Add Window::set_theme (#2553)

* Add `Window::set_theme`

* typo

* fix linux build

* fix wayland

* review changes

* update docs

* update changelog

* pin `image` dep

* suppport falling back to system default

* fix linux

* default to dark on macOS and x11

* fix `setAppearance` definition

* add macOS notes

* update docs

* Update CHANGELOG.md

Co-authored-by: Markus Siglreithmaier <m.siglreith@gmail.com>

* update doc

* Revert "pin `image` dep"

This reverts commit 7517f7c5065b4089ca146ce8799dab445ec32068.

* Update theme example with Window::set_theme

* Fix Window::theme getter on macOS

Co-authored-by: Markus Siglreithmaier <m.siglreith@gmail.com>
Co-authored-by: Mads Marquart <mads@marquart.dk>

CHANGELOG.md

@@ -8,7 +8,9 @@ And please only add new entries to the top of this list, right below the `# Unre
 
 # Unreleased
 
-- On Windows, revert window background to an empty brush to avoid white flashes when changing scaling
+- On Windows, macOS, X11 and Wayland, add `Window::set_theme`.
+- **Breaking:** Remove `WindowExtWayland::wayland_set_csd_theme` and `WindowBuilderExtX11::with_gtk_theme_variant`.
+- On Windows, revert window background to an empty brush to avoid white flashes when changing scaling.
 - **Breaking:** Removed `Window::set_always_on_top` and related APIs in favor of `Window::set_window_level`.
 - On Windows, MacOS and X11, add always on bottom APIs.
 - On Windows, fix the value in `MouseButton::Other`.

examples/theme.rs

@@ -2,7 +2,7 @@
 
 use simple_logger::SimpleLogger;
 use winit::{
-    event::{Event, WindowEvent},
+    event::{ElementState, Event, KeyboardInput, VirtualKeyCode, WindowEvent},
     event_loop::{ControlFlow, EventLoop},
     window::{Theme, WindowBuilder},
 };
@@ -18,6 +18,10 @@ fn main() {
         .unwrap();
 
     println!("Initial theme: {:?}", window.theme());
+    println!("debugging keys:");
+    println!("  (A) Automatic theme");
+    println!("  (L) Light theme");
+    println!("  (D) Dark theme");
 
     event_loop.run(move |event, _, control_flow| {
         *control_flow = ControlFlow::Wait;
@@ -34,6 +38,33 @@ fn main() {
             } if window_id == window.id() => {
                 println!("Theme is changed: {:?}", theme)
             }
+            Event::WindowEvent {
+                event:
+                    WindowEvent::KeyboardInput {
+                        input:
+                            KeyboardInput {
+                                virtual_keycode: Some(key),
+                                state: ElementState::Pressed,
+                                ..
+                            },
+                        ..
+                    },
+                ..
+            } => match key {
+                VirtualKeyCode::A => {
+                    println!("Theme was: {:?}", window.theme());
+                    window.set_theme(None);
+                }
+                VirtualKeyCode::L => {
+                    println!("Theme was: {:?}", window.theme());
+                    window.set_theme(Some(Theme::Light));
+                }
+                VirtualKeyCode::D => {
+                    println!("Theme was: {:?}", window.theme());
+                    window.set_theme(Some(Theme::Dark));
+                }
+                _ => (),
+            },
             _ => (),
         }
     });

src/platform/wayland.rs

@@ -88,14 +88,6 @@ pub trait WindowExtWayland {
     ///
     /// The pointer will become invalid when the [`Window`] is destroyed.
     fn wayland_display(&self) -> Option<*mut raw::c_void>;
-
-    /// Updates [`Theme`] of window decorations.
-    ///
-    /// You can also use `WINIT_WAYLAND_CSD_THEME` env variable to set the theme.
-    /// Possible values for env variable are: "dark" and light".
-    ///
-    /// When unspecified a theme is automatically selected.
-    fn wayland_set_csd_theme(&self, config: Theme);
 }
 
 impl WindowExtWayland for Window {
@@ -116,16 +108,6 @@ impl WindowExtWayland for Window {
             _ => None,
         }
     }
-
-    #[inline]
-    fn wayland_set_csd_theme(&self, theme: Theme) {
-        #[allow(clippy::single_match)]
-        match self.window {
-            LinuxWindow::Wayland(ref w) => w.set_csd_theme(theme),
-            #[cfg(feature = "x11")]
-            _ => (),
-        }
-    }
 }
 
 /// Additional methods on [`WindowBuilder`] that are specific to Wayland.

src/platform/x11.rs

@@ -190,9 +190,6 @@ pub trait WindowBuilderExtX11 {
     /// Build window with `_NET_WM_WINDOW_TYPE` hints; defaults to `Normal`. Only relevant on X11.
     fn with_x11_window_type(self, x11_window_type: Vec<XWindowType>) -> Self;
 
-    /// Build window with `_GTK_THEME_VARIANT` hint set to the specified value. Currently only relevant on X11.
-    fn with_gtk_theme_variant(self, variant: String) -> Self;
-
     /// Build window with base size hint. Only implemented on X11.
     ///
     /// ```
@@ -248,12 +245,6 @@ impl WindowBuilderExtX11 for WindowBuilder {
         self
     }
 
-    #[inline]
-    fn with_gtk_theme_variant(mut self, variant: String) -> Self {
-        self.platform_specific.gtk_theme_variant = Some(variant);
-        self
-    }
-
     #[inline]
     fn with_base_size<S: Into<Size>>(mut self, base_size: S) -> Self {
         self.platform_specific.base_size = Some(base_size.into());

src/platform_impl/android/mod.rs

@@ -1041,6 +1041,8 @@ impl Window {
         self.app.content_rect()
     }
 
+    pub fn set_theme(&self, _theme: Option<Theme>) {}
+
     pub fn theme(&self) -> Option<Theme> {
         None
     }

src/platform_impl/ios/window.rs

@@ -348,6 +348,11 @@ impl Inner {
         None
     }
 
+    #[inline]
+    pub fn set_theme(&self, _theme: Option<Theme>) {
+        warn!("`Window::set_theme` is ignored on iOS");
+    }
+
     pub fn title(&self) -> String {
         warn!("`Window::title` is ignored on iOS");
         String::new()

src/platform_impl/linux/mod.rs

@@ -100,8 +100,6 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub override_redirect: bool,
     #[cfg(feature = "x11")]
     pub x11_window_types: Vec<XWindowType>,
-    #[cfg(feature = "x11")]
-    pub gtk_theme_variant: Option<String>,
 }
 
 impl Default for PlatformSpecificWindowBuilderAttributes {
@@ -120,8 +118,6 @@ impl Default for PlatformSpecificWindowBuilderAttributes {
             override_redirect: false,
             #[cfg(feature = "x11")]
             x11_window_types: vec![XWindowType::Normal],
-            #[cfg(feature = "x11")]
-            gtk_theme_variant: None,
         }
     }
 }
@@ -585,6 +581,11 @@ impl Window {
         x11_or_wayland!(match self; Window(window) => window.raw_display_handle())
     }
 
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        x11_or_wayland!(match self; Window(window) => window.set_theme(theme))
+    }
+
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         x11_or_wayland!(match self; Window(window) => window.theme())

src/platform_impl/linux/wayland/window/mod.rs

@@ -439,11 +439,6 @@ impl Window {
         self.decorated.load(Ordering::Relaxed)
     }
 
-    #[inline]
-    pub fn set_csd_theme(&self, theme: Theme) {
-        self.send_request(WindowRequest::CsdThemeVariant(theme));
-    }
-
     #[inline]
     pub fn set_minimized(&self, minimized: bool) {
         // You can't unminimize the window on Wayland.
@@ -620,6 +615,11 @@ impl Window {
         self.event_loop_awakener.ping();
     }
 
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        self.send_request(WindowRequest::Theme(theme));
+    }
+
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         None

src/platform_impl/linux/wayland/window/shim.rs

@@ -59,9 +59,6 @@ pub enum WindowRequest {
     /// Request decorations change.
     Decorate(bool),
 
-    /// Request decorations change.
-    CsdThemeVariant(Theme),
-
     /// Make the window resizeable.
     Resizeable(bool),
 
@@ -96,6 +93,9 @@ pub enum WindowRequest {
 
     /// Window should be closed.
     Close,
+
+    /// Change window theme.
+    Theme(Option<Theme>),
 }
 
 // The window update comming from the compositor.
@@ -464,15 +464,6 @@ pub fn handle_window_requests(winit_state: &mut WinitState) {
                     let window_request = window_user_requests.get_mut(window_id).unwrap();
                     window_request.refresh_frame = true;
                 }
-                #[cfg(feature = "sctk-adwaita")]
-                WindowRequest::CsdThemeVariant(theme) => {
-                    window_handle.window.set_frame_config(theme.into());
-
-                    let window_requst = window_user_requests.get_mut(window_id).unwrap();
-                    window_requst.refresh_frame = true;
-                }
-                #[cfg(not(feature = "sctk-adwaita"))]
-                WindowRequest::CsdThemeVariant(_) => {}
                 WindowRequest::Resizeable(resizeable) => {
                     window_handle.window.set_resizable(resizeable);
 
@@ -537,6 +528,18 @@ pub fn handle_window_requests(winit_state: &mut WinitState) {
                     let event_sink = &mut winit_state.event_sink;
                     event_sink.push_window_event(WindowEvent::Destroyed, *window_id);
                 }
+                WindowRequest::Theme(_theme) => {
+                    #[cfg(feature = "sctk-adwaita")]
+                    {
+                        window_handle.window.set_frame_config(match _theme {
+                            Some(theme) => theme.into(),
+                            None => sctk_adwaita::FrameConfig::auto(),
+                        });
+
+                        let window_requst = window_user_requests.get_mut(window_id).unwrap();
+                        window_requst.refresh_frame = true;
+                    }
+                }
             };
         }
     }

src/platform_impl/linux/x11/window.rs

@@ -301,6 +301,10 @@ impl UnownedWindow {
             .set_decorations_inner(window_attrs.decorations)
             .queue();
 
+        if let Some(theme) = window_attrs.preferred_theme {
+            window.set_theme_inner(Some(theme)).queue();
+        }
+
         {
             // Enable drag and drop (TODO: extend API to make this toggleable)
             unsafe {
@@ -359,10 +363,6 @@ impl UnownedWindow {
 
             window.set_window_types(pl_attribs.x11_window_types).queue();
 
-            if let Some(variant) = pl_attribs.gtk_theme_variant {
-                window.set_gtk_theme_variant(variant).queue();
-            }
-
             // set size hints
             {
                 let mut min_inner_size = window_attrs
@@ -565,9 +565,14 @@ impl UnownedWindow {
         )
     }
 
-    fn set_gtk_theme_variant(&self, variant: String) -> util::Flusher<'_> {
+    pub fn set_theme_inner(&self, theme: Option<Theme>) -> util::Flusher<'_> {
         let hint_atom = unsafe { self.xconn.get_atom_unchecked(b"_GTK_THEME_VARIANT\0") };
         let utf8_atom = unsafe { self.xconn.get_atom_unchecked(b"UTF8_STRING\0") };
+        let variant = match theme {
+            Some(Theme::Dark) => "dark",
+            Some(Theme::Light) => "light",
+            None => "dark",
+        };
         let variant = CString::new(variant).expect("`_GTK_THEME_VARIANT` contained null byte");
         self.xconn.change_property(
             self.xwindow,
@@ -578,6 +583,13 @@ impl UnownedWindow {
         )
     }
 
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        self.set_theme_inner(theme)
+            .flush()
+            .expect("Failed to change window theme")
+    }
+
     fn set_netwm(
         &self,
         operation: util::StateOperation,

src/platform_impl/macos/appkit/application.rs

@@ -87,7 +87,7 @@ extern_methods!(
         }
 
         #[sel(setAppearance:)]
-        pub fn setAppearance(&self, appearance: &NSAppearance);
+        pub fn setAppearance(&self, appearance: Option<&NSAppearance>);
 
         #[sel(run)]
         pub unsafe fn run(&self);

src/platform_impl/macos/window.rs

@@ -399,7 +399,7 @@ impl WinitWindow {
 
         match attrs.preferred_theme {
             Some(theme) => {
-                set_ns_theme(theme);
+                set_ns_theme(Some(theme));
                 let mut state = this.shared_state.lock().unwrap();
                 state.current_theme = Some(theme);
             }
@@ -1125,6 +1125,12 @@ impl WinitWindow {
         state.current_theme
     }
 
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        set_ns_theme(theme);
+        self.lock_shared_state("set_theme").current_theme = theme.or_else(|| Some(get_ns_theme()));
+    }
+
     #[inline]
     pub fn set_content_protected(&self, protected: bool) {
         self.setSharingType(if protected {
@@ -1254,15 +1260,17 @@ pub(super) fn get_ns_theme() -> Theme {
     }
 }
 
-fn set_ns_theme(theme: Theme) {
+fn set_ns_theme(theme: Option<Theme>) {
     let app = NSApp();
     let has_theme: bool = unsafe { msg_send![&app, respondsToSelector: sel!(effectiveAppearance)] };
     if has_theme {
-        let name = match theme {
+        let appearance = theme.map(|t| {
+            let name = match t {
                 Theme::Dark => NSString::from_str("NSAppearanceNameDarkAqua"),
                 Theme::Light => NSString::from_str("NSAppearanceNameAqua"),
             };
-        let appearance = NSAppearance::appearanceNamed(&name);
-        app.setAppearance(&appearance);
+            NSAppearance::appearanceNamed(&name)
+        });
+        app.setAppearance(appearance.as_ref().map(|a| a.as_ref()));
     }
 }

src/platform_impl/web/window.rs

@@ -375,6 +375,9 @@ impl Window {
         RawDisplayHandle::Web(WebDisplayHandle::empty())
     }
 
+    #[inline]
+    pub fn set_theme(&self, _theme: Option<Theme>) {}
+
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         None

src/platform_impl/windows/window.rs

@@ -701,6 +701,11 @@ impl Window {
         });
     }
 
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        try_theme(self.window.0, theme);
+    }
+
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         Some(self.window_state_lock().current_theme)

src/window.rs

@@ -349,8 +349,10 @@ impl WindowBuilder {
     ///
     /// ## Platform-specific
     ///
+    /// - **macOS:** This is an app-wide setting.
     /// - **Wayland:** This control only CSD. You can also use `WINIT_WAYLAND_CSD_THEME` env variable to set the theme.
     ///   Possible values for env variable are: "dark" and light".
+    /// - **x11:** Build window with `_GTK_THEME_VARIANT` hint set to `dark` or `light`.
     /// - **iOS / Android / Web / x11:** Ignored.
     #[inline]
     pub fn with_theme(mut self, theme: Option<Theme>) -> Self {
@@ -963,11 +965,26 @@ impl Window {
         self.window.request_user_attention(request_type)
     }
 
+    /// Sets the current window theme. Use `None` to fallback to system default.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **macOS:** This is an app-wide setting.
+    /// - **Wayland:** You can also use `WINIT_WAYLAND_CSD_THEME` env variable to set the theme.
+    /// Possible values for env variable are: "dark" and light". When unspecified, a theme is automatically selected.
+    /// -**x11:** Sets `_GTK_THEME_VARIANT` hint to `dark` or `light` and if `None` is used, it will default to  [`Theme::Dark`].
+    /// - **iOS / Android / Web / x11:** Unsupported.
+    #[inline]
+    pub fn set_theme(&self, theme: Option<Theme>) {
+        self.window.set_theme(theme)
+    }
+
     /// Returns the current window theme.
     ///
     /// ## Platform-specific
     ///
-    /// - **iOS / Android / Web / x11:** Unsupported.
+    /// - **macOS:** This is an app-wide setting.
+    /// - **iOS / Android / Web / Wayland / x11:** Unsupported.
     #[inline]
     pub fn theme(&self) -> Option<Theme> {
         self.window.theme()