WPT: reuse FontContext to avoid reloading system fonts

Takes runtime for css-flexbox from 12s -> 8s

apps/readme/src/main.rs

@@ -44,7 +44,7 @@ fn main() {
         Arc::clone(&net_callback) as SharedCallback<Resource>,
     ));
 
-    let document = HtmlDocument::from_html(&html, Some(base_url), stylesheets, net_provider);
+    let document = HtmlDocument::from_html(&html, Some(base_url), stylesheets, net_provider, None);
     dioxus_native::launch_with_document(document, rt, Some(net_callback));
 }
 

apps/wpt/Cargo.toml

@@ -10,6 +10,7 @@ blitz-net = { path = "../../packages/blitz-net" }
 blitz-traits = { path = "../../packages/blitz-traits" }
 blitz-renderer-vello = { path = "../../packages/blitz-renderer-vello" }
 dioxus-native = { path = "../../packages/dioxus-native", features = ["tracing"] }
+parley = { workspace = true }
 tokio = { workspace = true }
 png = { version = "0.17" }
 glob = {version = "0.3.1"}

apps/wpt/src/main.rs

@@ -3,6 +3,7 @@ use blitz_dom::{HtmlDocument, Viewport};
 use blitz_net::{MpscCallback, Provider};
 use blitz_renderer_vello::VelloImageRenderer;
 use blitz_traits::net::SharedProvider;
+use parley::FontContext;
 use reqwest::Url;
 use tower_http::services::ServeDir;
 
@@ -98,6 +99,13 @@ fn setup_blitz() -> BlitzContext {
     }
 }
 
+fn clone_font_ctx(ctx: &FontContext) -> FontContext {
+    FontContext {
+        collection: ctx.collection.clone(),
+        source_cache: ctx.source_cache.clone(),
+    }
+}
+
 fn main() {
     env_logger::init();
     let rt = tokio::runtime::Builder::new_current_thread()
@@ -141,13 +149,16 @@ fn main() {
 
     let num = AtomicU32::new(0);
 
+    let base_font_context = parley::FontContext::default();
+
     test_paths.into_par_iter().for_each_init(
         || {
             let renderer = rt.block_on(VelloImageRenderer::new(WIDTH, HEIGHT, SCALE));
+            let font_ctx = clone_font_ctx(&base_font_context);
             let test_buffer = Vec::with_capacity((WIDTH * HEIGHT * 4) as usize);
             let ref_buffer = Vec::with_capacity((WIDTH * HEIGHT * 4) as usize);
             let guard = rt.enter();
-            (renderer, test_buffer, ref_buffer, guard)
+            (renderer, font_ctx, test_buffer, ref_buffer, guard)
         },
         |state, path| {
             let num = num.fetch_add(1, Ordering::SeqCst) + 1;
@@ -162,13 +173,15 @@ fn main() {
             let url = base_url.join(relative_path.as_str()).unwrap();
 
             let renderer = &mut state.0;
-            let test_buffer = &mut state.1;
-            let ref_buffer = &mut state.2;
+            let font_ctx = &state.1;
+            let test_buffer = &mut state.2;
+            let ref_buffer = &mut state.3;
 
             let result = catch_unwind(AssertUnwindSafe(|| {
                 let mut blitz_context = setup_blitz();
                 let result = rt.block_on(process_test_file(
                     renderer,
+                    font_ctx,
                     test_buffer,
                     ref_buffer,
                     &url,
@@ -231,6 +244,7 @@ async fn serve(app: Router, port: u16) {
 #[allow(clippy::too_many_arguments)]
 async fn process_test_file(
     renderer: &mut VelloImageRenderer,
+    font_ctx: &FontContext,
     test_buffer: &mut Vec<u8>,
     ref_buffer: &mut Vec<u8>,
     path: &Url,
@@ -255,6 +269,7 @@ async fn process_test_file(
     if let Some(reference) = reference {
         process_test_file_with_ref(
             renderer,
+            font_ctx,
             test_buffer,
             ref_buffer,
             path,
@@ -274,6 +289,7 @@ async fn process_test_file(
 #[allow(clippy::too_many_arguments)]
 async fn process_test_file_with_ref(
     renderer: &mut VelloImageRenderer,
+    font_ctx: &FontContext,
     test_buffer: &mut Vec<u8>,
     ref_buffer: &mut Vec<u8>,
     test_url: &Url,
@@ -306,6 +322,7 @@ async fn process_test_file_with_ref(
     render_html_to_buffer(
         blitz_context,
         renderer,
+        font_ctx,
         test_file_contents,
         test_url,
         test_buffer,
@@ -317,6 +334,7 @@ async fn process_test_file_with_ref(
     render_html_to_buffer(
         blitz_context,
         renderer,
+        font_ctx,
         &reference_file_contents,
         &ref_url,
         ref_buffer,
@@ -345,6 +363,7 @@ async fn process_test_file_with_ref(
 async fn render_html_to_buffer(
     blitz_context: &mut BlitzContext,
     renderer: &mut VelloImageRenderer,
+    font_ctx: &FontContext,
     html: &str,
     base_url: &Url,
     buf: &mut Vec<u8>,
@@ -355,6 +374,7 @@ async fn render_html_to_buffer(
         Some(base_url.to_string()),
         Vec::new(),
         Arc::clone(&blitz_context.net) as SharedProvider<Resource>,
+        Some(clone_font_ctx(font_ctx)),
     );
 
     document

examples/screenshot.rs

@@ -72,6 +72,7 @@ async fn main() {
         Some(url_string.clone()),
         Vec::new(),
         Arc::clone(&net) as SharedProvider<Resource>,
+        None,
     );
 
     timer.time("Parsed document");

packages/blitz-dom/src/document.rs

@@ -3,7 +3,7 @@ use crate::node::{ImageData, NodeSpecificData, TextBrush};
 use crate::{ElementNodeData, Node, NodeData, TextNodeData, Viewport};
 use app_units::Au;
 use html5ever::local_name;
-use parley::PlainEditorOp;
+use parley::{FontContext, PlainEditorOp};
 use peniko::kurbo;
 use string_cache::Atom;
 use style::attr::{AttrIdentifier, AttrValue};
@@ -382,6 +382,10 @@ impl DocumentLike for Document {
 
 impl Document {
     pub fn new(viewport: Viewport) -> Self {
+        Self::with_font_ctx(viewport, parley::FontContext::default())
+    }
+
+    pub fn with_font_ctx(viewport: Viewport, mut font_ctx: FontContext) -> Self {
         let device = viewport.make_device();
         let stylist = Stylist::new(device, QuirksMode::NoQuirks);
         let snapshots = SnapshotMap::new();
@@ -395,7 +399,9 @@ impl Document {
         style_config::set_bool("layout.legacy_layout", true);
         style_config::set_bool("layout.columns.enabled", true);
 
-        let font_ctx = Self::create_font_context();
+        font_ctx
+            .collection
+            .register_fonts(include_bytes!("moz-bullet-font.otf").to_vec());
 
         let mut doc = Self {
             guard,
@@ -423,13 +429,6 @@ impl Document {
         doc
     }
 
-    fn create_font_context() -> parley::FontContext {
-        let mut ctx = parley::FontContext::default();
-        ctx.collection
-            .register_fonts(include_bytes!("moz-bullet-font.otf").to_vec());
-        ctx
-    }
-
     /// Set base url for resolving linked resources (stylesheets, images, fonts, etc)
     pub fn set_base_url(&mut self, url: &str) {
         self.base_url = Some(Url::parse(url).unwrap());

packages/blitz-dom/src/html_document.rs

@@ -4,6 +4,7 @@ use crate::{Document, DocumentHtmlParser, DocumentLike, Viewport};
 use crate::net::Resource;
 use crate::DEFAULT_CSS;
 use blitz_traits::net::SharedProvider;
+use parley::FontContext;
 
 pub struct HtmlDocument {
     inner: Document,
@@ -38,10 +39,14 @@ impl HtmlDocument {
         base_url: Option<String>,
         stylesheets: Vec<String>,
         net_provider: SharedProvider<Resource>,
+        font_ctx: Option<FontContext>,
     ) -> Self {
         // Spin up the virtualdom and include the default stylesheet
         let viewport = Viewport::new(0, 0, 1.0);
-        let mut dom = Document::new(viewport);
+        let mut dom = match font_ctx {
+            Some(font_ctx) => Document::with_font_ctx(viewport, font_ctx),
+            None => Document::new(viewport),
+        };
 
         // Set base url if configured
         if let Some(url) = &base_url {

packages/dioxus-native/src/lib.rs

@@ -127,7 +127,7 @@ pub fn launch_static_html_cfg(html: &str, cfg: Config) {
         Arc::clone(&net_callback) as SharedCallback<Resource>,
     ));
 
-    let document = HtmlDocument::from_html(html, cfg.base_url, cfg.stylesheets, net_provider);
+    let document = HtmlDocument::from_html(html, cfg.base_url, cfg.stylesheets, net_provider, None);
     launch_with_document(document, rt, Some(net_callback));
 }