.contains_key(id);
+                #[cfg(feature = "std")]
+                unsafe {
+                    self.db.make_shared_face_data(*id);
+                }
+                !contains
+            })
+            .collect::<_>();
+
+        #[cfg(feature = "rayon")]
+        let fonts = ids.par_iter();
+        #[cfg(not(feature = "rayon"))]
+        let fonts = ids.iter();
+
+        fonts
+            .map(|id| match Font::new(&self.db, *id) {
+                Some(font) => Some(Arc::new(font)),
+                None => {
+                    log::warn!(
+                        "failed to load font '{}'",
+                        self.db.face(*id)?.post_script_name
+                    );
+                    None
+                }
+            })
+            .collect::<Vec<Option<Arc<Font>>>>()
+            .into_iter()
+            .flatten()
+            .for_each(|font| {
+                self.font_cache.insert(font.id, Some(font));
+            });
+    }
 
     /// Get a font by its ID.
     pub fn get_font(&mut self, id: fontdb::ID) -> Option<Arc<Font>> {