Use WebRender with fontations backend

Signed-off-by: Nico Burns <nico@nicoburns.com>
Fix .ttc files on macos
2026-04-25 17:15:48 +02:00 · 2025-08-17 19:24:38 +01:00 · 2025-08-17 14:49:15 +01:00 · 2025-08-16 23:40:39 +01:00 · 2025-08-16 15:55:59 +01:00 · 2025-08-16 14:23:44 +01:00
16 changed files with 1043 additions and 802 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1088,7 +1088,7 @@ dependencies = [
 "tracing",
 "unicode-script",
 "vello",
- "vello_cpu",
+ "vello_cpu 0.0.1 (git+https://github.com/linebender/vello?rev=b0e2e598ac62c7b3d04d8660e7b1b7659b596970)",
 "webrender_api",
 ]

@@ -2400,7 +2400,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "778e2ac28f6c47af28e4907f13ffd1e1ddbd400980a9abd7c8df189bf578a5ad"
 dependencies = [
 "libc",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -2586,6 +2586,16 @@ dependencies = [
 "bytemuck",
 ]

+[[package]]
+name = "fontconfig-cache-parser"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a7f8afb20c8069fd676d27b214559a337cc619a605d25a87baa90b49a06f3b18"
+dependencies = [
+ "bytemuck",
+ "thiserror 1.0.69",
+]
+
 [[package]]
 name = "fontconfig-parser"
 version = "0.5.8"
@@ -2609,6 +2619,29 @@ dependencies = [
 "ttf-parser",
 ]

+[[package]]
+name = "fontique"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "39f97079e1293b8c1e9fb03a2875d328bd2ee8f3b95ce62959c0acc04049c708"
+dependencies = [
+ "bytemuck",
+ "fontconfig-cache-parser",
+ "hashbrown",
+ "icu_locid",
+ "memmap2",
+ "objc2 0.6.1",
+ "objc2-core-foundation",
+ "objc2-core-text",
+ "objc2-foundation 0.3.1",
+ "peniko",
+ "read-fonts 0.29.3",
+ "roxmltree",
+ "smallvec",
+ "windows 0.58.0",
+ "windows-core 0.58.0",
+]
+
 [[package]]
 name = "fonts"
 version = "0.0.1"
@@ -2629,6 +2662,7 @@ dependencies = [
 "fontsan",
 "freetype-sys",
 "harfbuzz-sys",
+ "harfrust",
 "ipc-channel",
 "itertools 0.14.0",
 "libc",
@@ -2640,7 +2674,7 @@ dependencies = [
 "parking_lot",
 "profile_traits",
 "range",
- "read-fonts",
+ "read-fonts 0.31.3",
 "serde",
 "servo-tracing",
 "servo_allocator",
@@ -2648,7 +2682,7 @@ dependencies = [
 "servo_config",
 "servo_malloc_size_of",
 "servo_url",
- "skrifa",
+ "skrifa 0.33.2",
 "smallvec",
 "stylo",
 "stylo_atoms",
@@ -3048,7 +3082,7 @@ dependencies = [
 "gobject-sys",
 "libc",
 "system-deps",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -3602,12 +3636,27 @@ dependencies = [
 "winapi",
 ]

+[[package]]
+name = "harfrust"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dcd79170b62101f61285314e749ea0ccad616f8779d99571c6380a86d690ab9a"
+dependencies = [
+ "bitflags 2.9.1",
+ "bytemuck",
+ "core_maths",
+ "read-fonts 0.31.3",
+ "smallvec",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.15.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9229cfe53dfd69f0609a49f65461bd93001ea1ef889cd5529dd176593f5338a1"
 dependencies = [
+ "allocator-api2",
+ "equivalent",
 "foldhash",
 "serde",
 ]
@@ -4553,7 +4602,7 @@ checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
 dependencies = [
 "hermit-abi",
 "libc",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -4857,7 +4906,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "07033963ba89ebaf1584d767badaa2e8fcec21aedea6b8c0346d487d49c28667"
 dependencies = [
 "cfg-if",
- "windows-targets 0.52.6",
+ "windows-targets 0.48.5",
 ]

 [[package]]
@@ -5825,6 +5874,16 @@ dependencies = [
 "objc2-foundation 0.2.2",
 ]

+[[package]]
+name = "objc2-core-text"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ba833d4a1cb1aac330f8c973fd92b6ff1858e4aef5cdd00a255eefb28022fb5"
+dependencies = [
+ "bitflags 2.9.1",
+ "objc2-core-foundation",
+]
+
 [[package]]
 name = "objc2-encode"
 version = "4.1.0"
@@ -6239,7 +6298,6 @@ dependencies = [
 [[package]]
 name = "peek-poke"
 version = "0.3.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "euclid",
 "peek-poke-derive",
@@ -6248,7 +6306,6 @@ dependencies = [
 [[package]]
 name = "peek-poke-derive"
 version = "0.3.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "proc-macro2",
 "quote",
@@ -6832,6 +6889,17 @@ dependencies = [
 "font-types",
 ]

+[[package]]
+name = "read-fonts"
+version = "0.31.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b8250b8f09ed4b9ba9271e06f10e7b1f03e8f8e3619e2368a991ecb25efa204"
+dependencies = [
+ "bytemuck",
+ "core_maths",
+ "font-types",
+]
+
 [[package]]
 name = "redox_syscall"
 version = "0.4.1"
@@ -7016,7 +7084,7 @@ dependencies = [
 "errno",
 "libc",
 "linux-raw-sys 0.4.15",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -7029,7 +7097,7 @@ dependencies = [
 "errno",
 "libc",
 "linux-raw-sys 0.9.4",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -7902,7 +7970,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dbeb4ca4399663735553a09dd17ce7e49a0a0203f03b706b39628c4d913a8607"
 dependencies = [
 "bytemuck",
- "read-fonts",
+ "read-fonts 0.29.3",
+]
+
+[[package]]
+name = "skrifa"
+version = "0.33.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78cc1f79e5624f166718224ef883095bea315801aca75b62c64f3937755a586d"
+dependencies = [
+ "bytemuck",
+ "read-fonts 0.31.3",
 ]

 [[package]]
@@ -8407,7 +8485,7 @@ dependencies = [
 "getrandom 0.3.3",
 "once_cell",
 "rustix 1.0.8",
- "windows-sys 0.59.0",
+ "windows-sys 0.52.0",
 ]

 [[package]]
@@ -9176,7 +9254,7 @@ dependencies = [
 "log",
 "peniko",
 "png",
- "skrifa",
+ "skrifa 0.31.3",
 "static_assertions",
 "thiserror 2.0.12",
 "vello_encoding",
@@ -9184,6 +9262,20 @@ dependencies = [
 "wgpu",
 ]

+[[package]]
+name = "vello_common"
+version = "0.0.1"
+source = "git+https://github.com/linebender/vello?rev=931e6fdc135507486324adec019edffa2f70a203#931e6fdc135507486324adec019edffa2f70a203"
+dependencies = [
+ "bytemuck",
+ "fearless_simd",
+ "log",
+ "peniko",
+ "png",
+ "skrifa 0.31.3",
+ "smallvec",
+]
+
 [[package]]
 name = "vello_common"
 version = "0.0.1"
@@ -9194,17 +9286,26 @@ dependencies = [
 "log",
 "peniko",
 "png",
- "skrifa",
+ "skrifa 0.31.3",
 "smallvec",
 ]

+[[package]]
+name = "vello_cpu"
+version = "0.0.1"
+source = "git+https://github.com/linebender/vello?rev=931e6fdc135507486324adec019edffa2f70a203#931e6fdc135507486324adec019edffa2f70a203"
+dependencies = [
+ "bytemuck",
+ "vello_common 0.0.1 (git+https://github.com/linebender/vello?rev=931e6fdc135507486324adec019edffa2f70a203)",
+]
+
 [[package]]
 name = "vello_cpu"
 version = "0.0.1"
 source = "git+https://github.com/linebender/vello?rev=b0e2e598ac62c7b3d04d8660e7b1b7659b596970#b0e2e598ac62c7b3d04d8660e7b1b7659b596970"
 dependencies = [
 "bytemuck",
- "vello_common",
+ "vello_common 0.0.1 (git+https://github.com/linebender/vello?rev=b0e2e598ac62c7b3d04d8660e7b1b7659b596970)",
 ]

 [[package]]
@@ -9215,7 +9316,7 @@ dependencies = [
 "bytemuck",
 "guillotiere",
 "peniko",
- "skrifa",
+ "skrifa 0.31.3",
 "smallvec",
 ]

@@ -9663,7 +9764,6 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.66.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "allocator-api2",
 "bincode",
@@ -9698,7 +9798,6 @@ dependencies = [
 [[package]]
 name = "webrender_api"
 version = "0.66.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "app_units",
 "bitflags 2.9.1",
@@ -9719,7 +9818,6 @@ dependencies = [
 [[package]]
 name = "webrender_build"
 version = "0.0.2"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "bitflags 2.9.1",
 "lazy_static",
@@ -9942,7 +10040,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.59.0",
+ "windows-sys 0.48.0",
 ]

 [[package]]
@@ -10431,24 +10529,27 @@ dependencies = [
 [[package]]
 name = "wr_glyph_rasterizer"
 version = "0.1.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "core-foundation 0.9.4",
 "core-graphics",
 "core-text",
 "dwrote",
 "euclid",
+ "fontique",
 "freetype",
 "fxhash",
 "lazy_static",
 "libc",
 "log",
 "malloc_size_of_derive",
+ "memmap2",
 "objc",
 "rayon",
 "serde",
+ "skrifa 0.31.3",
 "smallvec",
 "tracy-rs",
+ "vello_cpu 0.0.1 (git+https://github.com/linebender/vello?rev=931e6fdc135507486324adec019edffa2f70a203)",
 "webrender_api",
 "wr_malloc_size_of",
 ]
@@ -10456,7 +10557,6 @@ dependencies = [
 [[package]]
 name = "wr_malloc_size_of"
 version = "0.2.0"
-source = "git+https://github.com/servo/webrender?branch=0.67#15318d6627e91ec19fc0a44a7434b08673413140"
 dependencies = [
 "app_units",
 "euclid",
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -75,6 +75,7 @@ gstreamer-gl-sys = "0.23"
 gstreamer-sys = "0.23"
 gstreamer-video = "0.23"
 harfbuzz-sys = "0.6.1"
+harfrust = "0.1.1"
 headers = "0.4"
 hitrace = "0.1.5"
 html5ever = "0.35"
@@ -122,7 +123,7 @@ rand_core = "0.6"
 rand_isaac = "0.3"
 raw-window-handle = "0.6"
 rayon = "1"
-read-fonts = "0.29.2"
+read-fonts = "0.31.3"
 regex = "1.11"
 resvg = "0.45.0"
 rustls = { version = "0.23", default-features = false, features = ["logging", "std", "tls12"] }
@@ -138,7 +139,7 @@ servo-media-dummy = { git = "https://github.com/servo/media" }
 servo-media-gstreamer = { git = "https://github.com/servo/media" }
 servo-tracing = { path = "components/servo_tracing" }
 servo_arc = { git = "https://github.com/servo/stylo", branch = "2025-08-01" }
-skrifa = "0.31.3"
+skrifa = "0.33.2"
 smallbitvec = "2.6.0"
 smallvec = { version = "1.15", features = ["serde", "union"] }
 string_cache = "0.8"
@@ -178,8 +179,8 @@ vello_cpu = { git = "https://github.com/linebender/vello", rev = "b0e2e598ac62c7
 webdriver = "0.53.0"
 webgpu_traits = { path = "components/shared/webgpu" }
 webpki-roots = "1.0"
-webrender = { git = "https://github.com/servo/webrender", branch = "0.67", features = ["capture"] }
-webrender_api = { git = "https://github.com/servo/webrender", branch = "0.67" }
+webrender = { git = "https://github.com/servo/webrender", branch = "fontations", features = ["capture", "fontations"] }
+webrender_api = { git = "https://github.com/servo/webrender", branch = "fontations" }
 webxr-api = { path = "components/shared/webxr" }
 wgpu-core = "25"
 wgpu-types = "25"
@@ -187,7 +188,7 @@ winapi = "0.3"
 windows-sys = "0.59"
 winit = "0.30.12"
 wio = "0.2"
-wr_malloc_size_of = { git = "https://github.com/servo/webrender", branch = "0.67" }
+wr_malloc_size_of = { git = "https://github.com/servo/webrender", branch = "fontations" }
 xi-unicode = "0.3.0"
 xml5ever = "0.35"

--- a/components/canvas/peniko_conversions.rs
+++ b/components/canvas/peniko_conversions.rs
@@ -9,6 +9,13 @@ use style::color::AbsoluteColor;
 use crate::backend::Convert;
 use crate::canvas_data::Filter;

+impl Convert<peniko::Font> for fonts::RawFont {
+    fn convert(self) -> peniko::Font {
+        use std::sync::Arc;
+        peniko::Font::new(peniko::Blob::new(Arc::new(self.data)), self.index)
+    }
+}
+
 impl Convert<kurbo::Join> for LineJoinStyle {
    fn convert(self) -> kurbo::Join {
        match self {
--- a/components/canvas/raqote_backend.rs
+++ b/components/canvas/raqote_backend.rs
@@ -333,8 +333,9 @@ impl GenericDrawTarget for raqote::DrawTarget {
            SHARED_FONT_CACHE.with(|font_cache| {
                let identifier = template.identifier();
                if !font_cache.borrow().contains_key(&identifier) {
-                    let data = std::sync::Arc::new(run.font.data().as_ref().to_vec());
-                    let Ok(font) = Font::from_bytes(data, identifier.index()) else {
+                    let raw_font = run.font.raw_font();
+                    let data = std::sync::Arc::new(raw_font.data.as_ref().to_vec());
+                    let Ok(font) = Font::from_bytes(data, raw_font.index) else {
                        return;
                    };
                    font_cache.borrow_mut().insert(identifier.clone(), font);
--- a/components/canvas/vello_backend.rs
+++ b/components/canvas/vello_backend.rs
@@ -402,13 +402,8 @@ impl GenericDrawTarget for VelloDrawTarget {
                SHARED_FONT_CACHE.with(|font_cache| {
                    let identifier = template.identifier();
                    if !font_cache.borrow().contains_key(&identifier) {
-                        font_cache.borrow_mut().insert(
-                            identifier.clone(),
-                            peniko::Font::new(
-                                peniko::Blob::from(run.font.data().as_ref().to_vec()),
-                                identifier.index(),
-                            ),
-                        );
+                        let font = run.font.raw_font().clone().convert();
+                        font_cache.borrow_mut().insert(identifier.clone(), font);
                    }

                    let font_cache = font_cache.borrow();
--- a/components/canvas/vello_cpu_backend.rs
+++ b/components/canvas/vello_cpu_backend.rs
@@ -305,13 +305,8 @@ impl GenericDrawTarget for VelloCPUDrawTarget {
                SHARED_FONT_CACHE.with(|font_cache| {
                    let identifier = template.identifier();
                    if !font_cache.borrow().contains_key(&identifier) {
-                        font_cache.borrow_mut().insert(
-                            identifier.clone(),
-                            peniko::Font::new(
-                                peniko::Blob::from(run.font.data().as_ref().to_vec()),
-                                identifier.index(),
-                            ),
-                        );
+                        let font = run.font.raw_font().clone().convert();
+                        font_cache.borrow_mut().insert(identifier.clone(), font);
                    }

                    let font_cache = font_cache.borrow();
--- a/components/fonts/Cargo.toml
+++ b/components/fonts/Cargo.toml
@@ -14,6 +14,9 @@ test = true
 doctest = false

 [features]
+default = ["harfrust"]
+harfbuzz = ["dep:harfbuzz-sys"]
+harfrust = ["dep:harfrust"]
 tracing = ["dep:tracing"]

 [dependencies]
@@ -27,7 +30,8 @@ fnv = { workspace = true }
 fonts_traits = { workspace = true }
 fontsan = { git = "https://github.com/servo/fontsan" }
 # FIXME (#34517): macOS only needs this when building libservo without `--features media-gstreamer`
-harfbuzz-sys = { workspace = true, features = ["bundled"] }
+harfbuzz-sys = { workspace = true, optional = true, features = ["bundled"] }
+harfrust = { workspace = true, optional = true }
 ipc-channel = { workspace = true }
 itertools = { workspace = true }
 libc = { workspace = true }
--- a/components/fonts/font.rs
+++ b/components/fonts/font.rs
@@ -32,7 +32,7 @@ pub use crate::platform::font_list::fallback_font_families;
 use crate::{
    ByteIndex, EmojiPresentationPreference, FallbackFontSelectionOptions, FontContext, FontData,
    FontIdentifier, FontTemplateDescriptor, FontTemplateRef, FontTemplateRefMethods, GlyphData,
-    GlyphId, GlyphStore, LocalFontIdentifier, Shaper,
+    GlyphId, GlyphStore, LocalFontIdentifier, Shaper, TShaper as _,
 };

 #[macro_export]
@@ -49,6 +49,7 @@ pub const SBIX: u32 = ot_tag!('s', 'b', 'i', 'x');
 pub const CBDT: u32 = ot_tag!('C', 'B', 'D', 'T');
 pub const COLR: u32 = ot_tag!('C', 'O', 'L', 'R');
 pub const BASE: u32 = ot_tag!('B', 'A', 'S', 'E');
+pub const LIGA: u32 = ot_tag!('l', 'i', 'g', 'a');

 pub const LAST_RESORT_GLYPH_ADVANCE: FractionalPixel = 10.0;

@@ -227,6 +228,15 @@ impl malloc_size_of::MallocSizeOf for CachedShapeData {
    }
 }

+/// Raw data and index for a font
+#[derive(Clone)]
+pub struct RawFont {
+    /// The raw font file data (.ttf, .otf, .ttc, etc)
+    pub data: FontData,
+    /// The index of the font within the file (0 if the file is not a ttc)
+    pub index: u32,
+}
+
 pub struct Font {
    pub handle: PlatformFont,
    pub template: FontTemplateRef,
@@ -234,7 +244,7 @@ pub struct Font {
    pub descriptor: FontDescriptor,

    /// The data for this font. This might be uninitialized for system fonts.
-    data: OnceLock<FontData>,
+    raw: OnceLock<RawFont>,

    shaper: OnceLock<Shaper>,
    cached_shape_data: RwLock<CachedShapeData>,
@@ -288,7 +298,9 @@ impl Font {
            template,
            metrics,
            descriptor,
-            data: data.map(OnceLock::from).unwrap_or_default(),
+            raw: data
+                .map(|data| OnceLock::from(RawFont { data, index: 0 }))
+                .unwrap_or_default(),
            shaper: OnceLock::new(),
            cached_shape_data: Default::default(),
            font_instance_key: Default::default(),
@@ -323,16 +335,18 @@ impl Font {

    /// Return the data for this `Font`. Note that this is currently highly inefficient for system
    /// fonts and should not be used except in legacy canvas code.
-    pub fn data(&self) -> &FontData {
-        self.data.get_or_init(|| {
+    pub fn raw_font(&self) -> &RawFont {
+        self.raw.get_or_init(|| {
            let FontIdentifier::Local(local_font_identifier) = self.identifier() else {
                unreachable!("All web fonts should already have initialized data");
            };
-            FontData::from_bytes(
-                &local_font_identifier
-                    .read_data_from_file()
-                    .unwrap_or_default(),
-            )
+            let Some((bytes, index)) = local_font_identifier.read_data_from_file() else {
+                panic!("Failed to load raw font data");
+            };
+
+            let data = FontData::from_bytes(&bytes);
+
+            RawFont { data, index }
        })
    }
 }
@@ -425,9 +439,8 @@ impl Font {
    }

    fn shape_text_harfbuzz(&self, text: &str, options: &ShapingOptions, glyphs: &mut GlyphStore) {
-        let this = self as *const Font;
        self.shaper
-            .get_or_init(|| Shaper::new(this))
+            .get_or_init(|| Shaper::new(self))
            .shape_text(text, options, glyphs);
    }

@@ -543,8 +556,7 @@ impl Font {

    /// Get the [`FontBaseline`] for this font.
    pub fn baseline(&self) -> Option<FontBaseline> {
-        let this = self as *const Font;
-        self.shaper.get_or_init(|| Shaper::new(this)).baseline()
+        self.shaper.get_or_init(|| Shaper::new(self)).baseline()
    }
 }

--- a/components/fonts/lib.rs
+++ b/components/fonts/lib.rs
@@ -11,7 +11,7 @@ mod font_template;
 mod glyph;
 #[allow(unsafe_code)]
 pub mod platform;
-mod shaper;
+mod shapers;
 mod system_font_service;

 use std::sync::Arc;
@@ -23,7 +23,7 @@ pub use font_template::*;
 pub use glyph::*;
 use ipc_channel::ipc::IpcSharedMemory;
 pub use platform::LocalFontIdentifier;
-pub use shaper::*;
+pub use shapers::*;
 pub use system_font_service::*;
 use unicode_properties::{EmojiStatus, UnicodeEmoji, emoji};

@@ -106,10 +106,12 @@ impl FallbackFontSelectionOptions {
    }
 }

+#[cfg(feature = "harfbuzz")]
 pub(crate) fn float_to_fixed(before: usize, f: f64) -> i32 {
    ((1i32 << before) as f64 * f) as i32
 }

+#[cfg(feature = "harfbuzz")]
 pub(crate) fn fixed_to_float(before: usize, f: i32) -> f64 {
    f as f64 * 1.0f64 / ((1i32 << before) as f64)
 }
--- a/components/fonts/platform/freetype/mod.rs
+++ b/components/fonts/platform/freetype/mod.rs
@@ -56,9 +56,9 @@ impl LocalFontIdentifier {
        }
    }

-    pub(crate) fn read_data_from_file(&self) -> Option<Vec<u8>> {
+    pub(crate) fn read_data_from_file(&self) -> Option<(Vec<u8>, u32)> {
        let file = File::open(Path::new(&*self.path)).ok()?;
        let mmap = unsafe { Mmap::map(&file).ok()? };
-        Some(mmap[..].to_vec())
+        Some((mmap[..].to_vec(), self.variation_index as u32))
    }
 }
--- a/components/fonts/platform/macos/font_list.rs
+++ b/components/fonts/platform/macos/font_list.rs
@@ -9,6 +9,7 @@ use base::text::{UnicodeBlock, UnicodeBlockMethod, unicode_plane};
 use log::debug;
 use malloc_size_of_derive::MallocSizeOf;
 use memmap2::Mmap;
+use read_fonts::FileRef;
 use serde::{Deserialize, Serialize};
 use style::Atom;
 use style::values::computed::font::GenericFontFamily;
@@ -43,7 +44,7 @@ impl LocalFontIdentifier {
        0
    }

-    pub(crate) fn read_data_from_file(&self) -> Option<Vec<u8>> {
+    pub(crate) fn read_data_from_file(&self) -> Option<(Vec<u8>, u32)> {
        // TODO: This is incorrect, if the font file is a TTC (collection) with more than
        // one font. In that case we either need to reconstruct the pertinent tables into
        // a bundle of font data (expensive) or make sure that the value returned by
@@ -52,7 +53,48 @@ impl LocalFontIdentifier {
        // listed in the font.
        let file = File::open(Path::new(&*self.path)).ok()?;
        let mmap = unsafe { Mmap::map(&file).ok()? };
-        Some(mmap[..].to_vec())
+
+        // Determine index
+        let file_ref = FileRef::new(mmap.as_ref()).ok()?;
+        let index = ttc_index_from_postscript_name(file_ref, &self.postscript_name);
+
+        Some((mmap[..].to_vec(), index))
+    }
+}
+
+/// CoreText font enumaration gives us a postscript name rather than an index.
+/// This functions maps from postscript name to index
+fn ttc_index_from_postscript_name(font_file: FileRef<'_>, postscript_name: &str) -> u32 {
+    use read_fonts::types::NameId;
+    use read_fonts::{FileRef, TableProvider as _};
+
+    match font_file {
+        FileRef::Font(_) => 0,
+        FileRef::Collection(collection) => 'idx: {
+            for i in 0..collection.len() {
+                let font = collection.get(i).unwrap();
+                let name_table = font.name().unwrap();
+                if name_table
+                    .name_record()
+                    .iter()
+                    .filter(|record| record.name_id() == NameId::POSTSCRIPT_NAME)
+                    .any(|record| {
+                        record
+                            .string(name_table.string_data())
+                            .unwrap()
+                            .chars()
+                            .eq(postscript_name.chars())
+                    })
+                {
+                    break 'idx i;
+                }
+            }
+
+            panic!(
+                "Font with postscript_name {} not found in collection",
+                postscript_name
+            );
+        },
    }
 }

--- a/components/fonts/platform/windows/font_list.rs
+++ b/components/fonts/platform/windows/font_list.rs
@@ -67,14 +67,15 @@ impl LocalFontIdentifier {
        }
    }

-    pub(crate) fn read_data_from_file(&self) -> Option<Vec<u8>> {
+    pub(crate) fn read_data_from_file(&self) -> Option<(Vec<u8>, u32)> {
        let font = FontCollection::system()
            .font_from_descriptor(&self.font_descriptor)
            .ok()??;
        let face = font.create_font_face();
+        let index = face.get_index();
        let files = face.get_files();
        assert!(!files.is_empty());
-        Some(files[0].get_font_file_bytes())
+        Some((files[0].get_font_file_bytes(), index))
    }
 }

--- a/components/fonts/shaper.rs
+++ b/components/fonts/shaper.rs
@@ -1,735 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
-
-#![allow(unsafe_code)]
-
-use std::os::raw::{c_char, c_int, c_uint, c_void};
-use std::sync::LazyLock;
-use std::{char, cmp, ptr};
-
-use app_units::Au;
-use base::text::is_bidi_control;
-use euclid::default::Point2D;
-// Eventually we would like the shaper to be pluggable, as many operating systems have their own
-// shapers. For now, however, HarfBuzz is a hard dependency.
-use harfbuzz_sys::{
-    HB_DIRECTION_LTR, HB_DIRECTION_RTL, HB_MEMORY_MODE_READONLY, HB_OT_LAYOUT_BASELINE_TAG_HANGING,
-    HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT, HB_OT_LAYOUT_BASELINE_TAG_ROMAN,
-    hb_blob_create, hb_blob_t, hb_bool_t, hb_buffer_add_utf8, hb_buffer_create, hb_buffer_destroy,
-    hb_buffer_get_glyph_infos, hb_buffer_get_glyph_positions, hb_buffer_get_length,
-    hb_buffer_set_direction, hb_buffer_set_script, hb_buffer_t, hb_codepoint_t,
-    hb_face_create_for_tables, hb_face_destroy, hb_face_t, hb_feature_t, hb_font_create,
-    hb_font_destroy, hb_font_funcs_create, hb_font_funcs_set_glyph_h_advance_func,
-    hb_font_funcs_set_nominal_glyph_func, hb_font_funcs_t, hb_font_set_funcs, hb_font_set_ppem,
-    hb_font_set_scale, hb_font_t, hb_glyph_info_t, hb_glyph_position_t, hb_ot_layout_get_baseline,
-    hb_position_t, hb_shape, hb_tag_t,
-};
-use log::debug;
-use num_traits::Zero;
-
-use crate::font::advance_for_shaped_glyph;
-use crate::platform::font::FontTable;
-use crate::{
-    BASE, ByteIndex, Font, FontBaseline, FontTableMethods, FontTableTag, GlyphData, GlyphId,
-    GlyphStore, KERN, ShapingFlags, ShapingOptions, fixed_to_float, float_to_fixed, ot_tag,
-};
-
-const NO_GLYPH: i32 = -1;
-const LIGA: u32 = ot_tag!('l', 'i', 'g', 'a');
-const HB_OT_TAG_DEFAULT_SCRIPT: u32 = ot_tag!('D', 'F', 'L', 'T');
-const HB_OT_TAG_DEFAULT_LANGUAGE: u32 = ot_tag!('d', 'f', 'l', 't');
-
-pub struct ShapedGlyphData {
-    count: usize,
-    glyph_infos: *mut hb_glyph_info_t,
-    pos_infos: *mut hb_glyph_position_t,
-}
-
-pub struct ShapedGlyphEntry {
-    codepoint: GlyphId,
-    advance: Au,
-    offset: Option<Point2D<Au>>,
-}
-
-impl ShapedGlyphData {
-    /// Create a new [`ShapedGlyphData`] from the given HarfBuzz buffer.
-    ///
-    /// # Safety
-    ///
-    /// Passing an invalid buffer pointer to this function results in undefined behavior.
-    pub unsafe fn new(buffer: *mut hb_buffer_t) -> ShapedGlyphData {
-        let mut glyph_count = 0;
-        let glyph_infos = unsafe { hb_buffer_get_glyph_infos(buffer, &mut glyph_count) };
-        assert!(!glyph_infos.is_null());
-        let mut pos_count = 0;
-        let pos_infos = unsafe { hb_buffer_get_glyph_positions(buffer, &mut pos_count) };
-        assert!(!pos_infos.is_null());
-        assert_eq!(glyph_count, pos_count);
-
-        ShapedGlyphData {
-            count: glyph_count as usize,
-            glyph_infos,
-            pos_infos,
-        }
-    }
-
-    #[inline(always)]
-    fn byte_offset_of_glyph(&self, i: usize) -> u32 {
-        assert!(i < self.count);
-
-        unsafe {
-            let glyph_info_i = self.glyph_infos.add(i);
-            (*glyph_info_i).cluster
-        }
-    }
-
-    pub fn len(&self) -> usize {
-        self.count
-    }
-
-    pub fn is_empty(&self) -> bool {
-        self.count == 0
-    }
-
-    /// Returns shaped glyph data for one glyph, and updates the y-position of the pen.
-    pub fn entry_for_glyph(&self, i: usize, y_pos: &mut Au) -> ShapedGlyphEntry {
-        assert!(i < self.count);
-
-        unsafe {
-            let glyph_info_i = self.glyph_infos.add(i);
-            let pos_info_i = self.pos_infos.add(i);
-            let x_offset = Shaper::fixed_to_float((*pos_info_i).x_offset);
-            let y_offset = Shaper::fixed_to_float((*pos_info_i).y_offset);
-            let x_advance = Shaper::fixed_to_float((*pos_info_i).x_advance);
-            let y_advance = Shaper::fixed_to_float((*pos_info_i).y_advance);
-
-            let x_offset = Au::from_f64_px(x_offset);
-            let y_offset = Au::from_f64_px(y_offset);
-            let x_advance = Au::from_f64_px(x_advance);
-            let y_advance = Au::from_f64_px(y_advance);
-
-            let offset = if x_offset.is_zero() && y_offset.is_zero() && y_advance.is_zero() {
-                None
-            } else {
-                // adjust the pen..
-                if y_advance > Au::zero() {
-                    *y_pos -= y_advance;
-                }
-
-                Some(Point2D::new(x_offset, *y_pos - y_offset))
-            };
-
-            ShapedGlyphEntry {
-                codepoint: (*glyph_info_i).codepoint as GlyphId,
-                advance: x_advance,
-                offset,
-            }
-        }
-    }
-}
-
-#[derive(Debug)]
-pub struct Shaper {
-    hb_face: *mut hb_face_t,
-    hb_font: *mut hb_font_t,
-    font: *const Font,
-}
-
-// The HarfBuzz API is thread safe as well as our `Font`, so we can make the data
-// structures here as thread-safe as well. This doesn't seem to be documented,
-// but was expressed as one of the original goals of the HarfBuzz API.
-unsafe impl Sync for Shaper {}
-unsafe impl Send for Shaper {}
-
-impl Drop for Shaper {
-    fn drop(&mut self) {
-        unsafe {
-            assert!(!self.hb_face.is_null());
-            hb_face_destroy(self.hb_face);
-
-            assert!(!self.hb_font.is_null());
-            hb_font_destroy(self.hb_font);
-        }
-    }
-}
-
-impl Shaper {
-    #[allow(clippy::not_unsafe_ptr_arg_deref)] // Has an unsafe block inside
-    pub fn new(font: *const Font) -> Shaper {
-        unsafe {
-            let hb_face: *mut hb_face_t = hb_face_create_for_tables(
-                Some(font_table_func),
-                font as *const c_void as *mut c_void,
-                None,
-            );
-            let hb_font: *mut hb_font_t = hb_font_create(hb_face);
-
-            // Set points-per-em. if zero, performs no hinting in that direction.
-            let pt_size = (*font).descriptor.pt_size.to_f64_px();
-            hb_font_set_ppem(hb_font, pt_size as c_uint, pt_size as c_uint);
-
-            // Set scaling. Note that this takes 16.16 fixed point.
-            hb_font_set_scale(
-                hb_font,
-                Shaper::float_to_fixed(pt_size) as c_int,
-                Shaper::float_to_fixed(pt_size) as c_int,
-            );
-
-            // configure static function callbacks.
-            hb_font_set_funcs(
-                hb_font,
-                HB_FONT_FUNCS.0,
-                font as *mut Font as *mut c_void,
-                None,
-            );
-
-            Shaper {
-                hb_face,
-                hb_font,
-                font,
-            }
-        }
-    }
-
-    fn float_to_fixed(f: f64) -> i32 {
-        float_to_fixed(16, f)
-    }
-
-    fn fixed_to_float(i: hb_position_t) -> f64 {
-        fixed_to_float(16, i)
-    }
-}
-
-pub fn unicode_to_hb_script(script: unicode_script::Script) -> harfbuzz_sys::hb_script_t {
-    use harfbuzz_sys::*;
-    use unicode_script::Script::*;
-    match script {
-        Adlam => HB_SCRIPT_ADLAM,
-        Ahom => HB_SCRIPT_AHOM,
-        Anatolian_Hieroglyphs => HB_SCRIPT_ANATOLIAN_HIEROGLYPHS,
-        Arabic => HB_SCRIPT_ARABIC,
-        Armenian => HB_SCRIPT_ARMENIAN,
-        Avestan => HB_SCRIPT_AVESTAN,
-        Balinese => HB_SCRIPT_BALINESE,
-        Bamum => HB_SCRIPT_BAMUM,
-        Bassa_Vah => HB_SCRIPT_BASSA_VAH,
-        Batak => HB_SCRIPT_BATAK,
-        Bengali => HB_SCRIPT_BENGALI,
-        Bhaiksuki => HB_SCRIPT_BHAIKSUKI,
-        Bopomofo => HB_SCRIPT_BOPOMOFO,
-        Brahmi => HB_SCRIPT_BRAHMI,
-        Braille => HB_SCRIPT_BRAILLE,
-        Buginese => HB_SCRIPT_BUGINESE,
-        Buhid => HB_SCRIPT_BUHID,
-        Canadian_Aboriginal => HB_SCRIPT_CANADIAN_SYLLABICS,
-        Carian => HB_SCRIPT_CARIAN,
-        Caucasian_Albanian => HB_SCRIPT_CAUCASIAN_ALBANIAN,
-        Chakma => HB_SCRIPT_CHAKMA,
-        Cham => HB_SCRIPT_CHAM,
-        Cherokee => HB_SCRIPT_CHEROKEE,
-        Chorasmian => HB_SCRIPT_CHORASMIAN,
-        Common => HB_SCRIPT_COMMON,
-        Coptic => HB_SCRIPT_COPTIC,
-        Cuneiform => HB_SCRIPT_CUNEIFORM,
-        Cypriot => HB_SCRIPT_CYPRIOT,
-        Cyrillic => HB_SCRIPT_CYRILLIC,
-        Deseret => HB_SCRIPT_DESERET,
-        Devanagari => HB_SCRIPT_DEVANAGARI,
-        Dives_Akuru => HB_SCRIPT_DIVES_AKURU,
-        Dogra => HB_SCRIPT_DOGRA,
-        Duployan => HB_SCRIPT_DUPLOYAN,
-        Egyptian_Hieroglyphs => HB_SCRIPT_EGYPTIAN_HIEROGLYPHS,
-        Elbasan => HB_SCRIPT_ELBASAN,
-        Elymaic => HB_SCRIPT_ELYMAIC,
-        Ethiopic => HB_SCRIPT_ETHIOPIC,
-        Georgian => HB_SCRIPT_GEORGIAN,
-        Glagolitic => HB_SCRIPT_GLAGOLITIC,
-        Gothic => HB_SCRIPT_GOTHIC,
-        Grantha => HB_SCRIPT_GRANTHA,
-        Greek => HB_SCRIPT_GREEK,
-        Gujarati => HB_SCRIPT_GUJARATI,
-        Gunjala_Gondi => HB_SCRIPT_GUNJALA_GONDI,
-        Gurmukhi => HB_SCRIPT_GURMUKHI,
-        Han => HB_SCRIPT_HAN,
-        Hangul => HB_SCRIPT_HANGUL,
-        Hanifi_Rohingya => HB_SCRIPT_HANIFI_ROHINGYA,
-        Hanunoo => HB_SCRIPT_HANUNOO,
-        Hatran => HB_SCRIPT_HATRAN,
-        Hebrew => HB_SCRIPT_HEBREW,
-        Hiragana => HB_SCRIPT_HIRAGANA,
-        Imperial_Aramaic => HB_SCRIPT_IMPERIAL_ARAMAIC,
-        Inherited => HB_SCRIPT_INHERITED,
-        Inscriptional_Pahlavi => HB_SCRIPT_INSCRIPTIONAL_PAHLAVI,
-        Inscriptional_Parthian => HB_SCRIPT_INSCRIPTIONAL_PARTHIAN,
-        Javanese => HB_SCRIPT_JAVANESE,
-        Kaithi => HB_SCRIPT_KAITHI,
-        Kannada => HB_SCRIPT_KANNADA,
-        Katakana => HB_SCRIPT_KATAKANA,
-        Kayah_Li => HB_SCRIPT_KAYAH_LI,
-        Kharoshthi => HB_SCRIPT_KHAROSHTHI,
-        Khitan_Small_Script => HB_SCRIPT_KHITAN_SMALL_SCRIPT,
-        Khmer => HB_SCRIPT_KHMER,
-        Khojki => HB_SCRIPT_KHOJKI,
-        Khudawadi => HB_SCRIPT_KHUDAWADI,
-        Lao => HB_SCRIPT_LAO,
-        Latin => HB_SCRIPT_LATIN,
-        Lepcha => HB_SCRIPT_LEPCHA,
-        Limbu => HB_SCRIPT_LIMBU,
-        Linear_A => HB_SCRIPT_LINEAR_A,
-        Linear_B => HB_SCRIPT_LINEAR_B,
-        Lisu => HB_SCRIPT_LISU,
-        Lycian => HB_SCRIPT_LYCIAN,
-        Lydian => HB_SCRIPT_LYDIAN,
-        Mahajani => HB_SCRIPT_MAHAJANI,
-        Makasar => HB_SCRIPT_MAKASAR,
-        Malayalam => HB_SCRIPT_MALAYALAM,
-        Mandaic => HB_SCRIPT_MANDAIC,
-        Manichaean => HB_SCRIPT_MANICHAEAN,
-        Marchen => HB_SCRIPT_MARCHEN,
-        Masaram_Gondi => HB_SCRIPT_MASARAM_GONDI,
-        Medefaidrin => HB_SCRIPT_MEDEFAIDRIN,
-        Meetei_Mayek => HB_SCRIPT_MEETEI_MAYEK,
-        Mende_Kikakui => HB_SCRIPT_MENDE_KIKAKUI,
-        Meroitic_Cursive => HB_SCRIPT_MEROITIC_CURSIVE,
-        Meroitic_Hieroglyphs => HB_SCRIPT_MEROITIC_HIEROGLYPHS,
-        Miao => HB_SCRIPT_MIAO,
-        Modi => HB_SCRIPT_MODI,
-        Mongolian => HB_SCRIPT_MONGOLIAN,
-        Mro => HB_SCRIPT_MRO,
-        Multani => HB_SCRIPT_MULTANI,
-        Myanmar => HB_SCRIPT_MYANMAR,
-        Nabataean => HB_SCRIPT_NABATAEAN,
-        Nandinagari => HB_SCRIPT_NANDINAGARI,
-        New_Tai_Lue => HB_SCRIPT_NEW_TAI_LUE,
-        Newa => HB_SCRIPT_NEWA,
-        Nko => HB_SCRIPT_NKO,
-        Nushu => HB_SCRIPT_NUSHU,
-        Nyiakeng_Puachue_Hmong => HB_SCRIPT_NYIAKENG_PUACHUE_HMONG,
-        Ogham => HB_SCRIPT_OGHAM,
-        Ol_Chiki => HB_SCRIPT_OL_CHIKI,
-        Old_Hungarian => HB_SCRIPT_OLD_HUNGARIAN,
-        Old_Italic => HB_SCRIPT_OLD_ITALIC,
-        Old_North_Arabian => HB_SCRIPT_OLD_NORTH_ARABIAN,
-        Old_Permic => HB_SCRIPT_OLD_PERMIC,
-        Old_Persian => HB_SCRIPT_OLD_PERSIAN,
-        Old_Sogdian => HB_SCRIPT_OLD_SOGDIAN,
-        Old_South_Arabian => HB_SCRIPT_OLD_SOUTH_ARABIAN,
-        Old_Turkic => HB_SCRIPT_OLD_TURKIC,
-        Oriya => HB_SCRIPT_ORIYA,
-        Osage => HB_SCRIPT_OSAGE,
-        Osmanya => HB_SCRIPT_OSMANYA,
-        Pahawh_Hmong => HB_SCRIPT_PAHAWH_HMONG,
-        Palmyrene => HB_SCRIPT_PALMYRENE,
-        Pau_Cin_Hau => HB_SCRIPT_PAU_CIN_HAU,
-        Phags_Pa => HB_SCRIPT_PHAGS_PA,
-        Phoenician => HB_SCRIPT_PHOENICIAN,
-        Psalter_Pahlavi => HB_SCRIPT_PSALTER_PAHLAVI,
-        Rejang => HB_SCRIPT_REJANG,
-        Runic => HB_SCRIPT_RUNIC,
-        Samaritan => HB_SCRIPT_SAMARITAN,
-        Saurashtra => HB_SCRIPT_SAURASHTRA,
-        Sharada => HB_SCRIPT_SHARADA,
-        Shavian => HB_SCRIPT_SHAVIAN,
-        Siddham => HB_SCRIPT_SIDDHAM,
-        SignWriting => HB_SCRIPT_SIGNWRITING,
-        Sinhala => HB_SCRIPT_SINHALA,
-        Sogdian => HB_SCRIPT_SOGDIAN,
-        Sora_Sompeng => HB_SCRIPT_SORA_SOMPENG,
-        Soyombo => HB_SCRIPT_SOYOMBO,
-        Sundanese => HB_SCRIPT_SUNDANESE,
-        Syloti_Nagri => HB_SCRIPT_SYLOTI_NAGRI,
-        Syriac => HB_SCRIPT_SYRIAC,
-        Tagalog => HB_SCRIPT_TAGALOG,
-        Tagbanwa => HB_SCRIPT_TAGBANWA,
-        Tai_Le => HB_SCRIPT_TAI_LE,
-        Tai_Tham => HB_SCRIPT_TAI_THAM,
-        Tai_Viet => HB_SCRIPT_TAI_VIET,
-        Takri => HB_SCRIPT_TAKRI,
-        Tamil => HB_SCRIPT_TAMIL,
-        Tangut => HB_SCRIPT_TANGUT,
-        Telugu => HB_SCRIPT_TELUGU,
-        Thaana => HB_SCRIPT_THAANA,
-        Thai => HB_SCRIPT_THAI,
-        Tibetan => HB_SCRIPT_TIBETAN,
-        Tifinagh => HB_SCRIPT_TIFINAGH,
-        Tirhuta => HB_SCRIPT_TIRHUTA,
-        Ugaritic => HB_SCRIPT_UGARITIC,
-        Unknown => HB_SCRIPT_UNKNOWN,
-        Vai => HB_SCRIPT_VAI,
-        Warang_Citi => HB_SCRIPT_WARANG_CITI,
-        Wancho => HB_SCRIPT_WANCHO,
-        Yezidi => HB_SCRIPT_YEZIDI,
-        Yi => HB_SCRIPT_YI,
-        Zanabazar_Square => HB_SCRIPT_ZANABAZAR_SQUARE,
-        _ => HB_SCRIPT_UNKNOWN,
-    }
-}
-
-impl Shaper {
-    /// Calculate the layout metrics associated with the given text when painted in a specific
-    /// font.
-    pub(crate) fn shape_text(&self, text: &str, options: &ShapingOptions, glyphs: &mut GlyphStore) {
-        unsafe {
-            let hb_buffer: *mut hb_buffer_t = hb_buffer_create();
-            hb_buffer_set_direction(
-                hb_buffer,
-                if options.flags.contains(ShapingFlags::RTL_FLAG) {
-                    HB_DIRECTION_RTL
-                } else {
-                    HB_DIRECTION_LTR
-                },
-            );
-
-            hb_buffer_set_script(hb_buffer, unicode_to_hb_script(options.script));
-
-            hb_buffer_add_utf8(
-                hb_buffer,
-                text.as_ptr() as *const c_char,
-                text.len() as c_int,
-                0,
-                text.len() as c_int,
-            );
-
-            let mut features = Vec::new();
-            if options
-                .flags
-                .contains(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG)
-            {
-                features.push(hb_feature_t {
-                    tag: LIGA,
-                    value: 0,
-                    start: 0,
-                    end: hb_buffer_get_length(hb_buffer),
-                })
-            }
-            if options
-                .flags
-                .contains(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
-            {
-                features.push(hb_feature_t {
-                    tag: KERN,
-                    value: 0,
-                    start: 0,
-                    end: hb_buffer_get_length(hb_buffer),
-                })
-            }
-
-            hb_shape(
-                self.hb_font,
-                hb_buffer,
-                features.as_mut_ptr(),
-                features.len() as u32,
-            );
-            self.save_glyph_results(text, options, glyphs, hb_buffer);
-            hb_buffer_destroy(hb_buffer);
-        }
-    }
-
-    fn save_glyph_results(
-        &self,
-        text: &str,
-        options: &ShapingOptions,
-        glyphs: &mut GlyphStore,
-        buffer: *mut hb_buffer_t,
-    ) {
-        let glyph_data = unsafe { ShapedGlyphData::new(buffer) };
-        let glyph_count = glyph_data.len();
-        let byte_max = text.len();
-
-        debug!(
-            "Shaped text[byte count={}], got back {} glyph info records.",
-            byte_max, glyph_count
-        );
-
-        // make map of what chars have glyphs
-        let mut byte_to_glyph = vec![NO_GLYPH; byte_max];
-
-        debug!("(glyph idx) -> (text byte offset)");
-        for i in 0..glyph_data.len() {
-            let loc = glyph_data.byte_offset_of_glyph(i) as usize;
-            if loc < byte_max {
-                byte_to_glyph[loc] = i as i32;
-            } else {
-                debug!(
-                    "ERROR: tried to set out of range byte_to_glyph: idx={}, glyph idx={}",
-                    loc, i
-                );
-            }
-            debug!("{} -> {}", i, loc);
-        }
-
-        debug!("text: {:?}", text);
-        debug!("(char idx): char->(glyph index):");
-        for (i, ch) in text.char_indices() {
-            debug!("{}: {:?} --> {}", i, ch, byte_to_glyph[i]);
-        }
-
-        let mut glyph_span = 0..0;
-        let mut byte_range = 0..0;
-
-        let mut y_pos = Au::zero();
-
-        // main loop over each glyph. each iteration usually processes 1 glyph and 1+ chars.
-        // in cases with complex glyph-character associations, 2+ glyphs and 1+ chars can be
-        // processed.
-        while glyph_span.start < glyph_count {
-            debug!("Processing glyph at idx={}", glyph_span.start);
-            glyph_span.end = glyph_span.start;
-            byte_range.end = glyph_data.byte_offset_of_glyph(glyph_span.start) as usize;
-
-            while byte_range.end < byte_max {
-                byte_range.end += 1;
-                // Extend the byte range to include any following byte without its own glyph.
-                while byte_range.end < byte_max && byte_to_glyph[byte_range.end] == NO_GLYPH {
-                    byte_range.end += 1;
-                }
-
-                // Extend the glyph range to include all glyphs covered by bytes processed so far.
-                let mut max_glyph_idx = glyph_span.end;
-                for glyph_idx in &byte_to_glyph[byte_range.clone()] {
-                    if *glyph_idx != NO_GLYPH {
-                        max_glyph_idx = cmp::max(*glyph_idx as usize + 1, max_glyph_idx);
-                    }
-                }
-                if max_glyph_idx > glyph_span.end {
-                    glyph_span.end = max_glyph_idx;
-                    debug!("Extended glyph span to {:?}", glyph_span);
-                }
-
-                // if there's just one glyph, then we don't need further checks.
-                if glyph_span.len() == 1 {
-                    break;
-                }
-
-                // if no glyphs were found yet, extend the char byte range more.
-                if glyph_span.is_empty() {
-                    continue;
-                }
-
-                // If byte_range now includes all the byte offsets found in glyph_span, then we
-                // have found a contiguous "cluster" and can stop extending it.
-                let mut all_glyphs_are_within_cluster: bool = true;
-                for j in glyph_span.clone() {
-                    let loc = glyph_data.byte_offset_of_glyph(j) as usize;
-                    if !(byte_range.start <= loc && loc < byte_range.end) {
-                        all_glyphs_are_within_cluster = false;
-                        break;
-                    }
-                }
-                if all_glyphs_are_within_cluster {
-                    break;
-                }
-
-                // Otherwise, the bytes we have seen so far correspond to a non-contiguous set of
-                // glyphs.  Keep extending byte_range until we fill in all the holes in the glyph
-                // span or reach the end of the text.
-            }
-
-            assert!(!byte_range.is_empty());
-            assert!(!glyph_span.is_empty());
-
-            // Now byte_range is the ligature clump formed by the glyphs in glyph_span.
-            // We will save these glyphs to the glyph store at the index of the first byte.
-            let byte_idx = ByteIndex(byte_range.start as isize);
-
-            if glyph_span.len() == 1 {
-                // Fast path: 1-to-1 mapping of byte offset to single glyph.
-                //
-                // TODO(Issue #214): cluster ranges need to be computed before
-                // shaping, and then consulted here.
-                // for now, just pretend that every character is a cluster start.
-                // (i.e., pretend there are no combining character sequences).
-                // 1-to-1 mapping of character to glyph also treated as ligature start.
-                //
-                // NB: When we acquire the ability to handle ligatures that cross word boundaries,
-                // we'll need to do something special to handle `word-spacing` properly.
-                let character = text[byte_range.clone()].chars().next().unwrap();
-                if is_bidi_control(character) {
-                    // Don't add any glyphs for bidi control chars
-                } else {
-                    let (glyph_id, advance, offset) = if character == '\t' {
-                        // Treat tabs in pre-formatted text as a fixed number of spaces. The glyph id does
-                        // not matter here as Servo doesn't render any glyphs for whitespace.
-                        //
-                        // TODO: Proper tab stops. This should happen in layout and be based on the
-                        // size of the space character of the inline formatting context.
-                        let font = unsafe { &(*self.font) };
-                        (
-                            font.glyph_index(' ').unwrap_or(0) as hb_codepoint_t,
-                            font.metrics.space_advance * 8,
-                            Default::default(),
-                        )
-                    } else {
-                        let shape = glyph_data.entry_for_glyph(glyph_span.start, &mut y_pos);
-                        let advance = advance_for_shaped_glyph(shape.advance, character, options);
-                        (shape.codepoint, advance, shape.offset)
-                    };
-
-                    let data = GlyphData::new(glyph_id, advance, offset, true, true);
-                    glyphs.add_glyph_for_byte_index(byte_idx, character, &data);
-                }
-            } else {
-                // collect all glyphs to be assigned to the first character.
-                let mut datas = vec![];
-
-                for glyph_i in glyph_span.clone() {
-                    let shape = glyph_data.entry_for_glyph(glyph_i, &mut y_pos);
-                    datas.push(GlyphData::new(
-                        shape.codepoint,
-                        shape.advance,
-                        shape.offset,
-                        true, // treat as cluster start
-                        glyph_i > glyph_span.start,
-                    ));
-                    // all but first are ligature continuations
-                }
-                // now add the detailed glyph entry.
-                glyphs.add_glyphs_for_byte_index(byte_idx, &datas);
-            }
-
-            glyph_span.start = glyph_span.end;
-            byte_range.start = byte_range.end;
-        }
-
-        // this must be called after adding all glyph data; it sorts the
-        // lookup table for finding detailed glyphs by associated char index.
-        glyphs.finalize_changes();
-    }
-
-    pub fn baseline(&self) -> Option<FontBaseline> {
-        unsafe { (*self.font).table_for_tag(BASE)? };
-
-        let mut hanging_baseline = 0;
-        let mut alphabetic_baseline = 0;
-        let mut ideographic_baseline = 0;
-
-        unsafe {
-            hb_ot_layout_get_baseline(
-                self.hb_font,
-                HB_OT_LAYOUT_BASELINE_TAG_ROMAN,
-                HB_DIRECTION_LTR,
-                HB_OT_TAG_DEFAULT_SCRIPT,
-                HB_OT_TAG_DEFAULT_LANGUAGE,
-                &mut alphabetic_baseline as *mut _,
-            );
-
-            hb_ot_layout_get_baseline(
-                self.hb_font,
-                HB_OT_LAYOUT_BASELINE_TAG_HANGING,
-                HB_DIRECTION_LTR,
-                HB_OT_TAG_DEFAULT_SCRIPT,
-                HB_OT_TAG_DEFAULT_LANGUAGE,
-                &mut hanging_baseline as *mut _,
-            );
-
-            hb_ot_layout_get_baseline(
-                self.hb_font,
-                HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
-                HB_DIRECTION_LTR,
-                HB_OT_TAG_DEFAULT_SCRIPT,
-                HB_OT_TAG_DEFAULT_LANGUAGE,
-                &mut ideographic_baseline as *mut _,
-            );
-        }
-
-        Some(FontBaseline {
-            ideographic_baseline: Shaper::fixed_to_float(ideographic_baseline) as f32,
-            alphabetic_baseline: Shaper::fixed_to_float(alphabetic_baseline) as f32,
-            hanging_baseline: Shaper::fixed_to_float(hanging_baseline) as f32,
-        })
-    }
-}
-
-/// Callbacks from Harfbuzz when font map and glyph advance lookup needed.
-struct FontFuncs(*mut hb_font_funcs_t);
-
-unsafe impl Sync for FontFuncs {}
-unsafe impl Send for FontFuncs {}
-
-static HB_FONT_FUNCS: LazyLock<FontFuncs> = LazyLock::new(|| unsafe {
-    let hb_funcs = hb_font_funcs_create();
-    hb_font_funcs_set_nominal_glyph_func(hb_funcs, Some(glyph_func), ptr::null_mut(), None);
-    hb_font_funcs_set_glyph_h_advance_func(
-        hb_funcs,
-        Some(glyph_h_advance_func),
-        ptr::null_mut(),
-        None,
-    );
-
-    FontFuncs(hb_funcs)
-});
-
-extern "C" fn glyph_func(
-    _: *mut hb_font_t,
-    font_data: *mut c_void,
-    unicode: hb_codepoint_t,
-    glyph: *mut hb_codepoint_t,
-    _: *mut c_void,
-) -> hb_bool_t {
-    let font: *const Font = font_data as *const Font;
-    assert!(!font.is_null());
-
-    match unsafe { (*font).glyph_index(char::from_u32(unicode).unwrap()) } {
-        Some(g) => {
-            unsafe { *glyph = g as hb_codepoint_t };
-            true as hb_bool_t
-        },
-        None => false as hb_bool_t,
-    }
-}
-
-extern "C" fn glyph_h_advance_func(
-    _: *mut hb_font_t,
-    font_data: *mut c_void,
-    glyph: hb_codepoint_t,
-    _: *mut c_void,
-) -> hb_position_t {
-    let font: *mut Font = font_data as *mut Font;
-    assert!(!font.is_null());
-
-    let advance = unsafe { (*font).glyph_h_advance(glyph as GlyphId) };
-    Shaper::float_to_fixed(advance)
-}
-
-/// Callback to get a font table out of a font.
-extern "C" fn font_table_func(
-    _: *mut hb_face_t,
-    tag: hb_tag_t,
-    user_data: *mut c_void,
-) -> *mut hb_blob_t {
-    // NB: These asserts have security implications.
-    let font = user_data as *const Font;
-    assert!(!font.is_null());
-
-    // TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
-    let Some(font_table) = (unsafe { (*font).table_for_tag(tag as FontTableTag) }) else {
-        return ptr::null_mut();
-    };
-
-    // `Box::into_raw` intentionally leaks the FontTable so we don't destroy the buffer
-    // while HarfBuzz is using it.  When HarfBuzz is done with the buffer, it will pass
-    // this raw pointer back to `destroy_blob_func` which will deallocate the Box.
-    let font_table_ptr = Box::into_raw(Box::new(font_table));
-
-    let buf = unsafe { (*font_table_ptr).buffer() };
-    // HarfBuzz calls `destroy_blob_func` when the buffer is no longer needed.
-    let blob = unsafe {
-        hb_blob_create(
-            buf.as_ptr() as *const c_char,
-            buf.len() as c_uint,
-            HB_MEMORY_MODE_READONLY,
-            font_table_ptr as *mut c_void,
-            Some(destroy_blob_func),
-        )
-    };
-
-    assert!(!blob.is_null());
-    blob
-}
-
-extern "C" fn destroy_blob_func(font_table_ptr: *mut c_void) {
-    unsafe {
-        drop(Box::from_raw(font_table_ptr as *mut FontTable));
-    }
-}
--- a/components/fonts/shapers/harfbuzz.rs
+++ b/components/fonts/shapers/harfbuzz.rs
@@ -0,0 +1,404 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#![allow(unsafe_code)]
+
+use std::os::raw::{c_char, c_int, c_uint, c_void};
+use std::sync::LazyLock;
+use std::{char, ptr};
+
+use app_units::Au;
+use euclid::default::Point2D;
+// Eventually we would like the shaper to be pluggable, as many operating systems have their own
+// shapers. For now, however, HarfBuzz is a hard dependency.
+use harfbuzz_sys::{
+    HB_DIRECTION_LTR, HB_DIRECTION_RTL, HB_MEMORY_MODE_READONLY, HB_OT_LAYOUT_BASELINE_TAG_HANGING,
+    HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT, HB_OT_LAYOUT_BASELINE_TAG_ROMAN,
+    hb_blob_create, hb_blob_t, hb_bool_t, hb_buffer_add_utf8, hb_buffer_create, hb_buffer_destroy,
+    hb_buffer_get_glyph_infos, hb_buffer_get_glyph_positions, hb_buffer_get_length,
+    hb_buffer_set_direction, hb_buffer_set_script, hb_buffer_t, hb_codepoint_t,
+    hb_face_create_for_tables, hb_face_destroy, hb_face_t, hb_feature_t, hb_font_create,
+    hb_font_destroy, hb_font_funcs_create, hb_font_funcs_set_glyph_h_advance_func,
+    hb_font_funcs_set_nominal_glyph_func, hb_font_funcs_t, hb_font_set_funcs, hb_font_set_ppem,
+    hb_font_set_scale, hb_font_t, hb_glyph_info_t, hb_glyph_position_t, hb_ot_layout_get_baseline,
+    hb_position_t, hb_shape, hb_tag_t,
+};
+use num_traits::Zero;
+
+use super::{ShapedGlyphEntry, THarfShapedGlyphData, THarfShaper, unicode_to_hb_script};
+use crate::platform::font::FontTable;
+use crate::{
+    BASE, Font, FontBaseline, FontTableMethods, FontTableTag, GlyphId, KERN, LIGA, ShapingFlags,
+    ShapingOptions, fixed_to_float, float_to_fixed, ot_tag,
+};
+
+const HB_OT_TAG_DEFAULT_SCRIPT: u32 = ot_tag!('D', 'F', 'L', 'T');
+const HB_OT_TAG_DEFAULT_LANGUAGE: u32 = ot_tag!('d', 'f', 'l', 't');
+
+pub struct ShapedGlyphData {
+    count: usize,
+    buffer: *mut hb_buffer_t,
+    glyph_infos: *mut hb_glyph_info_t,
+    pos_infos: *mut hb_glyph_position_t,
+}
+
+impl ShapedGlyphData {
+    /// Create a new [`ShapedGlyphData`] from the given HarfBuzz buffer.
+    ///
+    /// # Safety
+    ///
+    /// - Passing an invalid buffer pointer to this function results in undefined behavior.
+    /// - This function takes ownership of the buffer and the ShapedGlyphData destroys the buffer when dropped
+    ///   so the pointer must an owned pointer and must not be used after being passed to this function
+    pub unsafe fn new(buffer: *mut hb_buffer_t) -> ShapedGlyphData {
+        let mut glyph_count = 0;
+        let glyph_infos = unsafe { hb_buffer_get_glyph_infos(buffer, &mut glyph_count) };
+        assert!(!glyph_infos.is_null());
+        let mut pos_count = 0;
+        let pos_infos = unsafe { hb_buffer_get_glyph_positions(buffer, &mut pos_count) };
+        assert!(!pos_infos.is_null());
+        assert_eq!(glyph_count, pos_count);
+
+        ShapedGlyphData {
+            count: glyph_count as usize,
+            buffer,
+            glyph_infos,
+            pos_infos,
+        }
+    }
+}
+
+impl Drop for ShapedGlyphData {
+    fn drop(&mut self) {
+        unsafe { hb_buffer_destroy(self.buffer) }
+    }
+}
+
+impl THarfShapedGlyphData for ShapedGlyphData {
+    #[inline]
+    fn len(&self) -> usize {
+        self.count
+    }
+
+    #[inline(always)]
+    fn byte_offset_of_glyph(&self, i: usize) -> usize {
+        assert!(i < self.count);
+
+        unsafe {
+            let glyph_info_i = self.glyph_infos.add(i);
+            (*glyph_info_i).cluster as usize
+        }
+    }
+
+    /// Returns shaped glyph data for one glyph, and updates the y-position of the pen.
+    fn entry_for_glyph(&self, i: usize, y_pos: &mut Au) -> ShapedGlyphEntry {
+        assert!(i < self.count);
+
+        unsafe {
+            let glyph_info_i = self.glyph_infos.add(i);
+            let pos_info_i = self.pos_infos.add(i);
+            let x_offset = Shaper::fixed_to_float((*pos_info_i).x_offset);
+            let y_offset = Shaper::fixed_to_float((*pos_info_i).y_offset);
+            let x_advance = Shaper::fixed_to_float((*pos_info_i).x_advance);
+            let y_advance = Shaper::fixed_to_float((*pos_info_i).y_advance);
+
+            let x_offset = Au::from_f64_px(x_offset);
+            let y_offset = Au::from_f64_px(y_offset);
+            let x_advance = Au::from_f64_px(x_advance);
+            let y_advance = Au::from_f64_px(y_advance);
+
+            let offset = if x_offset.is_zero() && y_offset.is_zero() && y_advance.is_zero() {
+                None
+            } else {
+                // adjust the pen..
+                if y_advance > Au::zero() {
+                    *y_pos -= y_advance;
+                }
+
+                Some(Point2D::new(x_offset, *y_pos - y_offset))
+            };
+
+            ShapedGlyphEntry {
+                codepoint: (*glyph_info_i).codepoint as GlyphId,
+                advance: x_advance,
+                offset,
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Shaper {
+    hb_face: *mut hb_face_t,
+    hb_font: *mut hb_font_t,
+    font: *const Font,
+}
+
+// The HarfBuzz API is thread safe as well as our `Font`, so we can make the data
+// structures here as thread-safe as well. This doesn't seem to be documented,
+// but was expressed as one of the original goals of the HarfBuzz API.
+unsafe impl Sync for Shaper {}
+unsafe impl Send for Shaper {}
+
+impl Drop for Shaper {
+    fn drop(&mut self) {
+        unsafe {
+            assert!(!self.hb_face.is_null());
+            hb_face_destroy(self.hb_face);
+
+            assert!(!self.hb_font.is_null());
+            hb_font_destroy(self.hb_font);
+        }
+    }
+}
+
+impl Shaper {
+    #[allow(clippy::not_unsafe_ptr_arg_deref)] // Has an unsafe block inside
+    pub fn new(font: &Font) -> Shaper {
+        let font = font as *const Font;
+        unsafe {
+            let hb_face: *mut hb_face_t = hb_face_create_for_tables(
+                Some(font_table_func),
+                font as *const c_void as *mut c_void,
+                None,
+            );
+            let hb_font: *mut hb_font_t = hb_font_create(hb_face);
+
+            // Set points-per-em. if zero, performs no hinting in that direction.
+            let pt_size = (*font).descriptor.pt_size.to_f64_px();
+            hb_font_set_ppem(hb_font, pt_size as c_uint, pt_size as c_uint);
+
+            // Set scaling. Note that this takes 16.16 fixed point.
+            hb_font_set_scale(
+                hb_font,
+                Shaper::float_to_fixed(pt_size) as c_int,
+                Shaper::float_to_fixed(pt_size) as c_int,
+            );
+
+            // configure static function callbacks.
+            hb_font_set_funcs(
+                hb_font,
+                HB_FONT_FUNCS.0,
+                font as *mut Font as *mut c_void,
+                None,
+            );
+
+            Shaper {
+                hb_face,
+                hb_font,
+                font,
+            }
+        }
+    }
+
+    fn float_to_fixed(f: f64) -> i32 {
+        float_to_fixed(16, f)
+    }
+
+    fn fixed_to_float(i: hb_position_t) -> f64 {
+        fixed_to_float(16, i)
+    }
+}
+
+impl THarfShaper for Shaper {
+    type ShapedGlyphData = ShapedGlyphData;
+
+    /// Calculate the layout metrics associated with the given text when painted in a specific font.
+    fn shape_text(&self, text: &str, options: &ShapingOptions) -> Self::ShapedGlyphData {
+        unsafe {
+            let hb_buffer: *mut hb_buffer_t = hb_buffer_create();
+            hb_buffer_set_direction(
+                hb_buffer,
+                if options.flags.contains(ShapingFlags::RTL_FLAG) {
+                    HB_DIRECTION_RTL
+                } else {
+                    HB_DIRECTION_LTR
+                },
+            );
+
+            hb_buffer_set_script(hb_buffer, unicode_to_hb_script(options.script));
+
+            hb_buffer_add_utf8(
+                hb_buffer,
+                text.as_ptr() as *const c_char,
+                text.len() as c_int,
+                0,
+                text.len() as c_int,
+            );
+
+            let mut features = Vec::new();
+            if options
+                .flags
+                .contains(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG)
+            {
+                features.push(hb_feature_t {
+                    tag: LIGA,
+                    value: 0,
+                    start: 0,
+                    end: hb_buffer_get_length(hb_buffer),
+                })
+            }
+            if options
+                .flags
+                .contains(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
+            {
+                features.push(hb_feature_t {
+                    tag: KERN,
+                    value: 0,
+                    start: 0,
+                    end: hb_buffer_get_length(hb_buffer),
+                })
+            }
+
+            hb_shape(
+                self.hb_font,
+                hb_buffer,
+                features.as_mut_ptr(),
+                features.len() as u32,
+            );
+
+            ShapedGlyphData::new(hb_buffer)
+        }
+    }
+
+    fn font(&self) -> &Font {
+        unsafe { &(*self.font) }
+    }
+
+    fn baseline(&self) -> Option<FontBaseline> {
+        unsafe { (*self.font).table_for_tag(BASE)? };
+
+        let mut hanging_baseline = 0;
+        let mut alphabetic_baseline = 0;
+        let mut ideographic_baseline = 0;
+
+        unsafe {
+            hb_ot_layout_get_baseline(
+                self.hb_font,
+                HB_OT_LAYOUT_BASELINE_TAG_ROMAN,
+                HB_DIRECTION_LTR,
+                HB_OT_TAG_DEFAULT_SCRIPT,
+                HB_OT_TAG_DEFAULT_LANGUAGE,
+                &mut alphabetic_baseline as *mut _,
+            );
+
+            hb_ot_layout_get_baseline(
+                self.hb_font,
+                HB_OT_LAYOUT_BASELINE_TAG_HANGING,
+                HB_DIRECTION_LTR,
+                HB_OT_TAG_DEFAULT_SCRIPT,
+                HB_OT_TAG_DEFAULT_LANGUAGE,
+                &mut hanging_baseline as *mut _,
+            );
+
+            hb_ot_layout_get_baseline(
+                self.hb_font,
+                HB_OT_LAYOUT_BASELINE_TAG_IDEO_EMBOX_BOTTOM_OR_LEFT,
+                HB_DIRECTION_LTR,
+                HB_OT_TAG_DEFAULT_SCRIPT,
+                HB_OT_TAG_DEFAULT_LANGUAGE,
+                &mut ideographic_baseline as *mut _,
+            );
+        }
+
+        Some(FontBaseline {
+            ideographic_baseline: Shaper::fixed_to_float(ideographic_baseline) as f32,
+            alphabetic_baseline: Shaper::fixed_to_float(alphabetic_baseline) as f32,
+            hanging_baseline: Shaper::fixed_to_float(hanging_baseline) as f32,
+        })
+    }
+}
+
+/// Callbacks from Harfbuzz when font map and glyph advance lookup needed.
+struct FontFuncs(*mut hb_font_funcs_t);
+
+unsafe impl Sync for FontFuncs {}
+unsafe impl Send for FontFuncs {}
+
+static HB_FONT_FUNCS: LazyLock<FontFuncs> = LazyLock::new(|| unsafe {
+    let hb_funcs = hb_font_funcs_create();
+    hb_font_funcs_set_nominal_glyph_func(hb_funcs, Some(glyph_func), ptr::null_mut(), None);
+    hb_font_funcs_set_glyph_h_advance_func(
+        hb_funcs,
+        Some(glyph_h_advance_func),
+        ptr::null_mut(),
+        None,
+    );
+
+    FontFuncs(hb_funcs)
+});
+
+extern "C" fn glyph_func(
+    _: *mut hb_font_t,
+    font_data: *mut c_void,
+    unicode: hb_codepoint_t,
+    glyph: *mut hb_codepoint_t,
+    _: *mut c_void,
+) -> hb_bool_t {
+    let font: *const Font = font_data as *const Font;
+    assert!(!font.is_null());
+
+    match unsafe { (*font).glyph_index(char::from_u32(unicode).unwrap()) } {
+        Some(g) => {
+            unsafe { *glyph = g as hb_codepoint_t };
+            true as hb_bool_t
+        },
+        None => false as hb_bool_t,
+    }
+}
+
+extern "C" fn glyph_h_advance_func(
+    _: *mut hb_font_t,
+    font_data: *mut c_void,
+    glyph: hb_codepoint_t,
+    _: *mut c_void,
+) -> hb_position_t {
+    let font: *mut Font = font_data as *mut Font;
+    assert!(!font.is_null());
+
+    let advance = unsafe { (*font).glyph_h_advance(glyph as GlyphId) };
+    Shaper::float_to_fixed(advance)
+}
+
+/// Callback to get a font table out of a font.
+extern "C" fn font_table_func(
+    _: *mut hb_face_t,
+    tag: hb_tag_t,
+    user_data: *mut c_void,
+) -> *mut hb_blob_t {
+    // NB: These asserts have security implications.
+    let font = user_data as *const Font;
+    assert!(!font.is_null());
+
+    // TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
+    let Some(font_table) = (unsafe { (*font).table_for_tag(tag as FontTableTag) }) else {
+        return ptr::null_mut();
+    };
+
+    // `Box::into_raw` intentionally leaks the FontTable so we don't destroy the buffer
+    // while HarfBuzz is using it.  When HarfBuzz is done with the buffer, it will pass
+    // this raw pointer back to `destroy_blob_func` which will deallocate the Box.
+    let font_table_ptr = Box::into_raw(Box::new(font_table));
+
+    let buf = unsafe { (*font_table_ptr).buffer() };
+    // HarfBuzz calls `destroy_blob_func` when the buffer is no longer needed.
+    let blob = unsafe {
+        hb_blob_create(
+            buf.as_ptr() as *const c_char,
+            buf.len() as c_uint,
+            HB_MEMORY_MODE_READONLY,
+            font_table_ptr as *mut c_void,
+            Some(destroy_blob_func),
+        )
+    };
+
+    assert!(!blob.is_null());
+    blob
+}
+
+extern "C" fn destroy_blob_func(font_table_ptr: *mut c_void) {
+    unsafe {
+        drop(Box::from_raw(font_table_ptr as *mut FontTable));
+    }
+}
--- a/components/fonts/shapers/harfrust.rs
+++ b/components/fonts/shapers/harfrust.rs
@@ -0,0 +1,167 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use app_units::Au;
+use euclid::default::Point2D;
+use harfrust::{
+    Feature, FontRef as HarfRustFontRef, GlyphBuffer, Script, ShaperData, Tag, UnicodeBuffer,
+};
+use num_traits::Zero as _;
+use read_fonts::TableProvider;
+use smallvec::SmallVec;
+
+use super::{ShapedGlyphEntry, THarfShapedGlyphData, THarfShaper, unicode_to_hb_script};
+use crate::{Font, FontData, ShapingFlags};
+
+pub struct ShapedGlyphData {
+    data: GlyphBuffer,
+    scale: f64,
+}
+
+impl THarfShapedGlyphData for ShapedGlyphData {
+    fn len(&self) -> usize {
+        self.data.len()
+    }
+
+    fn byte_offset_of_glyph(&self, i: usize) -> usize {
+        self.data.glyph_infos()[i].cluster as usize
+    }
+
+    fn entry_for_glyph(&self, i: usize, y_pos: &mut app_units::Au) -> super::ShapedGlyphEntry {
+        let glyph_info_i = self.data.glyph_infos()[i];
+        let pos_info_i = self.data.glyph_positions()[i];
+        let x_offset = Au::from_f64_px(pos_info_i.x_offset as f64 * self.scale);
+        let y_offset = Au::from_f64_px(pos_info_i.y_offset as f64 * self.scale);
+        let x_advance = Au::from_f64_px(pos_info_i.x_advance as f64 * self.scale);
+        let y_advance = Au::from_f64_px(pos_info_i.y_advance as f64 * self.scale);
+
+        let offset = if x_offset.is_zero() && y_offset.is_zero() && y_advance.is_zero() {
+            None
+        } else {
+            // adjust the pen..
+            if y_advance > Au::zero() {
+                *y_pos -= y_advance;
+            }
+
+            Some(Point2D::new(x_offset, *y_pos - y_offset))
+        };
+
+        ShapedGlyphEntry {
+            codepoint: glyph_info_i.glyph_id,
+            advance: x_advance,
+            offset,
+        }
+    }
+}
+
+pub struct Shaper {
+    font: *const Font,
+    /// The raw byte data of the font
+    font_data: FontData,
+    /// The index of a font in it's collection (.ttc)
+    /// If the font file is not a collection then this is 0
+    font_index: u32,
+    // Used for scaling HarfRust's output
+    scale: f64,
+    ppem: f64,
+}
+
+// `Font` and `FontData` are both threadsafe, so we can make the data structures here as thread-safe as well.
+#[allow(unsafe_code)]
+unsafe impl Sync for Shaper {}
+#[allow(unsafe_code)]
+unsafe impl Send for Shaper {}
+
+impl Shaper {
+    pub(crate) fn new(font: &Font) -> Self {
+        let raw_font = font.raw_font();
+        let font_data = raw_font.data.clone();
+        let font_index = raw_font.index;
+        // Set points-per-em. if zero, performs no hinting in that direction
+        let ppem = font.descriptor.pt_size.to_f64_px();
+        let font_ref = read_fonts::FontRef::from_index(font_data.as_ref(), font_index).unwrap();
+        let units_per_em = font_ref.head().unwrap().units_per_em();
+        let scale = ppem / (units_per_em as f64);
+        Self {
+            font: font as *const Font,
+            font_data,
+            font_index,
+            scale,
+            ppem,
+        }
+    }
+}
+
+impl THarfShaper for Shaper {
+    type ShapedGlyphData = ShapedGlyphData;
+
+    fn shape_text(&self, text: &str, options: &crate::ShapingOptions) -> ShapedGlyphData {
+        let mut buffer = UnicodeBuffer::new();
+
+        // Set direction
+        buffer.set_direction(if options.flags.contains(ShapingFlags::RTL_FLAG) {
+            harfrust::Direction::RightToLeft
+        } else {
+            harfrust::Direction::LeftToRight
+        });
+
+        // Set script
+        let script =
+            Script::from_iso15924_tag(Tag::from_u32(unicode_to_hb_script(options.script))).unwrap();
+        buffer.set_script(script);
+
+        // Push text
+        buffer.push_str(text);
+
+        // Features
+        let mut features = SmallVec::<[Feature; 2]>::new();
+        if options
+            .flags
+            .contains(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG)
+        {
+            features.push(Feature::new(Tag::new(b"liga"), 0, ..));
+        }
+        if options
+            .flags
+            .contains(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
+        {
+            features.push(Feature::new(Tag::new(b"kern"), 0, ..));
+        }
+
+        let hr_font =
+            HarfRustFontRef::from_index(self.font_data.as_ref(), self.font_index).unwrap();
+        let shaper_data = ShaperData::new(&hr_font);
+
+        // TODO: handle font variations
+        // let variations: Vec<Variation> = Vec::new();
+        // let instance_data = ShaperInstance::from_variations(&hr_font, &variations);
+
+        let shaper = shaper_data
+            .shaper(&hr_font)
+            // Set the instance
+            // .instance(Some(&instance_data))
+            .build();
+        let glyph_buffer = shaper.shape(buffer, &features);
+
+        ShapedGlyphData {
+            data: glyph_buffer,
+            scale: self.scale,
+        }
+    }
+
+    #[allow(unsafe_code)]
+    fn font(&self) -> &Font {
+        // SAFETY: the font actually owns this shaper so it cannot have been dropped
+        unsafe { &(*self.font) }
+    }
+
+    fn baseline(&self) -> Option<crate::FontBaseline> {
+        // TODO: Implement baseline extraction
+        Some(crate::FontBaseline {
+            ideographic_baseline: self.ppem as f32,
+            alphabetic_baseline: self.ppem as f32,
+            hanging_baseline: self.ppem as f32,
+        })
+    }
+}
--- a/components/fonts/shapers/mod.rs
+++ b/components/fonts/shapers/mod.rs
@@ -0,0 +1,245 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use std::cmp;
+
+use app_units::Au;
+use base::text::is_bidi_control;
+use euclid::default::Point2D;
+use fonts_traits::ByteIndex;
+use log::debug;
+use num_traits::Zero as _;
+
+use crate::{
+    Font, FontBaseline, GlyphData, GlyphId, GlyphStore, ShapingOptions, advance_for_shaped_glyph,
+};
+
+#[cfg(feature = "harfbuzz")]
+mod harfbuzz;
+#[cfg(feature = "harfbuzz")]
+pub use harfbuzz::{ShapedGlyphData, Shaper};
+
+#[cfg(feature = "harfrust")]
+mod harfrust;
+#[cfg(feature = "harfrust")]
+pub use harfrust::{ShapedGlyphData, Shaper};
+
+const NO_GLYPH: i32 = -1;
+
+/// Utility function to convert a `unicode_script::Script` enum into the corresponding `c_uint` tag that
+/// harfbuzz uses to represent unicode scipts.
+fn unicode_to_hb_script(script: unicode_script::Script) -> core::ffi::c_uint {
+    let bytes: [u8; 4] = match script {
+        unicode_script::Script::Unknown => *b"Zzzz",
+        _ => {
+            let short_name = script.short_name();
+            short_name.as_bytes().try_into().unwrap()
+        },
+    };
+
+    u32::from_be_bytes(bytes) as core::ffi::c_uint
+}
+
+struct ShapedGlyphEntry {
+    codepoint: GlyphId,
+    advance: Au,
+    offset: Option<Point2D<Au>>,
+}
+
+/// A servo shaper
+pub(crate) trait TShaper: Send + Sync {
+    /// Calculate the layout metrics associated with the given text when painted in a specific font.
+    fn shape_text(&self, text: &str, options: &ShapingOptions, glyphs: &mut GlyphStore);
+    fn baseline(&self) -> Option<FontBaseline>;
+}
+
+/// Holds the results of shaping. Abstracts over HarfBuzz and HarfRust which return data in very similar
+/// form but with different types
+trait THarfShapedGlyphData {
+    /// The number of shaped glyphs
+    fn len(&self) -> usize;
+    /// The byte offset of the shaped glyph in the souce text
+    fn byte_offset_of_glyph(&self, i: usize) -> usize;
+    /// Returns shaped glyph data for one glyph, and updates the y-position of the pen.
+    fn entry_for_glyph(&self, i: usize, y_pos: &mut Au) -> ShapedGlyphEntry;
+}
+
+/// A Servo shaper based on HarfBuzz (HarfBuzz or HarfRust)
+trait THarfShaper: Send + Sync {
+    type ShapedGlyphData: THarfShapedGlyphData;
+    fn shape_text(&self, text: &str, options: &ShapingOptions) -> ShapedGlyphData;
+    fn font(&self) -> &Font;
+    fn baseline(&self) -> Option<FontBaseline>;
+}
+
+impl<T: THarfShaper> TShaper for T {
+    fn baseline(&self) -> Option<FontBaseline> {
+        THarfShaper::baseline(self)
+    }
+
+    fn shape_text(&self, text: &str, options: &ShapingOptions, glyphs: &mut GlyphStore) {
+        let glyph_data = self.shape_text(text, options);
+        let glyph_count = glyph_data.len();
+        let byte_max = text.len();
+
+        debug!(
+            "Shaped text[byte count={}], got back {} glyph info records.",
+            byte_max, glyph_count
+        );
+
+        // make map of what chars have glyphs
+        let mut byte_to_glyph = vec![NO_GLYPH; byte_max];
+
+        debug!("(glyph idx) -> (text byte offset)");
+        for i in 0..glyph_data.len() {
+            let loc = glyph_data.byte_offset_of_glyph(i);
+            if loc < byte_max {
+                byte_to_glyph[loc] = i as i32;
+            } else {
+                debug!(
+                    "ERROR: tried to set out of range byte_to_glyph: idx={}, glyph idx={}",
+                    loc, i
+                );
+            }
+            debug!("{} -> {}", i, loc);
+        }
+
+        debug!("text: {:?}", text);
+        debug!("(char idx): char->(glyph index):");
+        for (i, ch) in text.char_indices() {
+            debug!("{}: {:?} --> {}", i, ch, byte_to_glyph[i]);
+        }
+
+        let mut glyph_span = 0..0;
+        let mut byte_range = 0..0;
+
+        let mut y_pos = Au::zero();
+
+        // main loop over each glyph. each iteration usually processes 1 glyph and 1+ chars.
+        // in cases with complex glyph-character associations, 2+ glyphs and 1+ chars can be
+        // processed.
+        while glyph_span.start < glyph_count {
+            debug!("Processing glyph at idx={}", glyph_span.start);
+            glyph_span.end = glyph_span.start;
+            byte_range.end = glyph_data.byte_offset_of_glyph(glyph_span.start);
+
+            while byte_range.end < byte_max {
+                byte_range.end += 1;
+                // Extend the byte range to include any following byte without its own glyph.
+                while byte_range.end < byte_max && byte_to_glyph[byte_range.end] == NO_GLYPH {
+                    byte_range.end += 1;
+                }
+
+                // Extend the glyph range to include all glyphs covered by bytes processed so far.
+                let mut max_glyph_idx = glyph_span.end;
+                for glyph_idx in &byte_to_glyph[byte_range.clone()] {
+                    if *glyph_idx != NO_GLYPH {
+                        max_glyph_idx = cmp::max(*glyph_idx as usize + 1, max_glyph_idx);
+                    }
+                }
+                if max_glyph_idx > glyph_span.end {
+                    glyph_span.end = max_glyph_idx;
+                    debug!("Extended glyph span to {:?}", glyph_span);
+                }
+
+                // if there's just one glyph, then we don't need further checks.
+                if glyph_span.len() == 1 {
+                    break;
+                }
+
+                // if no glyphs were found yet, extend the char byte range more.
+                if glyph_span.is_empty() {
+                    continue;
+                }
+
+                // If byte_range now includes all the byte offsets found in glyph_span, then we
+                // have found a contiguous "cluster" and can stop extending it.
+                let mut all_glyphs_are_within_cluster: bool = true;
+                for j in glyph_span.clone() {
+                    let loc = glyph_data.byte_offset_of_glyph(j);
+                    if !(byte_range.start <= loc && loc < byte_range.end) {
+                        all_glyphs_are_within_cluster = false;
+                        break;
+                    }
+                }
+                if all_glyphs_are_within_cluster {
+                    break;
+                }
+
+                // Otherwise, the bytes we have seen so far correspond to a non-contiguous set of
+                // glyphs.  Keep extending byte_range until we fill in all the holes in the glyph
+                // span or reach the end of the text.
+            }
+
+            assert!(!byte_range.is_empty());
+            assert!(!glyph_span.is_empty());
+
+            // Now byte_range is the ligature clump formed by the glyphs in glyph_span.
+            // We will save these glyphs to the glyph store at the index of the first byte.
+            let byte_idx = ByteIndex(byte_range.start as isize);
+
+            if glyph_span.len() == 1 {
+                // Fast path: 1-to-1 mapping of byte offset to single glyph.
+                //
+                // TODO(Issue #214): cluster ranges need to be computed before
+                // shaping, and then consulted here.
+                // for now, just pretend that every character is a cluster start.
+                // (i.e., pretend there are no combining character sequences).
+                // 1-to-1 mapping of character to glyph also treated as ligature start.
+                //
+                // NB: When we acquire the ability to handle ligatures that cross word boundaries,
+                // we'll need to do something special to handle `word-spacing` properly.
+                let character = text[byte_range.clone()].chars().next().unwrap();
+                if is_bidi_control(character) {
+                    // Don't add any glyphs for bidi control chars
+                } else {
+                    let (glyph_id, advance, offset) = if character == '\t' {
+                        // Treat tabs in pre-formatted text as a fixed number of spaces. The glyph id does
+                        // not matter here as Servo doesn't render any glyphs for whitespace.
+                        //
+                        // TODO: Proper tab stops. This should happen in layout and be based on the
+                        // size of the space character of the inline formatting context.
+                        let font = self.font();
+                        (
+                            font.glyph_index(' ').unwrap_or(0),
+                            font.metrics.space_advance * 8,
+                            Default::default(),
+                        )
+                    } else {
+                        let shape = glyph_data.entry_for_glyph(glyph_span.start, &mut y_pos);
+                        let advance = advance_for_shaped_glyph(shape.advance, character, options);
+                        (shape.codepoint, advance, shape.offset)
+                    };
+
+                    let data = GlyphData::new(glyph_id, advance, offset, true, true);
+                    glyphs.add_glyph_for_byte_index(byte_idx, character, &data);
+                }
+            } else {
+                // collect all glyphs to be assigned to the first character.
+                let mut datas = vec![];
+
+                for glyph_i in glyph_span.clone() {
+                    let shape = glyph_data.entry_for_glyph(glyph_i, &mut y_pos);
+                    datas.push(GlyphData::new(
+                        shape.codepoint,
+                        shape.advance,
+                        shape.offset,
+                        true, // treat as cluster start
+                        glyph_i > glyph_span.start,
+                    ));
+                    // all but first are ligature continuations
+                }
+                // now add the detailed glyph entry.
+                glyphs.add_glyphs_for_byte_index(byte_idx, &datas);
+            }
+
+            glyph_span.start = glyph_span.end;
+            byte_range.start = byte_range.end;
+        }
+
+        // this must be called after adding all glyph data; it sorts the
+        // lookup table for finding detailed glyphs by associated char index.
+        glyphs.finalize_changes();
+    }
+}
Author	SHA1	Message	Date
Nico Burns	873a23ead1	Use WebRender with fontations backend Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-17 19:24:38 +01:00
Nico Burns	0b55d6cbb3	Fix .ttc files on macos Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-17 14:49:15 +01:00
Nico Burns	044596ee71	Fixup scaling Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 23:40:39 +01:00
Nico Burns	e8b79d0458	Fix license headers Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 15:55:59 +01:00
Nico Burns	4de78b26f7	Don't set point_size on the shaper Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 14:23:44 +01:00
Nico Burns	9b2f50c151	harfrust: handle scaling Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 13:49:06 +01:00
Nico Burns	4669f24c4f	Implement HarfRust shaping backend Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 13:49:06 +01:00
Nico Burns	ab83b08663	Add harfrust dep + upgrade skrifa and read-fonts Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 13:49:06 +01:00
Nico Burns	c1a6900286	Add Harf-shaper specific abstractions Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 13:49:06 +01:00
Nico Burns	abe58c575a	Move harfbuzz shaper to a new shapers module Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 02:54:33 +01:00
Nico Burns	e6bb7753c4	Use built-in conversion function from unicode_script to convert script for harfbuzz Signed-off-by: Nico Burns <nico@nicoburns.com>	2025-08-16 02:54:32 +01:00