Remove eframe-specific system theme sync

crates/eframe/src/epi.rs

@@ -769,11 +769,6 @@ pub struct IntegrationInfo {
     #[cfg(target_arch = "wasm32")]
     pub web_info: WebInfo,
 
-    /// Does the OS use dark or light mode?
-    ///
-    /// `None` means "don't know".
-    pub system_theme: Option<Theme>,
-
     /// Seconds of cpu usage (in seconds) on the previous frame.
     ///
     /// This includes [`App::update`] as well as rendering (except for vsync waiting).

crates/eframe/src/native/epi_integration.rs

@@ -7,7 +7,7 @@ use winit::event_loop::EventLoopWindowTarget;
 
 use raw_window_handle::{HasDisplayHandle as _, HasWindowHandle as _};
 
-use egui::{DeferredViewportUiCallback, NumExt as _, Theme, ViewportBuilder, ViewportId, Visuals};
+use egui::{DeferredViewportUiCallback, NumExt as _, ViewportBuilder, ViewportId};
 use egui_winit::{EventResponse, WindowSettings};
 
 use crate::epi;
@@ -162,7 +162,6 @@ pub struct EpiIntegration {
     close: bool,
 
     can_drag_window: bool,
-    follow_system_theme: bool,
     #[cfg(feature = "persistence")]
     persist_window: bool,
     app_icon_setter: super::app_icon::AppTitleIconSetter,
@@ -173,7 +172,6 @@ impl EpiIntegration {
     pub fn new(
         egui_ctx: egui::Context,
         window: &winit::window::Window,
-        system_theme: Option<Theme>,
         app_name: &str,
         native_options: &crate::NativeOptions,
         storage: Option<Box<dyn epi::Storage>>,
@@ -184,10 +182,7 @@ impl EpiIntegration {
         #[cfg(feature = "wgpu")] wgpu_render_state: Option<egui_wgpu::RenderState>,
     ) -> Self {
         let frame = epi::Frame {
-            info: epi::IntegrationInfo {
-                system_theme,
-                cpu_usage: None,
-            },
+            info: epi::IntegrationInfo { cpu_usage: None },
             storage,
             #[cfg(feature = "glow")]
             gl,
@@ -221,7 +216,6 @@ impl EpiIntegration {
             pending_full_output: Default::default(),
             close: false,
             can_drag_window: false,
-            follow_system_theme: native_options.follow_system_theme,
             #[cfg(feature = "persistence")]
             persist_window: native_options.persist_window,
             app_icon_setter,
@@ -277,11 +271,6 @@ impl EpiIntegration {
                 state: ElementState::Pressed,
                 ..
             } => self.can_drag_window = true,
-            WindowEvent::ThemeChanged(winit_theme) if self.follow_system_theme => {
-                let theme = theme_from_winit_theme(*winit_theme);
-                self.frame.info.system_theme = Some(theme);
-                self.egui_ctx.set_visuals(Visuals::theme(theme));
-            }
             _ => {}
         }
 
@@ -424,10 +413,3 @@ pub fn load_egui_memory(_storage: Option<&dyn epi::Storage>) -> Option<egui::Mem
     #[cfg(not(feature = "persistence"))]
     None
 }
-
-pub(crate) fn theme_from_winit_theme(theme: winit::window::Theme) -> Theme {
-    match theme {
-        winit::window::Theme::Dark => Theme::Dark,
-        winit::window::Theme::Light => Theme::Light,
-    }
-}

crates/eframe/src/native/glow_integration.rs

@@ -29,7 +29,7 @@ use winit::{
 use ahash::{HashMap, HashSet};
 use egui::{
     DeferredViewportUiCallback, ImmediateViewport, ViewportBuilder, ViewportClass, ViewportId,
-    ViewportIdMap, ViewportIdPair, ViewportInfo, ViewportOutput, Visuals,
+    ViewportIdMap, ViewportIdPair, ViewportInfo, ViewportOutput,
 };
 #[cfg(feature = "accesskit")]
 use egui_winit::accesskit_winit;
@@ -228,14 +228,11 @@ impl GlowWinitApp {
             }
         }
 
-        let system_theme =
-            winit_integration::system_theme(&glutin.window(ViewportId::ROOT), &self.native_options);
         let painter = Rc::new(RefCell::new(painter));
 
         let integration = EpiIntegration::new(
             egui_ctx,
             &glutin.window(ViewportId::ROOT),
-            system_theme,
             &self.app_name,
             &self.native_options,
             storage,
@@ -281,9 +278,6 @@ impl GlowWinitApp {
             }
         }
 
-        let theme = system_theme.unwrap_or(self.native_options.default_theme);
-        integration.egui_ctx.set_visuals(Visuals::theme(theme));
-
         if self
             .native_options
             .viewport

crates/eframe/src/native/wgpu_integration.rs

@@ -19,7 +19,6 @@ use ahash::{HashMap, HashSet, HashSetExt};
 use egui::{
     DeferredViewportUiCallback, FullOutput, ImmediateViewport, ViewportBuilder, ViewportClass,
     ViewportId, ViewportIdMap, ViewportIdPair, ViewportIdSet, ViewportInfo, ViewportOutput,
-    Visuals,
 };
 #[cfg(feature = "accesskit")]
 use egui_winit::accesskit_winit;
@@ -206,11 +205,9 @@ impl WgpuWinitApp {
 
         let wgpu_render_state = painter.render_state();
 
-        let system_theme = winit_integration::system_theme(&window, &self.native_options);
         let integration = EpiIntegration::new(
             egui_ctx.clone(),
             &window,
-            system_theme,
             &self.app_name,
             &self.native_options,
             storage,
@@ -256,9 +253,6 @@ impl WgpuWinitApp {
         }
         egui_winit.init_system_theme(&window);
 
-        let theme = system_theme.unwrap_or(self.native_options.default_theme);
-        egui_ctx.set_visuals(Visuals::theme(theme));
-
         let app_creator = std::mem::take(&mut self.app_creator)
             .expect("Single-use AppCreator has unexpectedly already been taken");
         let cc = CreationContext {

crates/eframe/src/native/winit_integration.rs

@@ -5,7 +5,7 @@ use winit::{
     window::{Window, WindowId},
 };
 
-use egui::{Theme, ViewportId};
+use egui::ViewportId;
 #[cfg(feature = "accesskit")]
 use egui_winit::accesskit_winit;
 
@@ -103,16 +103,6 @@ pub enum EventResult {
     Exit,
 }
 
-pub fn system_theme(window: &Window, options: &crate::NativeOptions) -> Option<Theme> {
-    if options.follow_system_theme {
-        window
-            .theme()
-            .map(super::epi_integration::theme_from_winit_theme)
-    } else {
-        None
-    }
-}
-
 /// Short and fast description of an event.
 /// Useful for logging and profiling.
 pub fn short_event_description(event: &winit::event::Event<UserEvent>) -> &'static str {

crates/eframe/src/web/app_runner.rs

@@ -1,4 +1,4 @@
-use egui::{TexturesDelta, Visuals};
+use egui::TexturesDelta;
 
 use crate::{epi, App};
 
@@ -38,18 +38,11 @@ impl AppRunner {
     ) -> Result<Self, String> {
         let painter = super::ActiveWebPainter::new(canvas_id, &web_options).await?;
 
-        let system_theme = if web_options.follow_system_theme {
-            super::system_theme()
-        } else {
-            None
-        };
-
         let info = epi::IntegrationInfo {
             web_info: epi::WebInfo {
                 user_agent: super::user_agent().unwrap_or_default(),
                 location: super::web_location(),
             },
-            system_theme,
             cpu_usage: None,
         };
         let storage = LocalStorage::default();
@@ -68,9 +61,6 @@ impl AppRunner {
             o.zoom_factor = 1.0;
         });
 
-        let theme = system_theme.unwrap_or(web_options.default_theme);
-        egui_ctx.set_visuals(Visuals::theme(theme));
-
         let cc = epi::CreationContext {
             egui_ctx: egui_ctx.clone(),
             integration_info: info.clone(),

crates/eframe/src/web/events.rs

@@ -1,4 +1,3 @@
-use egui::Visuals;
 use web_sys::EventTarget;
 
 use super::*;
@@ -368,8 +367,6 @@ pub(crate) fn install_color_scheme_change_event(runner_ref: &WebRunner) -> Resul
             "change",
             |event, runner| {
                 let theme = theme_from_dark_mode(event.matches());
-                runner.frame.info.system_theme = Some(theme);
-                runner.egui_ctx().set_visuals(Visuals::theme(theme));
                 runner.input.raw.system_theme = Some(theme);
                 runner.needs_repaint.repaint_asap();
             },

crates/eframe/src/web/web_runner.rs

@@ -63,8 +63,6 @@ impl WebRunner {
     ) -> Result<(), JsValue> {
         self.destroy();
 
-        let follow_system_theme = web_options.follow_system_theme;
-
         let text_agent = TextAgent::attach(self)?;
 
         let runner = AppRunner::new(canvas_id, web_options, app_creator, text_agent).await?;
@@ -82,10 +80,7 @@ impl WebRunner {
 
         {
             events::install_event_handlers(self)?;
-
-            if follow_system_theme {
-                events::install_color_scheme_change_event(self)?;
-            }
+            events::install_color_scheme_change_event(self)?;
 
             // The resize observer handles calling `request_animation_frame` to start the render loop.
             events::install_resize_observer(self)?;