Move Parley behind a compile-time text backend boundary

.github/workflows/ci.yml

@@ -55,6 +55,24 @@ jobs:
       - run: sudo apt-get update && sudo apt-get install -y libfontconfig1-dev
       - run: cargo build --workspace
 
+  # The text backend feature: Parley, on by default, is required: without it
+  # blitz-dom must fail to compile.
+  check-text-backends:
+    name: "Check text backend features"
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: sudo apt-get update && sudo apt-get install -y libfontconfig1-dev
+      - name: Parley (default)
+        run: cargo check -p blitz-dom -p blitz-paint -p blitz -p wpt
+      - name: No backend fails to compile
+        run: |
+          if cargo check -p blitz-dom --no-default-features --features svg 2> neither.log; then
+            echo "blitz-dom built without a text backend"; exit 1
+          fi
+          grep -q "Enable the \`parley\` feature" neither.log
+
   # wasm_hello is a standalone workspace; seven_guis and todomvc are workspace
   # members with a [lib] crate-type = ["cdylib"] target for wasm.
   build-wasm-examples:
@@ -70,9 +88,9 @@ jobs:
         run: cargo build --target wasm32-unknown-unknown
         working-directory: examples/wasm_hello
       - name: Build seven_guis (wasm)
-        run: cargo build -p seven_guis --lib --target wasm32-unknown-unknown --no-default-features --features hybrid
+        run: cargo build -p seven_guis --lib --target wasm32-unknown-unknown --no-default-features --features hybrid,parley
       - name: Build todomvc (wasm)
-        run: cargo build -p todomvc --lib --target wasm32-unknown-unknown --no-default-features --features hybrid
+        run: cargo build -p todomvc --lib --target wasm32-unknown-unknown --no-default-features --features hybrid,parley
 
   fmt:
     name: Rustfmt
@@ -96,7 +114,7 @@ jobs:
           components: clippy
       - run: sudo apt-get update && sudo apt-get install -y libfontconfig1-dev
       - run: cargo clippy --workspace -- -D warnings
-      - run: cargo clippy -p blitz-dom --no-default-features --features svg,woff,accessibility,system-fonts,file-input,custom-widget --all-targets -- -D warnings
+      - run: cargo clippy -p blitz-dom --no-default-features --features parley,svg,woff,accessibility,system-fonts,file-input,custom-widget --all-targets -- -D warnings
 
   ci-scripts:
     name: "Test CI scripts"

Cargo.toml

@@ -55,7 +55,7 @@ dioxus-native-dom = { version = "0.7.0", path = "./packages/dioxus-native-dom",
 debug_timer = { version = "0.1.2", path = "./packages/debug_timer" }
 accesskit_xplat = { version = "0.2", path = "./packages/accesskit_xplat", default-features = false }
 browser-persistence = { path = "./apps/browser/persistence" }
-blitz-test-harness = { path = "./packages/blitz-test-harness" }
+blitz-test-harness = { path = "./packages/blitz-test-harness", default-features = false }
 
 # Servo dependencies
 style = { version = "0.22.0", package = "stylo" }
@@ -257,13 +257,16 @@ publish = false
 log-times = ["log-frame-times", "log-phase-times"]
 log-frame-times = ["dioxus-native/log-frame-times"]
 log-phase-times = ["dioxus-native/log-phase-times"]
+# The text backend, which is Parley: on by default, and required.
+default = ["parley"]
+parley = ["blitz-dom/parley", "blitz-paint/parley", "dioxus-native/parley"]
 
 [dev-dependencies]
 anyrender = { workspace = true }
 anyrender_vello = { workspace = true }
 anyrender_vello_cpu = { workspace = true, features = ["multithreading"] }
 anyrender_vello_hybrid = { workspace = true }
-blitz-dom = { workspace = true, features = ["default"] }
+blitz-dom = { workspace = true, features = ["svg", "woff", "accessibility", "system-fonts", "file-input", "custom-widget", "text-transform-icu"] }
 blitz-html = { workspace = true }
 blitz-traits = { workspace = true }
 blitz-paint = { workspace = true }

apps/browser/Cargo.toml

@@ -10,7 +10,7 @@ name = "blitz"
 path = "src/main.rs"
 
 [features]
-default = ["hybrid", "cookies", "cache", "screenshot", "apple-font-embolden", "scrollbars"]
+default = ["hybrid", "cookies", "cache", "screenshot", "apple-font-embolden", "scrollbars", "parley"]
 android-defaults = ["skia", "cookies"]
 
 screenshot = ["dep:anyrender_vello_cpu", "dep:blitz-paint", "dep:png", "dep:peniko", "dep:rfd"]
@@ -41,6 +41,8 @@ mimalloc = ["dep:mimalloc"]
 font-embolden = ["dioxus-native/font-embolden"]
 apple-font-embolden = ["dioxus-native/apple-font-embolden"]
 writing-mode = ["blitz-dom/writing-mode", "dioxus-native/writing-mode"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley", "blitz-dom/parley", "blitz-html/parley", "blitz-paint?/parley", "blitz-vibey-script?/parley"]
 
 [dependencies]
 dioxus-native = { workspace = true, features = [

apps/browser/src/document_loader.rs

@@ -1,13 +1,13 @@
 use std::sync::{Arc, Mutex};
 
+use blitz_dom::text::TextFonts as _;
 use blitz_dom::{DocumentConfig, FontContext};
 use blitz_html::{HtmlDocument, HtmlProvider};
 use blitz_traits::{
     net::{AbortController, AbortSignal, Request, Url},
     shell::ShellProvider,
 };
 use dioxus_native::{SubDocumentAttr, prelude::*};
-use linebender_resource_handle::Blob;
 
 use crate::StdNetProvider;
 use crate::favicon::favicon_candidate;
@@ -67,9 +67,7 @@ pub fn make_doc_config(
 impl DocumentLoader {
     pub fn new(net_provider: Arc<StdNetProvider>, history: SyncStore<History>) -> Self {
         let mut font_ctx = FontContext::default();
-        font_ctx
-            .collection
-            .register_fonts(Blob::new(Arc::new(blitz_dom::BULLET_FONT) as _), None);
+        font_ctx.add_fonts(blitz_dom::BULLET_FONT);
 
         Self {
             font_ctx,

apps/readme/Cargo.toml

@@ -10,7 +10,9 @@ repository.workspace = true
 publish = true
 
 [features]
-default = ["hybrid", "comrak", "floats", "scrollbars"]
+default = ["hybrid", "comrak", "floats", "scrollbars", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["blitz-dom/parley", "blitz-html/parley", "blitz-paint/parley", "blitz-shell/parley"]
 
 # Renderers
 gpu = ["dep:anyrender_vello"]
@@ -43,11 +45,11 @@ tracing = ["dep:tracing-subscriber", "blitz-shell/tracing", "blitz-net/tracing",
 
 [dependencies]
 blitz-traits = { workspace = true }
-blitz-dom = { workspace = true, features = ["default", "parallel-construct"] }
+blitz-dom = { workspace = true, features = ["svg", "woff", "accessibility", "system-fonts", "file-input", "custom-widget", "text-transform-icu", "parallel-construct"] }
 blitz-html = { workspace = true }
-blitz-paint = { workspace = true, features = ["default"] }
+blitz-paint = { workspace = true, features = ["svg"] }
 blitz-net = { workspace = true, features = ["cookies"] }
-blitz-shell = { workspace = true, features = ["default"] }
+blitz-shell = { workspace = true, features = ["accessibility", "clipboard", "file-dialog"] }
 anyrender_vello = { workspace = true, optional = true }
 anyrender_skia = { workspace = true, optional = true }
 anyrender_vello_cpu = { workspace = true, features = ["multithreading"], optional = true }

examples/counter/Cargo.toml

@@ -9,7 +9,9 @@ publish = false
 crate-type = ["cdylib"]
 
 [features]
-default = ["hybrid"]
+default = ["hybrid", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley", "blitz-dom/parley", "blitz-paint/parley"]
 system-fonts = ["blitz-dom/system-fonts"]
 vello = ["dioxus-native/vello"]
 cpu = ["cpu-pixels"]

examples/seven_guis/Cargo.toml

@@ -13,7 +13,9 @@ path = "src/main.rs"
 crate-type = ["cdylib", "rlib"]
 
 [features]
-default = ["hybrid"]
+default = ["hybrid", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley"]
 vello = ["dioxus-native/vello"]
 hybrid = ["dioxus-native/vello-hybrid"]
 skia = ["dioxus-native/skia"]

examples/todomvc/Cargo.toml

@@ -13,7 +13,9 @@ path = "src/main.rs"
 crate-type = ["cdylib"]
 
 [features]
-default = ["hybrid"]
+default = ["hybrid", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley"]
 vello = ["dioxus-native/vello"]
 hybrid = ["dioxus-native/vello-hybrid"]
 skia = ["dioxus-native/skia"]

examples/transparent/Cargo.toml

@@ -6,7 +6,9 @@ license.workspace = true
 publish = false
 
 [features]
-default = ["hybrid"]
+default = ["hybrid", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley", "blitz-dom/parley", "blitz-paint/parley"]
 system-fonts = ["blitz-dom/system-fonts"]
 vello = ["dioxus-native/vello"]
 cpu = ["cpu-pixels"]

examples/wasm_hello/Cargo.toml

@@ -10,7 +10,8 @@ crate-type = ["cdylib"]
 
 [dependencies]
 anyrender_vello_hybrid = { workspace = true, features = ["webgl"] }
-blitz-dom = { workspace = true, features = ["woff"] }
+# This example builds Parley's font context itself.
+blitz-dom = { workspace = true, features = ["woff", "parley"] }
 blitz-html = { workspace = true }
 blitz-shell = { workspace = true, default-features = false, features = ["tracing"]}
 

examples/wgpu_texture/Cargo.toml

@@ -9,7 +9,9 @@ license = "MIT"
 publish = false
 
 [features]
-default = ["vello-hybrid"]
+default = ["vello-hybrid", "parley"]
+# The text backend, which is Parley: on by default, and required.
+parley = ["dioxus-native/parley", "blitz-dom/parley", "blitz-paint/parley", "blitz-html/parley", "blitz-shell/parley"]
 vello = ["dep:anyrender_vello", "dioxus-native/vello"]
 vello-hybrid = ["dep:anyrender_vello_hybrid", "dioxus-native/vello-hybrid"]
 

packages/blitz-dom/Cargo.toml

@@ -18,17 +18,21 @@ default = [
     "system-fonts",
     "file-input",
     "custom-widget",
-    "text-transform-icu"
+    "text-transform-icu",
+    "parley",
 ]
+# The text backend that lays out, edits and reads back text: Parley. It must be
+# enabled.
+parley = ["dep:parley"]
 custom-widget = ["dep:anyrender", "accessibility"]
 tracing = ["dep:tracing"]
 svg = ["dep:usvg", "dep:svgtypes"]
 # WOFF decoding (using the "wuff" crate which is pure Rust)
 woff = ["dep:wuff"]
 accessibility = ["accesskit"]
-system-fonts = ["parley/system"]
+system-fonts = ["parley?/system"]
 # complex-scripts: enable dictionary-based line-breaking
-complex-scripts = ["parley/complex-scripts"]
+complex-scripts = ["parley?/complex-scripts"]
 # text-transform-icu: language-aware, Unicode-complete case mapping for `text-transform`
 # (otherwise falls back to the standard library's case mapping)
 text-transform-icu = ["dep:icu_casemap", "dep:writeable"]
@@ -69,7 +73,8 @@ anyrender = { workspace = true, optional = true }
 
 # Linebender/Fontations dependencies
 accesskit = { workspace = true, optional = true }
-parley = { workspace = true }
+# blitz-paint casts Parley's glyph coordinates with bytemuck.
+parley = { workspace = true, optional = true, features = ["bytemuck"] }
 skrifa = { workspace = true }
 linebender_resource_handle = { workspace = true }
 color = { workspace = true }

packages/blitz-dom/build.rs

@@ -0,0 +1,8 @@
+//! Reads the text backend feature into the `text_parley` cfg, which the code reads in its place.
+
+fn main() {
+    println!("cargo::rustc-check-cfg=cfg(text_parley)");
+    if std::env::var_os("CARGO_FEATURE_PARLEY").is_some() {
+        println!("cargo::rustc-cfg=text_parley");
+    }
+}

packages/blitz-dom/src/config.rs

@@ -1,10 +1,10 @@
 use crate::HtmlParserProvider;
+use crate::text::FontContext;
 use blitz_traits::{
     navigation::NavigationProvider,
     net::{AbortSignal, NetProvider},
     shell::{ShellProvider, Viewport},
 };
-use parley::FontContext;
 use std::sync::Arc;
 use style::media_queries::MediaType;
 
@@ -45,7 +45,10 @@ pub struct DocumentConfig {
     pub shell_provider: Option<Arc<dyn ShellProvider>>,
     /// HTML parser provider. Used to parse HTML for setInnerHTML
     pub html_parser_provider: Option<Arc<dyn HtmlParserProvider>>,
-    /// Parley `FontContext`
+    /// The fonts the document lays out text with. Defaults to the platform's fonts, where Blitz
+    /// is built to read them (`system-fonts`), and Blitz's bullet font. Clones share loaded
+    /// fonts, so hand a clone of one to every document rather than listing the platform's fonts
+    /// for each.
     pub font_ctx: Option<FontContext>,
     /// The CSS media type used to evaluate `@media` rules.
     /// Defaults to [`MediaType::screen`].

packages/blitz-dom/src/debug.rs

@@ -1,8 +1,8 @@
 use blitz_traits::node_id::NodeId;
-use parley::layout::PositionedLayoutItem;
 
 use crate::BaseDocument;
 use crate::layout::TaffyDebugTree;
+use crate::text::InlineText as _;
 
 impl BaseDocument {
     pub fn print_taffy_tree(&self) {
@@ -42,48 +42,7 @@ impl BaseDocument {
                 .as_ref()
                 .unwrap();
 
-            println!(
-                "Size: {}x{}",
-                inline_layout.layout.width(),
-                inline_layout.layout.height()
-            );
-            println!("Text content: {:?}", inline_layout.text);
-            println!("Inline Boxes:");
-            for ibox in inline_layout.layout.inline_boxes() {
-                print!("(id: {}) ", ibox.id);
-            }
-            println!();
-            println!("Lines:");
-            for (i, line) in inline_layout.layout.lines().enumerate() {
-                let metrics = line.metrics();
-                let x = metrics.inline_min_coord;
-                let y = metrics.block_min_coord;
-                let w = metrics.inline_max_coord - metrics.inline_min_coord;
-                let h = metrics.block_max_coord - metrics.block_min_coord;
-                println!("Line {i}: x:{x} y:{y} width:{w} height:{h}");
-                for item in line.items() {
-                    print!("  ");
-                    match item {
-                        PositionedLayoutItem::GlyphRun(run) => {
-                            print!(
-                                "RUN (x: {}, w: {}) ",
-                                run.offset().round(),
-                                run.run().advance()
-                            )
-                        }
-                        PositionedLayoutItem::InlineBox(ibox) => print!(
-                            "BOX {:?} (id: {} x: {} y: {} w: {}, h: {})",
-                            ibox.kind,
-                            ibox.id,
-                            ibox.x.round(),
-                            ibox.y.round(),
-                            ibox.width.round(),
-                            ibox.height.round()
-                        ),
-                    }
-                    println!();
-                }
-            }
+            inline_layout.debug_print();
         }
 
         let layout = node.final_layout();