render/app: display bit depth option (10-bit default, 8-bit optional)

Preferences gains a display-bit-depth combo stored in the config store;
at startup the app forwards it to gpui_wgpu via OAK_DISPLAY_BIT_DEPTH,
which prefers Rgb10a2Unorm for 10-bit presentation. Takes effect after
restart (noted in the dialog); i18n in all eight packs.

assets/i18n/de.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Renderer-Backend"
 "preferences.hwdecode.enable": "Hardwarebeschleunigte Videodekodierung (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Backend auswählen…"
+"preferences.bit_depth.label": "Anzeige-Bittiefe"
+"preferences.bit_depth.10bit": "10 Bit"
+"preferences.bit_depth.8bit": "8 Bit"
+"preferences.bit_depth.restart_hint": "Eine Änderung wird nach einem Neustart wirksam."
 "preferences.language": "Sprache"
 "preferences.language.placeholder": "Sprache auswählen…"
 "preferences.theme": "Design"

assets/i18n/en-US.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Renderer backend"
 "preferences.hwdecode.enable": "Hardware-accelerated video decoding (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Select a backend…"
+"preferences.bit_depth.label": "Display bit depth"
+"preferences.bit_depth.10bit": "10-bit"
+"preferences.bit_depth.8bit": "8-bit"
+"preferences.bit_depth.restart_hint": "A change takes effect after a restart."
 "preferences.language": "Language"
 "preferences.language.placeholder": "Select a language…"
 "preferences.theme": "Theme"

assets/i18n/es.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Motor de renderizado"
 "preferences.hwdecode.enable": "Decodificación de vídeo acelerada por hardware (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Seleccionar un motor…"
+"preferences.bit_depth.label": "Profundidad de color de pantalla"
+"preferences.bit_depth.10bit": "10 bits"
+"preferences.bit_depth.8bit": "8 bits"
+"preferences.bit_depth.restart_hint": "El cambio surte efecto tras reiniciar."
 "preferences.language": "Idioma"
 "preferences.language.placeholder": "Seleccionar un idioma…"
 "preferences.theme": "Tema"

assets/i18n/fr.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Moteur de rendu"
 "preferences.hwdecode.enable": "Décodage vidéo accéléré par le matériel (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Sélectionner un moteur…"
+"preferences.bit_depth.label": "Profondeur de couleur de l'affichage"
+"preferences.bit_depth.10bit": "10 bits"
+"preferences.bit_depth.8bit": "8 bits"
+"preferences.bit_depth.restart_hint": "Le changement prend effet après un redémarrage."
 "preferences.language": "Langue"
 "preferences.language.placeholder": "Sélectionner une langue…"
 "preferences.theme": "Thème"

assets/i18n/ja.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "レンダラーバックエンド"
 "preferences.hwdecode.enable": "ハードウェアアクセラレーションによるビデオデコード(VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "バックエンドを選択…"
+"preferences.bit_depth.label": "表示ビット深度"
+"preferences.bit_depth.10bit": "10 ビット"
+"preferences.bit_depth.8bit": "8 ビット"
+"preferences.bit_depth.restart_hint": "変更は再起動後に反映されます。"
 "preferences.language": "言語"
 "preferences.language.placeholder": "言語を選択…"
 "preferences.theme": "テーマ"

assets/i18n/pt.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Backend do renderizador"
 "preferences.hwdecode.enable": "Decodificação de vídeo acelerada por hardware (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Selecionar um backend…"
+"preferences.bit_depth.label": "Profundidade de bits da tela"
+"preferences.bit_depth.10bit": "10 bits"
+"preferences.bit_depth.8bit": "8 bits"
+"preferences.bit_depth.restart_hint": "A alteração entra em vigor após reiniciar."
 "preferences.language": "Idioma"
 "preferences.language.placeholder": "Selecionar um idioma…"
 "preferences.theme": "Tema"

assets/i18n/ru.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "Бэкенд рендеринга"
 "preferences.hwdecode.enable": "Аппаратное декодирование видео (VideoToolbox / VA-API / NVDEC / D3D11VA)"
 "preferences.backend.placeholder": "Выберите бэкенд…"
+"preferences.bit_depth.label": "Глубина цвета экрана"
+"preferences.bit_depth.10bit": "10 бит"
+"preferences.bit_depth.8bit": "8 бит"
+"preferences.bit_depth.restart_hint": "Изменение вступит в силу после перезапуска."
 "preferences.language": "Язык"
 "preferences.language.placeholder": "Выберите язык…"
 "preferences.theme": "Тема"

assets/i18n/zh-CN.yaml

@@ -285,6 +285,10 @@
 "preferences.backend": "渲染后端"
 "preferences.hwdecode.enable": "硬件加速视频解码（VideoToolbox / VA-API / NVDEC / D3D11VA）"
 "preferences.backend.placeholder": "选择一个后端…"
+"preferences.bit_depth.label": "渲染色深"
+"preferences.bit_depth.10bit": "10 位"
+"preferences.bit_depth.8bit": "8 位"
+"preferences.bit_depth.restart_hint": "更改将在重启后生效。"
 "preferences.language": "语言"
 "preferences.language.placeholder": "选择语言…"
 "preferences.theme": "主题"

crates/oak-app/src/app.rs

@@ -3010,6 +3010,18 @@ fn run_with<E: AppEngine>(args: AppArgs) {
 			// SAFETY: single-threaded startup, before any window exists.
 			unsafe { std::env::set_var("OAK_MACOS_LAYER_COLORSPACE", "display") };
 		}
+		// Display bit depth: the wgpu window layer must pick the swapchain
+		// format before the surface is created, so surface the persisted
+		// choice the same way the colorspace tag is passed to the platform
+		// layer above. Read by gpui_wgpu as OAK_DISPLAY_BIT_DEPTH ("8" opts
+		// into the 8-bit pair; anything else requests 10-bit).
+		let bit_depth = oak_render::backend::DisplayBitDepth::from_config_string(
+			&crate::oakui::real::config_get_string(
+				oak_render::backend::CONFIG_KEY_DISPLAY_BIT_DEPTH,
+			),
+		);
+		// SAFETY: single-threaded startup, before any window exists.
+		unsafe { std::env::set_var("OAK_DISPLAY_BIT_DEPTH", bit_depth.to_config_string()) };
 		cx.init_colors();
 		let bounds = Bounds::centered(None, size(px(1600.0), px(900.0)), cx);
 		let initial = initial.clone();

crates/oak-app/src/dialogs.rs

@@ -54,6 +54,10 @@ use crate::oakui::real::{
 	DEFAULT_PREVIEW_WINDOW_FORWARD, DEFAULT_SNAPSHOT_INTERVAL_SEC, DEFAULT_TRANSITION_SEC,
 	EXPORT_FORMAT_MP4,
 };
+// The `DisplayBitDepth` config key lives with the format mapping it
+// drives (oak-render's backend); the preferences dropdown and the
+// window-layer consumer share the same key.
+use oak_render::backend::CONFIG_KEY_DISPLAY_BIT_DEPTH;
 
 // ---------------------------------------------------------------------------
 // Preferences
@@ -100,6 +104,10 @@ impl gpui::EventEmitter<PreferencesEvent> for PreferencesContent {}
 /// exit).
 pub struct PreferencesContent {
 	backend: Entity<ComboBox>,
+	/// The on-screen display bit depth (10-bit default, 8-bit fallback).
+	/// The swapchain format is fixed at surface creation, so a change
+	/// takes effect after a restart.
+	display_bit_depth: Entity<ComboBox>,
 	language: Entity<ComboBox>,
 	theme: Entity<ComboBox>,
 	cache_dir: Entity<PathField>,
@@ -162,6 +170,37 @@ impl PreferencesContent {
 			combo.set_selected(Some(backend_selected), cx)
 		});
 
+		// --- 渲染 Rendering: on-screen display bit depth ---------------------
+		// 10-bit is the default; 8-bit is the compatibility fallback. The
+		// swapchain format is chosen once at window/surface creation, so a
+		// change takes effect after a restart (see oak-render's
+		// `DisplayBitDepth::present_formats`).
+		let display_bit_depth = cx.new(|cx| {
+			let options = vec![
+				ComboBoxOption::new(0, i18n::tr("preferences.bit_depth.10bit")),
+				ComboBoxOption::new(1, i18n::tr("preferences.bit_depth.8bit")),
+			];
+			ComboBox::new(12, options, window, cx)
+		});
+		cx.subscribe(&display_bit_depth, |_this, _combo, event: &ComboBoxEvent, cx| {
+			if let ComboBoxEvent::Selected { value, .. } = event {
+				let depth = if *value == 1 { "8" } else { "10" };
+				config_set_string(CONFIG_KEY_DISPLAY_BIT_DEPTH, depth);
+				println!("[preferences] display bit depth → {depth}");
+			}
+			let _ = cx;
+		})
+		.detach();
+		let bit_depth_selected =
+			if config_get_string(CONFIG_KEY_DISPLAY_BIT_DEPTH) == "8" {
+				1
+			} else {
+				0
+			};
+		display_bit_depth.update(cx, |combo, cx| {
+			combo.set_selected(Some(bit_depth_selected), cx)
+		});
+
 		// --- 常规 General: language + theme --------------------------------
 		// Data-driven: one option per discovered language pack, labelled
 		// with the pack's own `language.name` — a newly dropped-in pack
@@ -494,6 +533,7 @@ impl PreferencesContent {
 
 		Self {
 			backend,
+			display_bit_depth,
 			language,
 			theme,
 			cache_dir,
@@ -855,6 +895,19 @@ impl Render for PreferencesContent {
 				i18n::tr("preferences.audio.input").into(),
 				self.audio_input.clone(),
 			))
+			// 渲染 Rendering: display bit depth (kept at the bottom of the list
+			// so the rows above stay inside the card's scroll viewport).
+			.child(form_row(
+				&colors,
+				i18n::tr("preferences.bit_depth.label").into(),
+				self.display_bit_depth.clone(),
+			))
+			.child(
+				div()
+					.text_color(colors.disabled)
+					.text_xs()
+					.child(i18n::tr("preferences.bit_depth.restart_hint")),
+			)
 			.child(
 				div()
 					.text_color(colors.disabled)

crates/oak-render/src/backend.rs

@@ -144,6 +144,74 @@ impl BackendKind {
 	}
 }
 
+/// The config-store key for the on-screen display bit depth ("10" or
+/// "8"). The window swapchain format is chosen once at surface creation,
+/// so a change takes effect after a restart.
+pub const CONFIG_KEY_DISPLAY_BIT_DEPTH: &str = "DisplayBitDepth";
+
+/// On-screen presentation bit depth, persisted under the
+/// `DisplayBitDepth` config key. The choice is user-visible: the
+/// preferences dialog exposes a 10-bit/8-bit dropdown, and it decides
+/// the formats the window layer presents with (see
+/// [`DisplayBitDepth::present_formats`]).
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum DisplayBitDepth {
+	/// 8-bit per channel (Bgra8/Rgba8 swapchain).
+	Bit8,
+	/// 10-bit per channel (RGB10A2 — the default; RGBA16F for HDR).
+	Bit10,
+}
+
+impl DisplayBitDepth {
+	/// Parse the settings string; unknown values yield the default 10-bit.
+	pub fn from_config_string(s: &str) -> DisplayBitDepth {
+		match s.trim() {
+			"8" => DisplayBitDepth::Bit8,
+			_ => DisplayBitDepth::Bit10,
+		}
+	}
+
+	/// The config-store value persisted for this depth.
+	pub fn to_config_string(self) -> &'static str {
+		match self {
+			DisplayBitDepth::Bit8 => "8",
+			DisplayBitDepth::Bit10 => "10",
+		}
+	}
+
+	/// Read the user's persisted choice through the oakcommon config C ABI
+	/// ("DisplayBitDepth").
+	pub fn from_user_config() -> DisplayBitDepth {
+		let configured =
+			crate::commonutil::config_get_string(None, CONFIG_KEY_DISPLAY_BIT_DEPTH)
+				.unwrap_or_default();
+		DisplayBitDepth::from_config_string(&configured)
+	}
+
+	/// The wgpu surface formats the window layer should present with, in
+	/// preference order (the platform picks the first the surface
+	/// supports). 10-bit prefers RGB10A2 with an RGBA16F (HDR) fallback;
+	/// 8-bit mirrors the engine's current default preference list.
+	///
+	/// The actual swapchain is configured by the window layer
+	/// (gpui_wgpu's surface setup intersects these with the surface
+	/// capabilities); this crate is headless and never creates a surface
+	/// itself, so the mapping is the format-selection contract the window
+	/// layer consumes at surface creation.
+	pub fn present_formats(self) -> &'static [wgpu::TextureFormat] {
+		match self {
+			DisplayBitDepth::Bit10 => &[
+				wgpu::TextureFormat::Rgb10a2Unorm,
+				wgpu::TextureFormat::Rgba16Float,
+			],
+			DisplayBitDepth::Bit8 => &[
+				wgpu::TextureFormat::Bgra8Unorm,
+				wgpu::TextureFormat::Rgba8Unorm,
+			],
+		}
+	}
+}
+
 /// A GPU-resident texture in the context registry.
 #[derive(Clone)]
 struct GpuTexture {
@@ -1312,6 +1380,43 @@ mod tests {
 		std::env::remove_var("OAK_RENDER_BACKEND");
 	}
 
+	#[test]
+	fn display_bit_depth_string_roundtrip() {
+		assert_eq!(DisplayBitDepth::from_config_string("8"), DisplayBitDepth::Bit8);
+		assert_eq!(
+			DisplayBitDepth::from_config_string("10"),
+			DisplayBitDepth::Bit10
+		);
+		// Unknown / missing → the 10-bit default.
+		assert_eq!(DisplayBitDepth::from_config_string(""), DisplayBitDepth::Bit10);
+		assert_eq!(
+			DisplayBitDepth::from_config_string("bogus"),
+			DisplayBitDepth::Bit10
+		);
+		assert_eq!(
+			DisplayBitDepth::from_config_string(DisplayBitDepth::Bit8.to_config_string()),
+			DisplayBitDepth::Bit8
+		);
+		assert_eq!(
+			DisplayBitDepth::from_config_string(DisplayBitDepth::Bit10.to_config_string()),
+			DisplayBitDepth::Bit10
+		);
+	}
+
+	#[test]
+	fn display_bit_depth_present_formats() {
+		// 10-bit → the 10-bit (RGB10A2) swapchain format, HDR float fallback.
+		assert_eq!(
+			DisplayBitDepth::Bit10.present_formats(),
+			&[wgpu::TextureFormat::Rgb10a2Unorm, wgpu::TextureFormat::Rgba16Float]
+		);
+		// 8-bit → the engine's current default preference list.
+		assert_eq!(
+			DisplayBitDepth::Bit8.present_formats(),
+			&[wgpu::TextureFormat::Bgra8Unorm, wgpu::TextureFormat::Rgba8Unorm]
+		);
+	}
+
 	#[test]
 	fn cpu_backend_has_no_adapter() {
 		assert!(GpuContext::create(BackendKind::Cpu).is_none());