Merge pull request #14029 from horizon-rust/layers/client-lib-style

🤖 Agent: ui_theme's palette, sizes and Geist fonts come from menu_style; with no fonts given (NEUTRAL) the Horizon overlays measure and draw no text instead of panicking.

crates/horizon-client-input/Cargo.toml

@@ -9,11 +9,13 @@ description = "The client's input layer: key bindings and their names, mouse, co
 [dependencies]
 horizon-client-core = { path = "../horizon-client-core" }
 winit = "0.30.13"
-# The window icon.
-horizon-theme = { path = "../horizon-theme" }
 png = "0.18"
 arboard = { version = "3.6.1", default-features = false, features = ["wayland-data-control"] }
 
+[dev-dependencies]
+# The window icon test decodes Horizon's icon.
+horizon-theme = { path = "../horizon-theme" }
+
 [features]
 controllers = []
 

crates/horizon-client-input/src/window.rs

@@ -638,10 +638,30 @@ pub fn fullscreen_request(
     }
 }
 
-/// Horizon's icon for the window's title bar and the task bar (X11 and Windows; Wayland takes
-/// it from the `horizon.desktop` entry, macOS from the app bundle). `None` if it can't be read.
+/// The PNG the windows show as their icon, given once at startup by the layer that brands the
+/// game (the engine has none of its own).
+static ICON_PNG: std::sync::OnceLock<&'static [u8]> = std::sync::OnceLock::new();
+
+/// Give the windows their icon, a PNG: call it before the first window opens. A second call
+/// keeps the first icon.
+pub fn set_icon_png(png: &'static [u8]) {
+    let _ = ICON_PNG.set(png);
+}
+
+/// The icon given to [`set_icon_png`], if any.
+pub fn icon_png() -> Option<&'static [u8]> {
+    ICON_PNG.get().copied()
+}
+
+/// The icon for the window's title bar and the task bar (X11 and Windows; Wayland takes it from
+/// the `.desktop` entry, macOS from the app bundle). `None` with no icon given, or one that
+/// can't be read.
 pub fn icon() -> Option<winit::window::Icon> {
-    let mut decoder = png::Decoder::new(std::io::Cursor::new(horizon_theme::ICON_PNG));
+    decode_icon(icon_png()?)
+}
+
+fn decode_icon(png: &[u8]) -> Option<winit::window::Icon> {
+    let mut decoder = png::Decoder::new(std::io::Cursor::new(png));
     decoder.ignore_checksums(true);
     decoder.set_transformations(png::Transformations::EXPAND | png::Transformations::STRIP_16);
     let mut reader = decoder.read_info().ok()?;
@@ -654,14 +674,15 @@ pub fn icon() -> Option<winit::window::Icon> {
     winit::window::Icon::from_rgba(bytes, info.width, info.height).ok()
 }
 
-/// Apply Horizon's icon to every window. Windows has a separate taskbar icon slot from the small
-/// window icon; requiring the decoded icon there prevents a generic taskbar icon from appearing.
-pub fn with_horizon_icon(
-    attributes: winit::window::WindowAttributes,
-) -> winit::window::WindowAttributes {
+/// Apply the icon given to [`set_icon_png`] to a window. Windows has a separate taskbar icon slot
+/// from the small window icon; requiring a given icon to decode there prevents a generic taskbar
+/// icon from appearing.
+pub fn with_icon(attributes: winit::window::WindowAttributes) -> winit::window::WindowAttributes {
+    #[cfg(not(target_os = "windows"))]
     let icon = icon();
     #[cfg(target_os = "windows")]
-    let icon = Some(icon.expect("Horizon's icon must be available on Windows"));
+    let icon =
+        icon_png().map(|png| decode_icon(png).expect("the window icon must decode on Windows"));
 
     let attributes = attributes.with_window_icon(icon.clone());
     #[cfg(target_os = "windows")]
@@ -706,7 +727,8 @@ mod tests {
     }
     #[test]
     fn the_window_icon_decodes() {
-        assert!(icon().is_some());
+        assert!(decode_icon(horizon_theme::ICON_PNG).is_some());
+        assert!(decode_icon(b"not a png").is_none());
     }
 
     #[test]

crates/horizon-client-lib/Cargo.toml

@@ -72,7 +72,6 @@ flate2 = { version = "1.1.10", default-features = false, features = ["zlib-rs",
 mio = { version = "1.2.4", features = ["os-poll", "net"] }
 # Shared chunk frames are found by one keyed 128-bit hash of their body (lan/conn.rs SharedFrames).
 xxhash-rust = { version = "0.8.19", features = ["xxh3"] }
-horizon-theme = { path = "../horizon-theme" }
 # Opt-in data collection: the game keeps, the launcher sends (docs/telemetry.md).
 horizon-telemetry = { path = "../horizon-telemetry", default-features = false }
 horizon-bench = { path = "../horizon-bench" }
@@ -132,6 +131,8 @@ windows-segment-heap = []
 workspace = true
 
 [dev-dependencies]
+# ui_theme's unit tests draw text in the design system's fonts.
+horizon-theme = { path = "../horizon-theme" }
 horizon-client-render = { path = "../horizon-client-render", features = ["test-support"] }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 # Every WGSL shader translated as wgpu's DirectX 12 backend does (gfx.rs tests).

crates/horizon-client-render/Cargo.toml

@@ -30,7 +30,6 @@ horizon-render-pipeline = { path = "../horizon-render-pipeline" }
 horizon-shader-api = { path = "../horizon-shader-api" }
 horizon-shaders = { path = "../horizon-shaders" }
 horizon-system = { path = "../horizon-system" }
-horizon-theme = { path = "../horizon-theme" }
 horizon-threads = { path = "../horizon-threads" }
 horizon-world = { path = "../horizon-world" }
 ab_glyph = "0.2.32"
@@ -82,5 +81,7 @@ test-support = []
 workspace = true
 
 [dev-dependencies]
+# Tests: a TrueType font to load, and the design system the menus' motion curves match.
+horizon-theme = { path = "../horizon-theme" }
 horizon-items = { path = "../horizon-items", features = ["test-support"] }
 naga = { version = "30.0.1", features = ["wgsl-in", "hlsl-out", "glsl-out", "msl-out", "spv-out"] }

crates/horizon-client-render/src/gfx/hdr.rs

@@ -1001,12 +1001,14 @@ impl Hdr {
     }
 }
 
-/// Horizon's icon (horizon-theme) as a 1-bit mask: its white strokes, one colour with hard
-/// edges, are the logo; everything else is not.
+/// The windows' icon (`window::set_icon_png`: Horizon's in the official game) as a 1-bit mask:
+/// its white strokes, one colour with hard edges, are the logo; everything else is not. No icon
+/// given: an empty mask.
 fn logo_mask(device: &wgpu::Device, queue: &wgpu::Queue) -> wgpu::TextureView {
     use wgpu::util::DeviceExt;
-    let (w, h, rgba) =
-        crate::hud::decode_bytes(horizon_theme::ICON_PNG).unwrap_or((1, 1, vec![0; 4]));
+    let (w, h, rgba) = horizon_client_input::window::icon_png()
+        .and_then(|png| crate::hud::decode_bytes(png).ok())
+        .unwrap_or((1, 1, vec![0; 4]));
     let mask: Vec<u8> = rgba
         .as_chunks::<4>()
         .0

crates/horizon-client-render/src/graphics_style.rs

@@ -2,16 +2,21 @@
 //! colours and the controls it draws with. The screen (`graphics_ui`) only
 //! lays out rows and handles input; a menu theme replaces this module.
 //!
-//! It takes the design system's Blocks palette (`horizon_theme::BLOCKS_DARK`,
-//! `docs/design-system.md`) in a lighter form: square panels of dark glass
-//! with a thin edge, so the world shows through, flat controls, and the violet
-//! face on the one main button, in vanilla's font.
+//! Its colours come from `menu_style`, given at startup (in the official game the design
+//! system's Blocks palette, `docs/design-system.md`), in a lighter form: square panels of
+//! dark glass with a thin edge, so the world shows through, flat controls, and the face on
+//! the one main button, in vanilla's font.
+use crate::menu_style::{self, SettingsColours};
 use crate::{
     hud::{HudAtlas, HudBatch},
     text::Text,
     ui,
 };
-use horizon_theme::BLOCKS_DARK as B;
+
+/// The settings pages' colours (`menu_style`, given at startup).
+fn b() -> &'static SettingsColours {
+    &menu_style::get().settings
+}
 
 /// What a setting costs in frame time, shown with its description.
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
@@ -36,54 +41,91 @@ impl Cost {
     /// `0xRRGGBB`: the palette's success, warn and danger.
     pub fn rgb(self) -> u32 {
         match self {
-            Cost::None => B.ink_soft,
-            Cost::Low | Cost::Saves => B.success,
-            Cost::Medium => B.warn,
-            Cost::High => B.danger,
+            Cost::None => b().ink_soft,
+            Cost::Low | Cost::Saves => b().success,
+            Cost::Medium => b().warn,
+            Cost::High => b().danger,
         }
     }
 }
 
-/// `0xRRGGBB` and an alpha in the HUD's colour encoding.
-const fn hex(c: u32, a: u8) -> u32 {
-    (a as u32) << 24 | (c & 0xff) << 16 | (c >> 8 & 0xff) << 8 | (c >> 16 & 0xff)
-}
+use menu_style::hud_colour as hex;
 /// The plate and the strip: the page's dark, see-through, so the world shows behind them.
-const GLASS: u32 = hex(B.page, 118);
+fn glass() -> u32 {
+    hex(b().page, 118)
+}
 /// Their 1 px edge.
-const EDGE: u32 = hex(B.ink, 26);
+pub fn edge() -> u32 {
+    hex(b().ink, 26)
+}
 /// A group's panel, a little lighter than the plate it sits on.
-const GROUP: u32 = hex(B.ink, 11);
+fn group_fill() -> u32 {
+    hex(b().ink, 11)
+}
 /// A hovered or focused row, lit on its group's panel.
-pub const HOVER: u32 = hex(B.ink, 18);
+pub fn hover() -> u32 {
+    hex(b().ink, 18)
+}
 /// The open page in the page list.
-pub const OPEN: u32 = hex(B.ink, 26);
+pub fn open() -> u32 {
+    hex(b().ink, 26)
+}
 /// The rule under the plate's heading, and between two rows of a group.
-pub const HEAD_RULE: u32 = hex(B.ink, 31);
-pub const ROW_RULE: u32 = hex(B.ink, 15);
+pub fn head_rule() -> u32 {
+    hex(b().ink, 31)
+}
+pub fn row_rule() -> u32 {
+    hex(b().ink, 15)
+}
 /// Fields, boxes and the value stepper: sunk, see-through.
-const WELL: u32 = hex(B.outline, 102);
+fn well_fill() -> u32 {
+    hex(b().outline, 102)
+}
 /// A button, a slider's track, the scroller's thumb.
-const BUTTON: u32 = hex(B.ink, 20);
-const BUTTON_HOVER: u32 = hex(B.ink, 41);
-const TRACK: u32 = hex(B.ink, 64);
-const HANDLE: u32 = hex(B.ink, 255);
+fn button_fill() -> u32 {
+    hex(b().ink, 20)
+}
+fn button_hover() -> u32 {
+    hex(b().ink, 41)
+}
+fn track_fill() -> u32 {
+    hex(b().ink, 64)
+}
+fn handle_fill() -> u32 {
+    hex(b().ink, 255)
+}
 /// The one main button.
-const FACE: u32 = hex(B.face, 255);
-const FACE_HOVER: u32 = hex(0x6a50e6, 255);
+pub fn face() -> u32 {
+    hex(b().face, 255)
+}
+fn face_hover() -> u32 {
+    hex(b().face_hover, 255)
+}
 /// A tick box's edge when off.
-const BOX_EDGE: u32 = hex(B.ink_soft, 89);
-const OUTLINE: u32 = hex(B.outline, 255);
-pub const ACCENT: u32 = hex(B.accent, 255);
+fn box_edge() -> u32 {
+    hex(b().ink_soft, 89)
+}
+fn outline() -> u32 {
+    hex(b().outline, 255)
+}
+pub fn accent() -> u32 {
+    hex(b().accent, 255)
+}
 /// Vanilla's white text, and its grey for what can't be used now.
 pub const WHITE: u32 = u32::MAX;
-pub const MUTED: u32 = hex(B.muted, 255);
+pub fn muted() -> u32 {
+    hex(b().muted, 255)
+}
 /// A page that isn't open, a value at rest.
-pub const SOFT: u32 = hex(B.ink_soft, 255);
+pub fn soft() -> u32 {
+    hex(b().ink_soft, 255)
+}
 /// Vanilla's grey for a tooltip's lines under its first (`ChatFormatting.GRAY`).
 pub const GREY: u32 = hex(0xaaaaaa, 255);
 /// A light veil over the backdrop, under the panels.
-pub const VEIL: u32 = hex(B.page, 77);
+pub fn veil() -> u32 {
+    hex(b().page, 77)
+}
 
 /// Sizes in GUI pixels.
 /// Shorter screens than this (a 720p window at scale 3) keep a narrower margin on top.
@@ -120,21 +162,21 @@ pub fn ring(batch: &mut HudBatch, atlas: &HudAtlas, [x, y, w, h]: [f32; 4], colo
 }
 /// The screen's plate, and the strip under it: dark glass with a thin edge.
 pub fn panel(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GLASS);
-    ring(batch, atlas, rect, EDGE);
+    fill(batch, atlas, rect, glass());
+    ring(batch, atlas, rect, edge());
 }
 /// A group's panel on the plate, its rows on it.
 pub fn group(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, GROUP);
+    fill(batch, atlas, rect, group_fill());
 }
 /// A sunk well: the search field, the value stepper.
 pub fn well(batch: &mut HudBatch, atlas: &HudAtlas, rect: [f32; 4]) {
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
 }
 /// The scroller: a faint track and its thumb.
 pub fn scroller(batch: &mut HudBatch, atlas: &HudAtlas, track: [f32; 4], thumb: [f32; 4]) {
-    fill(batch, atlas, track, ROW_RULE);
-    fill(batch, atlas, thumb, TRACK);
+    fill(batch, atlas, track, row_rule());
+    fill(batch, atlas, thumb, track_fill());
 }
 /// `text` cut to `width` with an ellipsis, as a long name gives way to its control: the HUD
 /// kit's `fit::ellipsize`.
@@ -142,11 +184,11 @@ pub use crate::hud_kit::fit::ellipsize as fit;
 /// A 12 px tick box ending at `right`, centred in the row at `y`: its edge in the accent when on.
 pub fn checkbox(batch: &mut HudBatch, atlas: &HudAtlas, right: f32, y: f32, on: bool, live: bool) {
     let rect = [right - 12.0, y + 4.0, 12.0, 12.0];
-    fill(batch, atlas, rect, WELL);
+    fill(batch, atlas, rect, well_fill());
     let edge = match (on, live) {
-        (true, true) => ACCENT,
-        (true, false) => MUTED,
-        (false, _) => BOX_EDGE,
+        (true, true) => accent(),
+        (true, false) => muted(),
+        (false, _) => box_edge(),
     };
     ring(batch, atlas, rect, edge);
     if on {
@@ -169,7 +211,7 @@ fn tick(batch: &mut HudBatch, atlas: &HudAtlas, x: f32, y: f32, color: u32) {
         for (i, c) in row.chars().enumerate() {
             if c == '#' {
                 let (px, py) = (x + i as f32, y + j as f32);
-                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], OUTLINE);
+                fill(batch, atlas, [px + 1.0, py + 1.0, 1.0, 1.0], outline());
                 fill(batch, atlas, [px, py, 1.0, 1.0], color);
             }
         }
@@ -198,17 +240,17 @@ pub fn button_with_room(
 ) {
     let [x, y, w, h] = rect;
     let face = match (live, primary, hover) {
-        (false, _, _) => WELL,
-        (true, true, false) => FACE,
-        (true, true, true) => FACE_HOVER,
-        (true, false, false) => BUTTON,
-        (true, false, true) => BUTTON_HOVER,
+        (false, _, _) => well_fill(),
+        (true, true, false) => face(),
+        (true, true, true) => face_hover(),
+        (true, false, false) => button_fill(),
+        (true, false, true) => button_hover(),
     };
     fill(batch, atlas, rect, face);
     if hover && live {
         ring(batch, atlas, rect, WHITE);
     }
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
     let ty = y + ((h - 8.0) / 2.0).floor();
     let left = x + 2.0 + room;
     scrolling_label(
@@ -252,7 +294,7 @@ pub fn slider(
     (hover, live): (bool, bool),
 ) {
     let [x, y, w, h] = rect;
-    let color = if live { WHITE } else { MUTED };
+    let color = if live { WHITE } else { muted() };
     scrolling_label(
         batch,
         atlas,
@@ -263,17 +305,22 @@ pub fn slider(
     );
     let line = y + h - 3.0;
     let at = x + (position.clamp(0.0, 1.0) * (w - 4.0)).round();
-    fill(batch, atlas, [x, line, w, 2.0], TRACK);
+    fill(batch, atlas, [x, line, w, 2.0], track_fill());
     fill(
         batch,
         atlas,
         [x, line, at - x, 2.0],
-        if live { ACCENT } else { MUTED },
+        if live { accent() } else { muted() },
     );
     let handle = [at, line - 3.0, 4.0, 8.0];
-    fill(batch, atlas, handle, if live { HANDLE } else { MUTED });
+    fill(
+        batch,
+        atlas,
+        handle,
+        if live { handle_fill() } else { muted() },
+    );
     if hover && live {
-        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], ACCENT);
+        ring(batch, atlas, [at - 1.0, line - 4.0, 6.0, 10.0], accent());
     }
 }
 /// A value that a press steps through: in a well, between the arrows that say so.
@@ -290,13 +337,13 @@ pub fn cycler(
         ring(batch, atlas, rect, WHITE);
     }
     let ty = y + ((h - 8.0) / 2.0).floor();
-    let arrows = if hover && live { WHITE } else { MUTED };
+    let arrows = if hover && live { WHITE } else { muted() };
     batch.text_styled(atlas, &Text::literal("<"), x + 3.0, ty, arrows, true);
     batch.text_styled(atlas, &Text::literal(">"), x + w - 8.0, ty, arrows, true);
     let color = match (live, hover) {
-        (false, _) => MUTED,
+        (false, _) => muted(),
         (true, true) => WHITE,
-        (true, false) => SOFT,
+        (true, false) => soft(),
     };
     scrolling_label(batch, atlas, value, [x + 9.0, ty, w - 18.0], (y, h), color);
 }

crates/horizon-client-render/src/hud_kit/motion.rs

@@ -3,8 +3,9 @@
 //! where a tween is at the frame's [`Clock`]; nothing here holds state or runs on its own, and
 //! no motion ever decides what input does.
 //!
-//! The curves are the design system's (`horizon_theme::QUICK`, `MOVE`): a [`Tween`] takes one
-//! of them, at the theme's duration or a shorter one of its own.
+//! A [`Tween`] takes a duration and a CSS `cubic-bezier` curve: Horizon's overlays use the design
+//! system's (`horizon_theme::QUICK`, `MOVE`), at the theme's duration or a shorter one of their
+//! own.
 //!
 //! The game builds the clock once a frame (`Clock::new(now, still)`). A still clock (the game is
 //! paused, frame-stepped by `HORIZON_STILL` or a screenshot sequence, or a repro recording or
@@ -16,7 +17,7 @@
 //! use std::time::{Duration, Instant};
 //!
 //! let opened = Instant::now();
-//! let open = Tween::new(Duration::from_millis(90), horizon_theme::QUICK);
+//! let open = Tween::new(Duration::from_millis(90), [0.4, 0.0, 0.2, 1.0]);
 //! // Half way through: partly faded in, partly grown from 94%.
 //! let clock = Clock::new(opened + Duration::from_millis(45), false);
 //! let alpha = motion::fade(open, clock, opened);
@@ -26,7 +27,6 @@
 //! let still = Clock::new(opened, true);
 //! assert_eq!(motion::fade(open, still, opened), 1.0);
 //! ```
-use horizon_theme::Motion;
 use std::time::{Duration, Instant};
 
 /// The time a frame shows, built once a frame by the game.
@@ -50,28 +50,20 @@ impl Clock {
     }
 }
 
-/// A duration and one of the design system's easing curves.
+/// A duration and an easing curve.
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Tween {
     /// How long it runs.
     pub duration: Duration,
-    /// The CSS `cubic-bezier` control points of its curve (a `horizon_theme::Motion`'s).
+    /// The CSS `cubic-bezier` control points of its curve.
     pub curve: [f32; 4],
 }
 
 impl Tween {
-    /// `motion`'s curve over `duration`: the dial's motions are shorter than the launcher's, on
-    /// the same curves.
-    pub const fn new(duration: Duration, motion: Motion) -> Self {
-        Self {
-            duration,
-            curve: motion.curve,
-        }
-    }
-
-    /// A theme motion as it is: its own duration and curve.
-    pub const fn of(motion: Motion) -> Self {
-        Self::new(motion.duration(), motion)
+    /// `curve` over `duration`: the dial's motions are shorter than the launcher's, on the same
+    /// curves.
+    pub const fn new(duration: Duration, curve: [f32; 4]) -> Self {
+        Self { duration, curve }
     }
 
     /// The linear progress, 0 to 1, `since` a start at this clock; 1 on a still clock.
@@ -84,7 +76,7 @@ impl Tween {
 
     /// The eased progress, 0 to 1, on the tween's curve.
     pub fn progress(self, clock: Clock, since: Instant) -> f32 {
-        horizon_theme::bezier(self.curve, self.linear(clock, since))
+        bezier(self.curve, self.linear(clock, since))
     }
 
     /// Whether it has finished (always, on a still clock).
@@ -98,6 +90,29 @@ impl Tween {
     }
 }
 
+/// A CSS `cubic-bezier(x1, y1, x2, y2)` at `t` in 0..1: solves x for the curve parameter,
+/// returns y.
+pub fn bezier([x1, y1, x2, y2]: [f32; 4], t: f32) -> f32 {
+    let t = t.clamp(0.0, 1.0);
+    if t == 0.0 || t == 1.0 {
+        return t;
+    }
+    let at = |a: f32, b: f32, s: f32| {
+        let u = 1.0 - s;
+        3.0 * u * u * s * a + 3.0 * u * s * s * b + s * s * s
+    };
+    let (mut lo, mut hi) = (0f32, 1f32);
+    for _ in 0..24 {
+        let mid = (lo + hi) / 2.0;
+        if at(x1, x2, mid) < t {
+            lo = mid;
+        } else {
+            hi = mid;
+        }
+    }
+    at(y1, y2, (lo + hi) / 2.0)
+}
+
 /// An alpha from 0 to 1 as something fades in.
 pub fn fade(tween: Tween, clock: Clock, since: Instant) -> f32 {
     tween.progress(clock, since)
@@ -145,7 +160,7 @@ mod tests {
     #[test]
     fn a_tween_runs_from_its_start_to_its_end_and_holds() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
         assert_eq!(tween.progress(at(t0, 0), t0), 0.0);
         assert_eq!(tween.progress(at(t0, 80), t0), 1.0);
         assert_eq!(tween.progress(at(t0, 500), t0), 1.0);
@@ -160,8 +175,7 @@ mod tests {
     fn a_still_clock_shows_every_motion_settled() {
         let t0 = Instant::now();
         let still = Clock::new(t0, true);
-        let tween = Tween::of(horizon_theme::QUICK);
-        assert_eq!(tween.duration, horizon_theme::QUICK.duration());
+        let tween = Tween::new(horizon_theme::QUICK.duration(), horizon_theme::QUICK.curve);
         assert_eq!(fade(tween, still, t0), 1.0);
         assert_eq!(fade_out(tween, still, t0), 0.0);
         assert_eq!(scale_in(tween, still, t0, 0.94), 1.0);
@@ -173,7 +187,7 @@ mod tests {
     #[test]
     fn the_helpers_start_where_they_say() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(100), horizon_theme::QUICK);
+        let tween = Tween::new(MS(100), horizon_theme::QUICK.curve);
         let c = at(t0, 0);
         assert_eq!(fade(tween, c, t0), 0.0);
         assert_eq!(fade_out(tween, c, t0), 1.0);
@@ -184,10 +198,25 @@ mod tests {
         assert!((flash(tween, at(t0, 25), t0) - 0.75).abs() < 1e-6);
     }
 
+    #[test]
+    fn the_curve_is_the_design_systems() {
+        for motion in horizon_theme::MOTION {
+            for i in 0..=20 {
+                let t = i as f32 / 20.0;
+                assert_eq!(
+                    bezier(motion.curve, t),
+                    motion.ease(t),
+                    "{} at {t}",
+                    motion.name
+                );
+            }
+        }
+    }
+
     #[test]
     fn a_turn_takes_the_short_way_round() {
         let t0 = Instant::now();
-        let tween = Tween::new(MS(80), horizon_theme::MOVE);
+        let tween = Tween::new(MS(80), horizon_theme::MOVE.curve);
         // From up-left (7/8 of a turn) to up-right: through up, not round the bottom.
         let from = 7.0 * FRAC_PI_4;
         let half = turn(tween, at(t0, 1), t0, from, FRAC_PI_4);

crates/horizon-client-render/src/hud_kit/tabs.rs

@@ -38,6 +38,12 @@
 //! ```
 use crate::hud::{HudAtlas, HudBatch};
 use crate::hud_kit::{colour, fit};
+use crate::menu_style::{self, OverlayColours};
+
+/// The overlays' colours (`menu_style`, given at startup).
+fn overlay() -> &'static OverlayColours {
+    &menu_style::get().overlay
+}
 
 /// A pip under the strip: its size and the step from one to the next, in GUI px.
 pub const PIP: [f32; 2] = [3.0, 2.0];
@@ -45,8 +51,12 @@ pub const PIP_STEP: f32 = 5.0;
 /// How far, in GUI px, the arrows sit from the name.
 pub const ARROW_GAP: f32 = 4.0;
 /// An arrow with a page that way, and one at an end, with none.
-pub const ARROW: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
-pub const ARROW_OFF: u32 = colour(horizon_theme::BACKDROP_MUTED, 77);
+pub fn arrow_colour() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
+pub fn arrow_off_colour() -> u32 {
+    colour(overlay().backdrop_muted, 77)
+}
 /// The pips (the selected one is white).
 pub const PIP_OFF: u32 = colour(0xFFFFFF, 89);
 pub const PIP_ON: u32 = colour(0xFFFFFF, 255);
@@ -65,9 +75,15 @@ pub const EDGE_FADE: f32 = 12.0;
 pub const FADE: [f32; 5] = [1.0, 0.7, 0.35, 0.15, 0.1];
 /// The selected tab's fill and text, and the others'.
 pub const SELECTED_FILL: u32 = colour(0xFFFFFF, 242);
-pub const SELECTED_TEXT: u32 = colour(horizon_theme::DARK.page, 255);
-pub const TAB_FILL: u32 = colour(horizon_theme::DARK.page, 191);
-pub const TAB_TEXT: u32 = colour(horizon_theme::BACKDROP_MUTED, 255);
+pub fn selected_text() -> u32 {
+    colour(overlay().page, 255)
+}
+pub fn tab_fill() -> u32 {
+    colour(overlay().page, 191)
+}
+pub fn tab_text() -> u32 {
+    colour(overlay().backdrop_muted, 255)
+}
 /// The line of text's height in GUI px (vanilla's font, without its shadow).
 const LINE: f32 = 8.0;
 
@@ -144,7 +160,11 @@ pub fn draw(batch: &mut HudBatch, atlas: &HudAtlas, strip: &Strip) {
             arrow,
             ax,
             ay,
-            if on { ARROW } else { ARROW_OFF },
+            if on {
+                arrow_colour()
+            } else {
+                arrow_off_colour()
+            },
             true,
         );
     }
@@ -282,9 +302,9 @@ pub fn draw_tabs(batch: &mut HudBatch, atlas: &HudAtlas, strip: &TabStrip, alpha
     for tab in &row.tabs {
         let [tx, ty, tw, th] = tab.area;
         let (fill, text) = if tab.selected {
-            (SELECTED_FILL, SELECTED_TEXT)
+            (SELECTED_FILL, selected_text())
         } else {
-            (TAB_FILL, TAB_TEXT)
+            (tab_fill(), tab_text())
         };
         let tab_start = batch.vertices.len();
         // Cut where the edges' fades start, so each fade runs over its own piece.
@@ -380,15 +400,16 @@ mod tests {
             let [ax, _] = strip.arrows[i];
             (batch.vertices.iter())
                 .filter(|v| {
-                    (v.pos[0] - ax).abs() < 4.0 && v.color & 0x00FF_FFFF == ARROW & 0x00FF_FFFF
+                    (v.pos[0] - ax).abs() < 4.0
+                        && v.color & 0x00FF_FFFF == arrow_colour() & 0x00FF_FFFF
                 })
                 .map(|v| v.color >> 24)
                 .max()
                 .unwrap_or(0)
         };
         let first = collapsed(&atlas, &pages, 0, AREA);
-        assert_eq!(alpha(&first, 0), ARROW_OFF >> 24);
-        assert_eq!(alpha(&first, 1), ARROW >> 24);
+        assert_eq!(alpha(&first, 0), arrow_off_colour() >> 24);
+        assert_eq!(alpha(&first, 1), arrow_colour() >> 24);
     }
 
     #[test]

crates/horizon-client-render/src/lib.rs

@@ -75,6 +75,7 @@ pub mod light;
 pub mod lod;
 pub mod logging;
 pub mod menu_blur;
+pub mod menu_style;
 pub mod mesher;
 pub mod minimap;
 pub mod mipmap;

crates/horizon-client-render/src/menu_style.rs

@@ -0,0 +1,145 @@
+//! The look of the screens vanilla doesn't have that the engine still draws: the settings pages
+//! (`graphics_style`), the HUD kit's tab strip, and the overlays drawn with `ui_theme` (the
+//! on-screen keyboard, the boot screen, the missing-resources window). Vanilla's screens never
+//! read it.
+//!
+//! The layer above gives it once at startup ([`install`]), before the first frame; the
+//! official game gives Horizon's design system (`docs/design-system.md`). With none given, the
+//! screens draw in [`NEUTRAL`]: vanilla's greys and chat colours, and no text where they would
+//! use their own fonts. A read is one atomic load, and only those screens make it.
+use std::sync::OnceLock;
+
+/// Colours as `0xRRGGBB`, sizes in dp (the launcher's logical pixels).
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct MenuStyle {
+    pub settings: SettingsColours,
+    pub overlay: OverlayColours,
+    pub sizes: Sizes,
+    /// The overlays' TrueType faces; none: they draw no text.
+    pub fonts: Option<Fonts>,
+}
+
+/// The settings pages: square panels of dark glass over the world, flat controls, one face.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct SettingsColours {
+    /// The plate behind everything, drawn see-through.
+    pub page: u32,
+    /// Text, and the light the panels, rules, hovers and controls are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// Labels, descriptions, what can't be used.
+    pub muted: u32,
+    /// Wells and the dark edge of small marks.
+    pub outline: u32,
+    /// Focus, a checked box, a slider's fill.
+    pub accent: u32,
+    /// The one main button, and while hovered.
+    pub face: u32,
+    pub face_hover: u32,
+    pub success: u32,
+    pub warn: u32,
+    pub danger: u32,
+}
+
+/// Overlays drawn over the game (the HUD kit's tab strip, `ui_theme`'s overlays).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct OverlayColours {
+    /// The dark page under text and tabs.
+    pub page: u32,
+    /// Muted text over a veiled backdrop.
+    pub backdrop_muted: u32,
+    /// Text and the light hover and pressed plates are drawn in.
+    pub ink: u32,
+    /// Secondary text and values.
+    pub ink_soft: u32,
+    /// One-pixel rules between rows.
+    pub rule: u32,
+    /// The main action, and its text.
+    pub accent: u32,
+    pub on_accent: u32,
+}
+
+/// `ui_theme`'s type scale and shapes, in dp.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Sizes {
+    pub caption: f32,
+    pub label: f32,
+    pub ui: f32,
+    pub body: f32,
+    pub title: f32,
+    /// The boot screen's wordmark at its smallest, and its console lines.
+    pub display: f32,
+    pub micro: f32,
+    /// Fields; plates (hover rows, selection); a large control's height.
+    pub radius: f32,
+    pub radius_plate: f32,
+    pub control_large: f32,
+}
+
+/// TrueType faces (`ui_theme::Face`).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub struct Fonts {
+    pub regular: &'static [u8],
+    pub medium: &'static [u8],
+    pub semibold: &'static [u8],
+    pub mono: &'static [u8],
+}
+
+/// The look with nothing given: vanilla's greys and chat colours.
+pub const NEUTRAL: MenuStyle = MenuStyle {
+    settings: SettingsColours {
+        page: 0x101010,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        muted: 0xa0a0a0,
+        outline: 0x000000,
+        accent: 0xffffff,
+        face: 0x555555,
+        face_hover: 0x6f6f6f,
+        success: 0x55ff55,
+        warn: 0xffff55,
+        danger: 0xff5555,
+    },
+    overlay: OverlayColours {
+        page: 0x101010,
+        backdrop_muted: 0xa0a0a0,
+        ink: 0xffffff,
+        ink_soft: 0xe0e0e0,
+        rule: 0x303030,
+        accent: 0xffffff,
+        on_accent: 0x000000,
+    },
+    sizes: Sizes {
+        caption: 12.0,
+        label: 13.0,
+        ui: 14.0,
+        body: 15.0,
+        title: 28.0,
+        display: 44.0,
+        micro: 11.0,
+        radius: 0.0,
+        radius_plate: 0.0,
+        control_large: 40.0,
+    },
+    fonts: None,
+};
+
+static STYLE: OnceLock<MenuStyle> = OnceLock::new();
+
+/// Give the menus their look: call it once at startup. A second call keeps the first look and
+/// returns false.
+pub fn install(style: MenuStyle) -> bool {
+    STYLE.set(style).is_ok()
+}
+
+/// The look given to [`install`], or [`NEUTRAL`].
+#[inline]
+pub fn get() -> &'static MenuStyle {
+    STYLE.get().unwrap_or(&NEUTRAL)
+}
+
+/// `0xRRGGBB` and an alpha in the HUD's colour encoding (`0xAABBGGRR`).
+pub const fn hud_colour(rgb: u32, alpha: u8) -> u32 {
+    (alpha as u32) << 24 | (rgb & 0xff) << 16 | (rgb >> 8 & 0xff) << 8 | (rgb >> 16 & 0xff)
+}

crates/horizon-client-render/src/settings_shell.rs

@@ -237,17 +237,17 @@ impl<P: Copy, S: Copy> Lines<P, S> {
 pub(crate) fn backdrop(batch: &mut HudBatch, atlas: &HudAtlas, in_world: bool) {
     let (w, h) = (batch.width, batch.height);
     ui::menu_background(batch, atlas, 0.0, 0.0, w, h, in_world);
-    style::fill(batch, atlas, [0.0, 0.0, w, h], style::VEIL);
+    style::fill(batch, atlas, [0.0, 0.0, w, h], style::veil());
 }
 
 /// The mark and the screen's name over the search field.
 pub(crate) fn mark(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, title: &str) {
     let (x, y) = (cols.side_x, cols.side_y);
-    style::fill(batch, atlas, [x, y + 2.0, 6.0, 6.0], style::ACCENT);
+    style::fill(batch, atlas, [x, y + 2.0, 6.0, 6.0], style::accent());
     let horizon = Text::literal("Horizon");
     batch.text_styled(atlas, &horizon, x + 10.0, y, style::WHITE, true);
     let title = Text::literal(title);
-    batch.text_styled(atlas, &title, x, y + 10.0, style::MUTED, true);
+    batch.text_styled(atlas, &title, x, y + 10.0, style::muted(), true);
 }
 
 /// A page in the page list: the open page on a plate with the accent's bar beside it, the
@@ -273,13 +273,13 @@ pub(crate) fn page_tab(
         crate::widgets::target_as(rect, crate::widgets::Kind::Tab(open));
     }
     if open {
-        style::fill(batch, atlas, rect, style::OPEN);
-        style::fill(batch, atlas, [px, py, 2.0, ph], style::ACCENT);
+        style::fill(batch, atlas, rect, style::open());
+        style::fill(batch, atlas, [px, py, 2.0, ph], style::accent());
     }
     let color = match (open || hover, has) {
         (true, _) => style::WHITE,
-        (false, true) => style::SOFT,
-        (false, false) => style::MUTED,
+        (false, true) => style::soft(),
+        (false, false) => style::muted(),
     };
     let ty = py + ((ph - 8.0) / 2.0).floor();
     let name = Text::literal(style::fit(atlas, name, pw - 12.0));
@@ -312,12 +312,12 @@ pub(crate) fn search_field(
     search.draw(batch, atlas, None);
     if search.value.is_empty() && !focused {
         let hint = Text::literal(search.message.clone());
-        batch.text_styled(atlas, &hint, x + 5.0, search.y, style::MUTED, true);
+        batch.text_styled(atlas, &hint, x + 5.0, search.y, style::muted(), true);
     }
     if !search.value.is_empty() {
         let hover = ui::hovered(cursor, clear[0], clear[1], clear[2], clear[3]);
         crate::widgets::widget_cursor(hover, true);
-        let color = if hover { style::WHITE } else { style::MUTED };
+        let color = if hover { style::WHITE } else { style::muted() };
         let cy = y + ((h - 8.0) / 2.0).floor();
         ui::centered_text(
             batch,
@@ -344,7 +344,7 @@ pub(crate) fn plate(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, head
         batch,
         atlas,
         [px + 8.0, py + 24.0, pw - 16.0, 1.0],
-        style::HEAD_RULE,
+        style::head_rule(),
     );
 }
 
@@ -383,9 +383,9 @@ pub(crate) fn list<P: Copy, S: Copy>(
         }
         let Some(setting) = line.setting else {
             let (name, color, dy) = match line.group {
-                Some(("", _)) => (page_name(line.page), style::MUTED, 3.0),
-                Some((name, _)) => (lang::get(name), style::MUTED, 3.0),
-                None => (page_name(line.page), style::ACCENT, 4.0),
+                Some(("", _)) => (page_name(line.page), style::muted(), 3.0),
+                Some((name, _)) => (lang::get(name), style::muted(), 3.0),
+                None => (page_name(line.page), style::accent(), 4.0),
             };
             let name = Text::literal(name);
             batch.text_styled(atlas, &name, cols.list_x + 2.0, y + dy, color, true);
@@ -393,7 +393,7 @@ pub(crate) fn list<P: Copy, S: Copy>(
         };
         if !after_name {
             let rule = [cols.list_x + 8.0, y, cols.list_w - 16.0, 1.0];
-            style::fill(batch, atlas, rule, style::ROW_RULE);
+            style::fill(batch, atlas, rule, style::row_rule());
         }
         row(batch, setting, y);
     }
@@ -404,7 +404,7 @@ pub(crate) fn list<P: Copy, S: Copy>(
             &none,
             cols.list_x + 2.0,
             cols.top + 4.0,
-            style::MUTED,
+            style::muted(),
             true,
         );
     }
@@ -499,7 +499,7 @@ pub(crate) fn row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32
     let active = live && (hover || focused || held);
     if active {
         let lit = [rect[0] + 2.0, y + 1.0, rect[2] - 4.0, style::ROW - 2.0];
-        style::fill(batch, atlas, lit, style::HOVER);
+        style::fill(batch, atlas, lit, style::hover());
     }
     crate::widgets::widget_cursor(hover, live);
     // The control socket's widget tree, the narrator and a controller's focus.
@@ -523,8 +523,8 @@ pub(crate) fn row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32
     if live {
         crate::widgets::target_as(rect, kind);
     }
-    let color = if live { style::WHITE } else { style::MUTED };
-    let soft = if live { style::SOFT } else { style::MUTED };
+    let color = if live { style::WHITE } else { style::muted() };
+    let soft = if live { style::soft() } else { style::muted() };
     let ty = y + ((style::ROW - 8.0) / 2.0).floor();
     let lit = live && (hover || held);
     let left = rect[0] + style::INSET;
@@ -611,7 +611,7 @@ fn lit(batch: &mut HudBatch, atlas: &HudAtlas, [x, y, w, _]: [f32; 4]) {
         batch,
         atlas,
         [x + 2.0, y + 1.0, w - 4.0, style::ROW - 2.0],
-        style::HOVER,
+        style::hover(),
     );
 }
 
@@ -644,7 +644,7 @@ fn read_row(
     let room = rect[2] - 2.0 * style::INSET - name_w - 8.0;
     let value = style::fit(atlas, value, room);
     let vx = rect[0] + rect[2] - style::INSET - atlas.font.width(&value);
-    batch.text_styled(atlas, &Text::literal(value), vx, ty, style::SOFT, true);
+    batch.text_styled(atlas, &Text::literal(value), vx, ty, style::soft(), true);
     if focused {
         style::ring(
             batch,
@@ -749,7 +749,7 @@ fn pad_row(batch: &mut HudBatch, atlas: &HudAtlas, cols: &Columns, y: f32, view:
         batch.text_styled(atlas, &yellow(close), right.ceil(), ty, style::WHITE, true);
     }
     let left = rect[0] + style::INSET;
-    let color = if live { style::WHITE } else { style::MUTED };
+    let color = if live { style::WHITE } else { style::muted() };
     let shown = Text::literal(style::fit(atlas, name, chip[0] - 6.0 - left));
     batch.text_styled(atlas, &shown, left, ty, color, true);
     if focused {
@@ -799,7 +799,7 @@ fn side_lines(
         ];
         crate::widgets::record(line, rect, false);
         let shown = Text::literal(style::fit(atlas, line, rect[2]));
-        batch.text_styled(atlas, &shown, rect[0], rect[1], style::MUTED, true);
+        batch.text_styled(atlas, &shown, rect[0], rect[1], style::muted(), true);
     }
 }
 /// A line under the page list: its inset, and its height.
@@ -881,7 +881,7 @@ fn heading(batch: &mut HudBatch, atlas: &HudAtlas, text: &str, [x, y, w, _]: [f3
     let rect = [x + SIDE_INSET, y + HEADING_Y, w - 2.0 * SIDE_INSET, 8.0];
     crate::widgets::record(text, rect, false);
     let shown = Text::literal(style::fit(atlas, text, rect[2]));
-    batch.text_styled(atlas, &shown, rect[0], rect[1], style::MUTED, true);
+    batch.text_styled(atlas, &shown, rect[0], rect[1], style::muted(), true);
 }
 
 /// Vanilla's scroller, inside the panel's right edge, sized as `ui::Scroll` drags it.
@@ -1896,8 +1896,8 @@ impl<S: Screen> Shell<S> {
             // The row's page is open: lit as the list's open page is.
             if list.lit == Some(*shown) {
                 let row @ [x, y, _, h] = strip.area;
-                style::fill(batch, atlas, row, style::OPEN);
-                style::fill(batch, atlas, [x, y, 2.0, h], style::ACCENT);
+                style::fill(batch, atlas, row, style::open());
+                style::fill(batch, atlas, [x, y, 2.0, h], style::accent());
             }
             tabs::draw(batch, atlas, strip);
         }
@@ -2134,7 +2134,14 @@ impl<S: Screen> Shell<S> {
             crate::widgets::narratable(|| crate::widgets::Narratable::text(row.name.clone(), rect));
             let ty = y + ((style::ROW - 8.0) / 2.0).floor();
             let name = Text::literal(style::fit(atlas, &row.name, rect[2] - 2.0 * style::INSET));
-            batch.text_styled(atlas, &name, rect[0] + style::INSET, ty, style::MUTED, true);
+            batch.text_styled(
+                atlas,
+                &name,
+                rect[0] + style::INSET,
+                ty,
+                style::muted(),
+                true,
+            );
             return;
         }
         let over = |[x, y, w, h]: [f32; 4]| pointer.is_some_and(|at| ui::hovered(at, x, y, w, h));
@@ -2240,7 +2247,7 @@ impl<S: Screen> Shell<S> {
         // Labelled for the widget tree: what the strip says is what a test or an agent reads.
         crate::widgets::record(about, cols.dock, false);
         let color = if why.is_some() {
-            style::MUTED
+            style::muted()
         } else {
             style::GREY
         };

crates/horizon-client-render/src/studio_ui.rs

@@ -304,19 +304,19 @@ impl StudioUi {
 
                 // Card background & highlight
                 if is_selected {
-                    style::fill(batch, atlas, rect, style::OPEN);
+                    style::fill(batch, atlas, rect, style::open());
                 } else if is_hovered {
-                    style::fill(batch, atlas, rect, style::HOVER);
+                    style::fill(batch, atlas, rect, style::hover());
                 } else {
                     style::well(batch, atlas, rect);
                 }
 
                 let border_color = if is_selected {
-                    style::ACCENT
+                    style::accent()
                 } else if is_hovered {
                     style::WHITE
                 } else {
-                    style::ROW_RULE
+                    style::row_rule()
                 };
                 style::ring(batch, atlas, rect, border_color);
 

crates/horizon-client/src/client_lib.rs

@@ -17,8 +17,8 @@ pub use horizon_client_render::{
     containers, controller_ui, crash, custom_sky, datapack, dynamic_light, effects, environment,
     extras, fast_hash, fluid_render, fog, font, gfx, graphics, graphics_style, graphics_ui,
     hdr_calibration, hud, hud_kit, hud_layout, hud_overlays, inventory_effects, java_text,
-    jigsaw_block, json_folder, level_loading, light, lod, logging, menu_blur, mesher, minimap,
-    mipmap, mod_browser, mod_list, model_library, models, multiline_edit, native_emissive,
+    jigsaw_block, json_folder, level_loading, light, lod, logging, menu_blur, menu_style, mesher,
+    minimap, mipmap, mod_browser, mod_list, model_library, models, multiline_edit, native_emissive,
     options_file, options_fixes, options_ui, overlay, pack_browser, pack_formats, pack_hooks,
     pack_palette, pack_screen, packs, pad_cursor, pad_glyph, par, particles, poi_sections,
     polytone_colors, polytone_creative_tabs, polytone_post, post_chain, potent_sulfur, preedit,

crates/horizon-client/src/entry.rs

@@ -13,6 +13,7 @@ pub fn main_with(mods: crate::mod_api::Mods) {
         log::warn!("Trait mods already installed; ignoring the second list");
     }
     horizon_threads::configure_allocator();
+    crate::horizon_look::give();
     // OptiFine's and Polytone's pack formats (platform, docs/layers.md), before any pack loads.
     horizon_client::pack_formats::install();
     // horizon-extras (docs/forking.md): without the feature, no Horizon Settings or Mods page.

crates/horizon-client/src/game/loading_screen.rs

@@ -98,9 +98,8 @@ impl Loading {
             .map_or([1280, 720], |o| o.window_size)
             .map(f64::from);
         self.fullscreen = horizon_client::window::FullscreenState::new(fullscreen);
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        );
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"));
         // Wayland names the window by its app id, which the horizon.desktop entry matches.
         #[cfg(target_os = "linux")]
         let attributes = winit::platform::wayland::WindowAttributesExtWayland::with_name(
@@ -130,22 +129,25 @@ impl Loading {
         // redraw the same design when they start. GDI is unsafe:
         // horizon-threads holds it (this crate forbids unsafe code).
         #[cfg(target_os = "windows")]
-        let boot_paint_stop = hwnd(&window).map(|hwnd| {
-            let stop = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
-            let repaint_stop = stop.clone();
-            std::thread::spawn(move || {
-                while !repaint_stop.load(std::sync::atomic::Ordering::Relaxed) {
-                    horizon_threads::boot_paint::paint(
-                        hwnd,
-                        horizon_theme::fonts::GEIST_SEMIBOLD,
-                        horizon_theme::fonts::GEIST_MONO,
-                        &horizon_client::logging::recent_lines(),
-                    );
-                    std::thread::sleep(std::time::Duration::from_millis(300));
-                }
+        // In the fonts given to `menu_style`; with none, the window stays as it is.
+        let boot_paint_stop = hwnd(&window)
+            .zip(horizon_client::menu_style::get().fonts)
+            .map(|(hwnd, fonts)| {
+                let stop = std::sync::Arc::new(std::sync::atomic::AtomicBool::new(false));
+                let repaint_stop = stop.clone();
+                std::thread::spawn(move || {
+                    while !repaint_stop.load(std::sync::atomic::Ordering::Relaxed) {
+                        horizon_threads::boot_paint::paint(
+                            hwnd,
+                            fonts.semibold,
+                            fonts.mono,
+                            &horizon_client::logging::recent_lines(),
+                        );
+                        std::thread::sleep(std::time::Duration::from_millis(300));
+                    }
+                });
+                stop
             });
-            stop
-        });
         let offscreen = self.options.as_ref().is_some_and(|o| o.offscreen);
         let boot_step = startup::step("renderer.boot");
         match loading_renderer(

crates/horizon-client/src/game/no_resources.rs

@@ -93,10 +93,9 @@ impl ApplicationHandler for Missing {
         if self.window.is_some() {
             return;
         }
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        )
-        .with_inner_size(winit::dpi::LogicalSize::new(1040.0, 700.0));
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"))
+                .with_inner_size(winit::dpi::LogicalSize::new(1040.0, 700.0));
         let made = event_loop
             .create_window(attributes)
             .map_err(Into::into)

crates/horizon-client/src/game/split/windows.rs

@@ -516,10 +516,9 @@ impl<'a> Split<'a> {
                 continue;
             }
             // Opened without the focus: whoever types in the game's window keeps the keyboard.
-            let attributes =
-                horizon_client::window::with_horizon_icon(Window::default_attributes())
-                    .with_active(false)
-                    .with_visible(window_shown(true, self.offscreen));
+            let attributes = horizon_client::window::with_icon(Window::default_attributes())
+                .with_active(false)
+                .with_visible(window_shown(true, self.offscreen));
             // A monitor's window covers it, borderless. On macOS not the system's fullscreen, a
             // Space of its own that hides the other windows as it slides in.
             let placement = self.placement(*key).cloned();

crates/horizon-client/src/game/window_handler.rs

@@ -273,9 +273,8 @@ impl ApplicationHandler for Game<'_> {
         let fullscreen = self.settings.fullscreen || self.options.fullscreen;
         let size = self.options.window_size.map(f64::from);
         self.fullscreen = horizon_client::window::FullscreenState::new(fullscreen);
-        let attributes = horizon_client::window::with_horizon_icon(
-            Window::default_attributes().with_title("Horizon"),
-        );
+        let attributes =
+            horizon_client::window::with_icon(Window::default_attributes().with_title("Horizon"));
         // Wayland names the window by its app id, which the horizon.desktop entry matches.
         #[cfg(target_os = "linux")]
         let attributes = winit::platform::wayland::WindowAttributesExtWayland::with_name(

crates/horizon-client/src/horizon_look.rs

@@ -0,0 +1,56 @@
+//! Horizon's look, given to the engine's extension points at startup (docs/layers.md): the
+//! windows' icon and the colours, sizes and fonts of the menus vanilla doesn't have
+//! (`docs/design-system.md`).
+//! Its own module so it can leave the engine crate as a pure file move, for the official
+//! executable to call.
+use horizon_client::menu_style::{Fonts, MenuStyle, OverlayColours, SettingsColours, Sizes};
+use horizon_theme as theme;
+
+/// Give the engine Horizon's look; call it once, before the first window opens.
+pub(crate) fn give() {
+    horizon_client::window::set_icon_png(theme::ICON_PNG);
+    let (blocks, dark) = (theme::BLOCKS_DARK, theme::DARK);
+    horizon_client::menu_style::install(MenuStyle {
+        settings: SettingsColours {
+            page: blocks.page,
+            ink: blocks.ink,
+            ink_soft: blocks.ink_soft,
+            muted: blocks.muted,
+            outline: blocks.outline,
+            accent: blocks.accent,
+            face: blocks.face,
+            // The face's hover, lighter than `face`: the settings screen's own shade.
+            face_hover: 0x6a50e6,
+            success: blocks.success,
+            warn: blocks.warn,
+            danger: blocks.danger,
+        },
+        overlay: OverlayColours {
+            page: dark.page,
+            backdrop_muted: theme::BACKDROP_MUTED,
+            ink: dark.ink,
+            ink_soft: dark.ink_soft,
+            rule: dark.rule,
+            accent: dark.accent,
+            on_accent: dark.on_accent,
+        },
+        sizes: Sizes {
+            caption: theme::CAPTION.px,
+            label: theme::LABEL.px,
+            ui: theme::UI.px,
+            body: theme::BODY.px,
+            title: theme::TITLE.px,
+            display: theme::DISPLAY.px,
+            micro: theme::MICRO.px,
+            radius: theme::RADIUS,
+            radius_plate: theme::RADIUS_PLATE,
+            control_large: theme::CONTROL_LARGE,
+        },
+        fonts: Some(Fonts {
+            regular: theme::fonts::GEIST_REGULAR,
+            medium: theme::fonts::GEIST_MEDIUM,
+            semibold: theme::fonts::GEIST_SEMIBOLD,
+            mono: theme::fonts::GEIST_MONO,
+        }),
+    });
+}

crates/horizon-client/src/lib.rs

@@ -6,6 +6,7 @@ extern crate self as horizon_client;
 pub use horizon_client_lib::*;
 pub mod entry;
 pub mod game;
+mod horizon_look;
 pub mod mod_api;
 
 #[cfg(test)]

crates/horizon-client/src/no_resources.rs

@@ -46,11 +46,11 @@ impl NoResources {
         let x = ((ui.w - width) / 2.0).round();
         let lines: Vec<Vec<String>> = PARAGRAPHS
             .iter()
-            .map(|p| wrap(ui, Face::Regular, BODY, p, width))
+            .map(|p| wrap(ui, Face::Regular, body(), p, width))
             .collect();
         let text_h = lines.iter().map(|l| l.len() as f32 * LINE).sum::<f32>()
             + (lines.len() - 1) as f32 * PARAGRAPH_GAP;
-        let height = TITLE_LINE + 16.0 + text_h + 28.0 + CONTROL + 20.0 + SMALL_LINE;
+        let height = TITLE_LINE + 16.0 + text_h + 28.0 + control() + 20.0 + SMALL_LINE;
         let y = ((ui.h - height) / 2.0).max(24.0).round();
         let buttons_y = y + TITLE_LINE + 16.0 + text_h + 28.0;
         let mut buttons = Vec::new();
@@ -59,7 +59,7 @@ impl NoResources {
             ("Download the launcher", Action::Download),
             ("Quit", Action::Quit),
         ] {
-            let w = (ui.measure(Face::Medium, BUTTON_TEXT, label) + 40.0).round();
+            let w = (ui.measure(Face::Medium, button_text(), label) + 40.0).round();
             buttons.push(Button {
                 label,
                 action,
@@ -80,21 +80,29 @@ impl NoResources {
 
     pub fn draw(&self, ui: &mut Ui) {
         let layout = self.layout(ui);
-        ui.rounded(0.0, 0.0, ui.w, ui.h, 0.0, color::BG);
+        ui.rounded(0.0, 0.0, ui.w, ui.h, 0.0, color::bg());
         let mut y = layout.y;
         ui.text_line(
             Face::Medium,
-            TITLE_SIZE,
+            title_size(),
             TITLE_LINE,
             layout.x,
             y,
-            color::TEXT,
+            color::text(),
             TITLE,
         );
         y += TITLE_LINE + 16.0;
         for paragraph in &layout.lines {
             for line in paragraph {
-                ui.text_line(Face::Regular, BODY, LINE, layout.x, y, color::TEXT, line);
+                ui.text_line(
+                    Face::Regular,
+                    body(),
+                    LINE,
+                    layout.x,
+                    y,
+                    color::text(),
+                    line,
+                );
                 y += LINE;
             }
             y += PARAGRAPH_GAP;
@@ -102,20 +110,20 @@ impl NoResources {
         for button in &layout.buttons {
             let hovered = button.contains(ui.cursor);
             let (plate, ink) = match (button.action, hovered) {
-                (Action::Download, false) => (color::ACCENT, color::ON_ACCENT),
+                (Action::Download, false) => (color::accent(), color::on_accent()),
                 (Action::Download, true) => {
-                    (color::with_alpha(color::ACCENT, 0.85), color::ON_ACCENT)
+                    (color::with_alpha(color::accent(), 0.85), color::on_accent())
                 }
-                (Action::Quit, false) => (color::RAISED, color::TEXT),
-                (Action::Quit, true) => (color::HOVER, color::TEXT),
+                (Action::Quit, false) => (color::raised(), color::text()),
+                (Action::Quit, true) => (color::hover(), color::text()),
             };
-            let h = CONTROL;
+            let h = control();
             ui.rounded(button.x, button.y, button.w, h, h / 2.0, plate);
-            let lw = ui.measure(Face::Medium, BUTTON_TEXT, button.label);
+            let lw = ui.measure(Face::Medium, button_text(), button.label);
             let lx = button.x + ((button.w - lw) / 2.0).round();
             ui.text_line(
                 Face::Medium,
-                BUTTON_TEXT,
+                button_text(),
                 h,
                 lx,
                 button.y,
@@ -123,11 +131,11 @@ impl NoResources {
                 button.label,
             );
         }
-        let small_y = layout.buttons[0].y + CONTROL + 20.0;
+        let small_y = layout.buttons[0].y + control() + 20.0;
         for (i, line) in wrap(
             ui,
             Face::Regular,
-            ui_theme::SMALL,
+            ui_theme::small(),
             &self.looked_in,
             layout.width,
         )
@@ -137,11 +145,11 @@ impl NoResources {
             let line_y = small_y + i as f32 * SMALL_LINE;
             ui.text_line(
                 Face::Regular,
-                ui_theme::SMALL,
+                ui_theme::small(),
                 SMALL_LINE,
                 layout.x,
                 line_y,
-                color::MUTED,
+                color::muted(),
                 line,
             );
         }
@@ -157,14 +165,22 @@ impl NoResources {
     }
 }
 
-const TITLE_SIZE: f32 = horizon_theme::TITLE.px;
+fn title_size() -> f32 {
+    ui_theme::sizes().title
+}
 const TITLE_LINE: f32 = 40.0;
-const BODY: f32 = horizon_theme::BODY.px;
+fn body() -> f32 {
+    ui_theme::sizes().body
+}
 const LINE: f32 = 24.0;
 const PARAGRAPH_GAP: f32 = 10.0;
-const BUTTON_TEXT: f32 = horizon_theme::UI.px;
+fn button_text() -> f32 {
+    ui_theme::sizes().ui
+}
 const SMALL_LINE: f32 = 18.0;
-const CONTROL: f32 = horizon_theme::CONTROL_LARGE;
+fn control() -> f32 {
+    ui_theme::sizes().control_large
+}
 
 struct Layout {
     x: f32,
@@ -184,7 +200,7 @@ struct Button {
 
 impl Button {
     fn contains(&self, (cx, cy): (f32, f32)) -> bool {
-        cx >= self.x && cx < self.x + self.w && cy >= self.y && cy < self.y + CONTROL
+        cx >= self.x && cx < self.x + self.w && cy >= self.y && cy < self.y + control()
     }
 }
 
@@ -232,7 +248,7 @@ mod tests {
         for size in [[1280, 720], [800, 600], [2560, 1440]] {
             let (download, quit, density) = with_ui(size, (0.0, 0.0), |ui| {
                 let layout = screen.layout(ui);
-                let center = |b: &Button| (b.x + b.w / 2.0, b.y + CONTROL / 2.0);
+                let center = |b: &Button| (b.x + b.w / 2.0, b.y + control() / 2.0);
                 (
                     center(&layout.buttons[0]),
                     center(&layout.buttons[1]),
@@ -255,7 +271,7 @@ mod tests {
                 let layout = screen.layout(ui);
                 let last = layout.buttons.last().unwrap();
                 assert!(
-                    last.x + last.w <= ui.w && last.y + CONTROL <= ui.h,
+                    last.x + last.w <= ui.w && last.y + control() <= ui.h,
                     "{size:?}"
                 );
             });
@@ -266,10 +282,10 @@ mod tests {
     fn text_wraps_within_the_column_and_keeps_every_word() {
         with_ui([1280, 720], (0.0, 0.0), |ui| {
             for paragraph in PARAGRAPHS {
-                let lines = wrap(ui, Face::Regular, BODY, paragraph, 300.0);
+                let lines = wrap(ui, Face::Regular, body(), paragraph, 300.0);
                 assert!(lines.len() > 1, "{paragraph}");
                 for line in &lines {
-                    assert!(ui.measure(Face::Regular, BODY, line) <= 300.0, "{line}");
+                    assert!(ui.measure(Face::Regular, body(), line) <= 300.0, "{line}");
                 }
                 assert_eq!(lines.join(" "), paragraph);
             }

crates/horizon-client/src/osk.rs

@@ -293,16 +293,16 @@ impl Keyboard {
             y0 - 12.0,
             width + 24.0,
             height,
-            ui_theme::RADIUS_PLATE,
-            color::with_alpha(color::BG, 0.94),
+            ui_theme::radius_plate(),
+            color::with_alpha(color::bg(), 0.94),
         );
         ui.border(
             x0 - 12.0,
             y0 - 12.0,
             width + 24.0,
             height,
-            ui_theme::RADIUS_PLATE,
-            color::BORDER,
+            ui_theme::radius_plate(),
+            color::border(),
         );
         for (r, row) in self.rows().iter().enumerate() {
             let y = y0 + r as f32 * (KEY_H + GAP);
@@ -314,13 +314,13 @@ impl Keyboard {
                 let lit = matches!(key, Key::Shift) && (self.shift || self.caps)
                     || matches!(key, Key::Layer) && self.symbols;
                 let (plate, ink) = if focused {
-                    (color::ACCENT, color::ON_ACCENT)
+                    (color::accent(), color::on_accent())
                 } else if lit {
-                    (color::HOVER, color::TEXT)
+                    (color::hover(), color::text())
                 } else {
-                    (color::RAISED, color::TEXT)
+                    (color::raised(), color::text())
                 };
-                ui.rounded(x, y, w, KEY_H, ui_theme::RADIUS, plate);
+                ui.rounded(x, y, w, KEY_H, ui_theme::radius(), plate);
                 let label = match key {
                     Key::Char(ch) => self.letter(*ch),
                     Key::Shift if self.caps => "CAPS".into(),
@@ -331,10 +331,10 @@ impl Keyboard {
                     Key::Backspace => tr("horizon.osk.delete", "Delete"),
                     Key::Done => tr("gui.done", "Done"),
                 };
-                let lw = ui.measure(Face::Medium, ui_theme::BODY, &label);
+                let lw = ui.measure(Face::Medium, ui_theme::body(), &label);
                 ui.text_line(
                     Face::Medium,
-                    ui_theme::BODY,
+                    ui_theme::body(),
                     KEY_H,
                     x + ((w - lw) / 2.0).round(),
                     y,
@@ -359,10 +359,10 @@ impl Keyboard {
             .collect();
         ui.text_centered(
             Face::Regular,
-            ui_theme::SMALL,
+            ui_theme::small(),
             x0 + width / 2.0,
             y0 + 5.0 * (KEY_H + GAP) + 2.0,
-            color::MUTED,
+            color::muted(),
             &line.join("   "),
         );
     }

crates/horizon-client/src/studio/timeline_ui.rs

@@ -408,7 +408,7 @@ impl TimelineUi {
             let tx = start_x + sec * px_per_sec;
             if tx <= start_x + w {
                 // Major tick line
-                style::fill(batch, atlas, [tx, y + 8.0, 1.0, 8.0], style::HEAD_RULE);
+                style::fill(batch, atlas, [tx, y + 8.0, 1.0, 8.0], style::head_rule());
                 // Label every 2 or 5 seconds depending on width
                 let is_labeled = if total_secs > 60.0 {
                     (sec as u32).is_multiple_of(10)
@@ -424,7 +424,7 @@ impl TimelineUi {
                         "horizon.studio.timeline.seconds",
                         &[Text::literal(seconds)],
                     );
-                    batch.text_styled(atlas, &label, tx + 2.0, y + 1.0, style::SOFT, true);
+                    batch.text_styled(atlas, &label, tx + 2.0, y + 1.0, style::soft(), true);
                 }
             }
             sec += sec_step;
@@ -459,7 +459,7 @@ impl TimelineUi {
         // Base lane well
         let lane_rect = [start_x, y, track_w, bar_h];
         style::fill(batch, atlas, lane_rect, 0xFF14_171F);
-        style::ring(batch, atlas, lane_rect, style::ROW_RULE);
+        style::ring(batch, atlas, lane_rect, style::row_rule());
 
         let total_dur = self.duration_ms.max(1) as f32;
 
@@ -514,7 +514,7 @@ impl TimelineUi {
                     &scene_title,
                     seg_x + 5.0,
                     y + 5.0,
-                    style::MUTED,
+                    style::muted(),
                     true,
                 );
             }
@@ -577,7 +577,7 @@ impl TimelineUi {
         let px = start_x + norm * track_w;
 
         // Scrubber line from ruler through bottom of tracks
-        style::fill(batch, atlas, [px - 1.0, y, 2.0, h], style::ACCENT);
+        style::fill(batch, atlas, [px - 1.0, y, 2.0, h], style::accent());
 
         // Inverted triangle marker at ruler top
         let tri_color = style::WHITE;

crates/horizon-client/src/studio/topbar.rs

@@ -178,7 +178,7 @@ impl TopBarUi {
                 );
             }
             let color = if open {
-                style::ACCENT
+                style::accent()
             } else if hovered {
                 style::WHITE
             } else {
@@ -220,7 +220,7 @@ impl TopBarUi {
             if pause_hovered {
                 style::WHITE
             } else {
-                style::MUTED
+                style::muted()
             },
             true,
         );
@@ -339,7 +339,11 @@ impl TopBarUi {
                 &Text::translate(key, &[]),
                 x + 8.0,
                 y + 6.0,
-                if hovered { style::WHITE } else { style::MUTED },
+                if hovered {
+                    style::WHITE
+                } else {
+                    style::muted()
+                },
                 true,
             );
             if !shortcut.is_empty() {
@@ -350,7 +354,7 @@ impl TopBarUi {
                     &shortcut,
                     x + menu_width - shortcut_width - 8.0,
                     y + 6.0,
-                    style::SOFT,
+                    style::soft(),
                     true,
                 );
             }

crates/horizon-client/src/ui_theme.rs

@@ -1,6 +1,6 @@
-//! The design system's widgets drawn in the game (`crates/horizon-theme`:
-//! palette, type scale, radii, control sizes, motion and the bundled fonts;
-//! `docs/design-system.md`). Every menu is vanilla's (`ui`); what is left
+//! The design system's widgets drawn in the game: palette, type scale, radii,
+//! control sizes and fonts from `menu_style`, given at startup (in the official
+//! game `crates/horizon-theme`, `docs/design-system.md`). Every menu is vanilla's (`ui`); what is left
 //! here draws Horizon's own overlays that vanilla has no screen for: the
 //! on-screen keyboard a controller types with (`osk`), plus the
 //! `horizon.txt` preferences.
@@ -39,44 +39,76 @@ pub(crate) fn set_preference(dir: &Path, key: &str, value: Option<&str>) {
     let _ = std::fs::write(dir.join("horizon.txt"), out);
 }
 
-/// The dark palette (`horizon_theme::DARK`) in the HUD's colour encoding, plus the
+/// The overlays' palette (`menu_style`) in the HUD's colour encoding, plus the
 /// translucent plates the overlays draw over the game.
 pub(crate) mod color {
-    use horizon_theme::DARK as P;
-    pub const fn hex(c: u32, a: u8) -> u32 {
-        (a as u32) << 24 | (c & 0xff) << 16 | (c >> 8 & 0xff) << 8 | (c >> 16 & 0xff)
+    use horizon_client_render::menu_style::{self, OverlayColours};
+    pub use menu_style::hud_colour as hex;
+    fn p() -> &'static OverlayColours {
+        &menu_style::get().overlay
     }
     /// The page, under every veil.
-    pub const BG: u32 = hex(P.page, 255);
+    pub fn bg() -> u32 {
+        hex(p().page, 255)
+    }
     /// Hover plates, secondary buttons, fields, the segmented track: the
     /// dark palette's soft plate, as ink over the veil so the plates read the
     /// same over any backdrop (over the page colour they are `plate_soft`).
-    pub const RAISED: u32 = hex(P.ink, 20);
+    pub fn raised() -> u32 {
+        hex(p().ink, 20)
+    }
     /// Pressed plates and a switch that is off (`plate`, the same way).
-    pub const HOVER: u32 = hex(P.ink, 36);
+    pub fn hover() -> u32 {
+        hex(p().ink, 36)
+    }
     /// One-pixel rules between rows, slider tracks.
-    pub const BORDER: u32 = hex(P.rule, 255);
+    pub fn border() -> u32 {
+        hex(p().rule, 255)
+    }
     /// Text and selection (`ink`).
-    pub const TEXT: u32 = hex(P.ink, 255);
+    pub fn text() -> u32 {
+        hex(p().ink, 255)
+    }
     /// Values and secondary text (`ink_soft`).
-    pub const MUTED: u32 = hex(P.ink_soft, 255);
-    pub const ACCENT: u32 = hex(P.accent, 255);
-    pub const ON_ACCENT: u32 = hex(P.on_accent, 255);
+    pub fn muted() -> u32 {
+        hex(p().ink_soft, 255)
+    }
+    pub fn accent() -> u32 {
+        hex(p().accent, 255)
+    }
+    pub fn on_accent() -> u32 {
+        hex(p().on_accent, 255)
+    }
     pub(crate) fn with_alpha(c: u32, a: f32) -> u32 {
         let base = (c >> 24) as f32;
         (c & 0x00ff_ffff) | ((base * a.clamp(0.0, 1.0)).round() as u32) << 24
     }
 }
 
-/// The launcher's type scale and shapes (`horizon_theme`), in dp.
-pub(crate) const SMALL: f32 = horizon_theme::CAPTION.px;
-pub(crate) const BODY: f32 = horizon_theme::LABEL.px;
-/// The boot screen's wordmark (`DISPLAY`) and console lines (`MICRO`).
-pub(crate) const DISPLAY: f32 = horizon_theme::DISPLAY.px;
-pub(crate) const MICRO: f32 = horizon_theme::MICRO.px;
-/// Fields; plates (hover rows, selection); pills (buttons, segments).
-pub(crate) const RADIUS: f32 = horizon_theme::RADIUS;
-pub(crate) const RADIUS_PLATE: f32 = horizon_theme::RADIUS_PLATE;
+/// The type scale and shapes (`menu_style`), in dp.
+pub(crate) fn sizes() -> &'static horizon_client_render::menu_style::Sizes {
+    &horizon_client_render::menu_style::get().sizes
+}
+pub(crate) fn small() -> f32 {
+    sizes().caption
+}
+pub(crate) fn body() -> f32 {
+    sizes().label
+}
+/// The boot screen's wordmark (`display`) and console lines (`micro`).
+fn display() -> f32 {
+    sizes().display
+}
+fn micro() -> f32 {
+    sizes().micro
+}
+/// Fields; plates (hover rows, selection).
+pub(crate) fn radius() -> f32 {
+    sizes().radius
+}
+pub(crate) fn radius_plate() -> f32 {
+    sizes().radius_plate
+}
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub(crate) enum Face {
@@ -87,20 +119,34 @@ pub(crate) enum Face {
     /// Counts, timestamps and the boot screen's console lines.
     Mono,
 }
+#[cfg(not(test))]
+const TEST_FONTS: Option<horizon_client_render::menu_style::Fonts> = None;
+#[cfg(test)]
+const TEST_FONTS: Option<horizon_client_render::menu_style::Fonts> =
+    Some(horizon_client_render::menu_style::Fonts {
+        regular: horizon_theme::fonts::GEIST_REGULAR,
+        medium: horizon_theme::fonts::GEIST_MEDIUM,
+        semibold: horizon_theme::fonts::GEIST_SEMIBOLD,
+        mono: horizon_theme::fonts::GEIST_MONO,
+    });
 struct Fonts {
     faces: [FontRef<'static>; 4],
 }
 impl Fonts {
-    fn load() -> Self {
-        let f = |b: &'static [u8]| FontRef::try_from_slice(b).expect("bundled font");
-        Self {
+    /// The faces given in `menu_style`; none given, none (unit tests take the design system's).
+    fn load() -> Option<Self> {
+        let given = horizon_client_render::menu_style::get()
+            .fonts
+            .or(TEST_FONTS)?;
+        let f = |b: &'static [u8]| FontRef::try_from_slice(b).expect("given font");
+        Some(Self {
             faces: [
-                f(horizon_theme::fonts::GEIST_REGULAR),
-                f(horizon_theme::fonts::GEIST_MEDIUM),
-                f(horizon_theme::fonts::GEIST_SEMIBOLD),
-                f(horizon_theme::fonts::GEIST_MONO),
+                f(given.regular),
+                f(given.medium),
+                f(given.semibold),
+                f(given.mono),
             ],
-        }
+        })
     }
     fn face(&self, f: Face) -> &FontRef<'static> {
         &self.faces[f as usize]
@@ -142,7 +188,8 @@ struct Cached {
 }
 /// Glyphs and corner masks rasterized into the atlas region `horizon/ui-text`.
 struct Cache {
-    fonts: Fonts,
+    /// None: no fonts were given, and text draws nothing.
+    fonts: Option<Fonts>,
     entries: HashMap<Key, Cached>,
     shelf: (u32, u32, u32),
     pending: Vec<crate::font::Patch>,
@@ -230,9 +277,16 @@ impl Cache {
         if let Some(c) = self.entries.get(&key) {
             return *c;
         }
-        let scale = self.fonts.scale(face, f32::from(size) / 4.0);
+        let Some(fonts) = &self.fonts else {
+            return Cached {
+                rect: None,
+                left: 0.0,
+                top: 0.0,
+            };
+        };
+        let scale = fonts.scale(face, f32::from(size) / 4.0);
         let glyph = id.with_scale_and_position(scale, ab_glyph::point(0.0, 0.0));
-        let made = match self.fonts.face(face).outline_glyph(glyph) {
+        let made = match fonts.face(face).outline_glyph(glyph) {
             Some(outline) => {
                 let b = outline.px_bounds();
                 let (w, h) = (b.width() as u32, b.height() as u32);
@@ -459,14 +513,17 @@ impl<'a> Ui<'a> {
         let atlas = self.atlas;
         let gui = self.scale;
         with_cache(atlas, |c| {
-            let scale = c.fonts.scale(face, px);
+            let Some(fonts) = &c.fonts else {
+                return (0.0, 0.0, 0.0, Vec::new());
+            };
+            let scale = fonts.scale(face, px);
             let (ascent, descent) = {
-                let f = c.fonts.face(face).as_scaled(scale);
+                let f = fonts.face(face).as_scaled(scale);
                 (f.ascent(), f.descent())
             };
             let chars: Vec<(char, Option<crate::font::Glyph>)> = unformatted(text)
                 .map(|ch| {
-                    let pack = (!ch.is_whitespace() && c.fonts.face(face).glyph_id(ch).0 == 0)
+                    let pack = (!ch.is_whitespace() && fonts.face(face).glyph_id(ch).0 == 0)
                         .then(|| atlas.font.glyph(ch))
                         // The pack lacks it too (its missing glyph): Geist's box, like vanilla's.
                         .filter(|g| g.rect.is_some() || g.right <= 0.0);
@@ -491,7 +548,10 @@ impl<'a> Ui<'a> {
                     continue;
                 }
                 let (id, advance, kern) = {
-                    let font = c.fonts.face(face);
+                    let Some(fonts) = &c.fonts else {
+                        break;
+                    };
+                    let font = fonts.face(face);
                     let id = font.glyph_id(ch);
                     let f = font.as_scaled(scale);
                     (id, f.h_advance(id), prev.map_or(0.0, |p| f.kern(p, id)))
@@ -606,8 +666,8 @@ pub fn draw_boot(atlas: &HudAtlas, batch: &mut HudBatch, logs: &[String]) {
 /// The wordmark with its tagline, centred.
 fn wordmark(atlas: &HudAtlas, batch: &mut HudBatch) {
     let mut ui = Ui::new(atlas, batch, (0.0, 0.0));
-    let size = (ui.w / 16.0).clamp(DISPLAY, 96.0);
-    let small = (size * 0.25).clamp(MICRO, 18.0);
+    let size = (ui.w / 16.0).clamp(display(), 96.0);
+    let small = (size * 0.25).clamp(micro(), 18.0);
     let block = size * 1.45 + small * 0.6 + small * 1.5;
     let top = (ui.h - block) / 2.0;
     ui.text_centered(Face::SemiBold, size, ui.w / 2.0, top, BOOT_TEXT, "Horizon");
@@ -629,7 +689,7 @@ pub fn draw_boot_log(atlas: &HudAtlas, batch: &mut HudBatch, logs: &[String]) {
         return;
     }
     let mut ui = Ui::new(atlas, batch, (0.0, 0.0));
-    let (size, line, pad) = (MICRO, MICRO * 1.5, 16.0);
+    let (size, line, pad) = (micro(), micro() * 1.5, 16.0);
     let max_w = ui.w / 2.0;
     let max_rows = (((ui.h - pad) / line) as usize).clamp(1, 24);
     let mut y = ui.h - pad - line;
@@ -696,7 +756,12 @@ mod tests {
         let atlas = HudAtlas::build(Path::new("/nonexistent/horizon-test-assets")).unwrap();
         reset_atlas();
         let draw = |cache: &mut Cache| {
-            let glyph = cache.fonts.face(Face::Regular).glyph_id('A');
+            let glyph = cache
+                .fonts
+                .as_ref()
+                .unwrap()
+                .face(Face::Regular)
+                .glyph_id('A');
             assert!(
                 cache
                     .glyph(&atlas, Face::Regular, glyph, 16.0)
@@ -782,7 +847,7 @@ mod tests {
         let lines = wrapping_lines(
             &ui,
             Face::Mono,
-            MICRO,
+            micro(),
             "the quick brown fox jumps over the lazy dog",
             90.0,
         );
@@ -790,7 +855,7 @@ mod tests {
         assert!(
             lines
                 .iter()
-                .all(|l| ui.measure(Face::Mono, MICRO, l) <= 90.0),
+                .all(|l| ui.measure(Face::Mono, micro(), l) <= 90.0),
             "every wrapped line fits"
         );
         assert_eq!(
@@ -812,7 +877,7 @@ mod tests {
     fn drawn(atlas: &HudAtlas, text: &str) -> (f32, Vec<([f32; 2], [f32; 2])>) {
         let mut batch = HudBatch::new([1280, 720]);
         let mut ui = Ui::new(atlas, &mut batch, (0.0, 0.0));
-        let w = ui.text_line(Face::Medium, BODY, 20.0, 10.0, 10.0, color::TEXT, text);
+        let w = ui.text_line(Face::Medium, body(), 20.0, 10.0, 10.0, color::text(), text);
         let quads = batch
             .vertices
             .iter()

tools/layers.json

@@ -95,7 +95,6 @@
     "horizon-client -> horizon-shaders",
     "horizon-client -> horizon-telemetry",
     "horizon-client -> horizon-theme",
-    "horizon-client-input -> horizon-theme",
     "horizon-client-lib -> horizon-anticheat",
     "horizon-client-lib -> horizon-bench",
     "horizon-client-lib -> horizon-chat-filter",
@@ -107,13 +106,11 @@
     "horizon-client-lib -> horizon-shader-api",
     "horizon-client-lib -> horizon-shaders",
     "horizon-client-lib -> horizon-telemetry",
-    "horizon-client-lib -> horizon-theme",
     "horizon-client-render -> horizon-cosmetics",
     "horizon-client-render -> horizon-hdr",
     "horizon-client-render -> horizon-optifine",
     "horizon-client-render -> horizon-polytone",
     "horizon-client-render -> horizon-shader-api",
-    "horizon-client-render -> horizon-shaders",
-    "horizon-client-render -> horizon-theme"
+    "horizon-client-render -> horizon-shaders"
   ]
 }