diff --git a/crates/canvas/Cargo.toml b/crates/canvas/Cargo.toml
index a73d0b670249dd67faba67f2095dbd1bd5134b49..0bfc76a723b64c0a23baafca804be0f69bea8f86 100644
--- a/crates/canvas/Cargo.toml
+++ b/crates/canvas/Cargo.toml
@@ -18,6 +18,7 @@ parley.workspace = true
 serde = { version = "1.0.229", features = ["derive"] }
 serde_json = "1.0.151"
 icu_normalizer = "2.3"
+miniz_oxide = "0.8"
 skrifa = "0.44.0"
 # std's clock where there is one; the browser's on wasm32-unknown-unknown, whose std has none.
 web-time = "1.1"
@@ -39,11 +40,13 @@ path = "src/bin/page_probe.rs"
 
 [dev-dependencies]
 draw = { path = "../draw", features = ["wgpu"] }
-miniz_oxide = "0.8"
 accesskit_consumer = "0.39.0"
 pollster = "0.4"
 wgpu.workspace = true
 
+[build-dependencies]
+miniz_oxide = "0.8"
+
 [[example]]
 name = "render_page"
 required-features = ["gpu"]
diff --git a/crates/canvas/build.rs b/crates/canvas/build.rs
new file mode 100644
index 0000000000000000000000000000000000000000..66fb802fe25c7bc805d42d038c7b89468a0438c7
--- /dev/null
+++ b/crates/canvas/build.rs
@@ -0,0 +1,71 @@
+//! Deflates the font clones the target embeds into `bundled.rs`, a table `layout.rs` includes,
+//! leaving out each whose family the target's system ships.
+
+/// Metric-compatible clones, by the family each stands in for.
+const CLONES: [(&str, &[&str]); 4] = [
+    (
+        "Calibri",
+        &[
+            "Carlito-Regular",
+            "Carlito-Bold",
+            "Carlito-Italic",
+            "Carlito-BoldItalic",
+        ],
+    ),
+    ("Arial", &["Arimo", "Arimo-Italic"]),
+    (
+        "Times New Roman",
+        &[
+            "Tinos-Regular",
+            "Tinos-Bold",
+            "Tinos-Italic",
+            "Tinos-BoldItalic",
+        ],
+    ),
+    (
+        "Courier New",
+        &[
+            "Cousine-Regular",
+            "Cousine-Bold",
+            "Cousine-Italic",
+            "Cousine-BoldItalic",
+        ],
+    ),
+];
+
+fn main() {
+    println!("cargo::rerun-if-changed=build.rs");
+    println!("cargo::rerun-if-changed=assets/fonts");
+    let os = std::env::var("CARGO_CFG_TARGET_OS").unwrap();
+    let browser = std::env::var("CARGO_CFG_TARGET_ARCH").unwrap() == "wasm32";
+    let out = std::path::PathBuf::from(std::env::var_os("OUT_DIR").unwrap());
+    let mut table = String::from("&[\n");
+    for (family, faces) in CLONES {
+        // The browser fetches them beside the module instead.
+        let shipped = browser
+            || match os.as_str() {
+                "windows" => true,
+                "macos" | "ios" => family != "Calibri",
+                _ => false,
+            };
+        if shipped {
+            continue;
+        }
+        table += &format!("    ({family:?}, &[\n");
+        for face in faces {
+            let font = std::fs::read(format!("assets/fonts/{face}.ttf")).unwrap();
+            let deflated = format!("{face}.ttf.deflate");
+            std::fs::write(
+                out.join(&deflated),
+                miniz_oxide::deflate::compress_to_vec(&font, 10),
+            )
+            .unwrap();
+            // Relative to OUT_DIR, so a target folder reached by another path still finds them.
+            table +=
+                &format!("        include_bytes!(concat!(env!(\"OUT_DIR\"), \"/{deflated}\")),\n");
+        }
+        table += "    ]),\n";
+    }
+    table += "]\n";
+    std::fs::write(out.join("bundled.rs"), table).unwrap();
+}
diff --git a/crates/canvas/src/layout.rs b/crates/canvas/src/layout.rs
index 8ccc0d142788d356f5b18f759c379513c21571c8..32dd575984df69355992d084f63f7a756df42829 100644
--- a/crates/canvas/src/layout.rs
+++ b/crates/canvas/src/layout.rs
@@ -12,7 +12,7 @@ use std::{
     fmt,
     ops::Range,
     sync::{
-        Arc,
+        Arc, OnceLock,
         atomic::{AtomicU64, Ordering},
     },
 };
@@ -113,55 +113,18 @@ pub(crate) const DEFAULT_FONT: &str = "Arial";
 pub(crate) const DEFAULT_FONT_SIZE: f32 = 11.0;
 
 /// Metric-compatible faces for the fonts OneNote pages use most, under the SIL Open Font
-/// Licence files beside them, by the family each stands in for. Each is left out where the
-/// system ships the family it stands in for: Windows ships all four, macOS and iOS all but
-/// Calibri. The browser fetches them beside the module instead (`register_substitute`),
-/// keeping them out of it.
-#[cfg(not(any(windows, target_arch = "wasm32")))]
-const BUNDLED: &[(&str, &[&[u8]])] = &[
-    (
-        "Calibri",
-        &[
-            include_bytes!("../assets/fonts/Carlito-Regular.ttf"),
-            include_bytes!("../assets/fonts/Carlito-Bold.ttf"),
-            include_bytes!("../assets/fonts/Carlito-Italic.ttf"),
-            include_bytes!("../assets/fonts/Carlito-BoldItalic.ttf"),
-        ],
-    ),
-    #[cfg(not(any(target_os = "macos", target_os = "ios")))]
-    (
-        "Arial",
-        &[
-            include_bytes!("../assets/fonts/Arimo.ttf"),
-            include_bytes!("../assets/fonts/Arimo-Italic.ttf"),
-        ],
-    ),
-    #[cfg(not(any(target_os = "macos", target_os = "ios")))]
-    (
-        "Times New Roman",
-        &[
-            include_bytes!("../assets/fonts/Tinos-Regular.ttf"),
-            include_bytes!("../assets/fonts/Tinos-Bold.ttf"),
-            include_bytes!("../assets/fonts/Tinos-Italic.ttf"),
-            include_bytes!("../assets/fonts/Tinos-BoldItalic.ttf"),
-        ],
-    ),
-    #[cfg(not(any(target_os = "macos", target_os = "ios")))]
-    (
-        "Courier New",
-        &[
-            include_bytes!("../assets/fonts/Cousine-Regular.ttf"),
-            include_bytes!("../assets/fonts/Cousine-Bold.ttf"),
-            include_bytes!("../assets/fonts/Cousine-Italic.ttf"),
-            include_bytes!("../assets/fonts/Cousine-BoldItalic.ttf"),
-        ],
-    ),
-];
+/// Licence files beside them, deflated, by the family each stands in for. The build script
+/// leaves out each whose family the system ships, and every one from the browser's module,
+/// which fetches them beside it instead (`register_substitute`).
+const BUNDLED: &[(&str, &[&[u8]])] = include!(concat!(env!("OUT_DIR"), "/bundled.rs"));
+
+/// Each bundled family's faces, inflated the first time an engine lacks the family.
+static INFLATED: [OnceLock<Vec<Blob<u8>>>; BUNDLED.len()] =
+    [const { OnceLock::new() }; BUNDLED.len()];
 
 impl Default for TextEngine {
     /// An engine that lays out each bundled family in its substitute where it is missing.
     fn default() -> Self {
-        #[cfg_attr(any(windows, target_arch = "wasm32"), allow(unused_mut))]
         let mut engine = Self {
             // Clones share loaded font files, so glyphs one lays out draw from the same cache.
             fonts: FontContext {
@@ -172,14 +135,23 @@ impl Default for TextEngine {
             arial_substitutes: BTreeSet::new(),
             substitutes: BTreeMap::new(),
         };
-        #[cfg(not(any(windows, target_arch = "wasm32")))]
-        for &(family, faces) in BUNDLED {
-            if engine.fonts.collection.family_id(family).is_none() {
-                for face in faces {
-                    engine
-                        .register(Blob::new(Arc::new(*face)), true)
-                        .expect("bundled substitutes register");
-                }
+        for (&(family, faces), inflated) in BUNDLED.iter().zip(&INFLATED) {
+            if engine.fonts.collection.family_id(family).is_some() {
+                continue;
+            }
+            let faces = inflated.get_or_init(|| {
+                faces
+                    .iter()
+                    .map(|face| {
+                        let face = miniz_oxide::inflate::decompress_to_vec(face);
+                        Blob::new(Arc::new(face.expect("bundled substitutes inflate")))
+                    })
+                    .collect()
+            });
+            for face in faces {
+                engine
+                    .register(face.clone(), true)
+                    .expect("bundled substitutes register");
             }
         }
         engine