wayland: use ext-background-effect if available

A more modern protocol compared to the KDE one.

(cherry picked from commit c4afadb)

Author: kchibisov

src/changelog/unreleased.md

@@ -16,6 +16,7 @@ on how to add them:
 - On X11, add `Window::even_more_rare_api`.
 - On Wayland, add `Window::common_api`.
 - On Windows, add `Window::some_rare_api`.
+- On Wayland, added ext-background-effect-v1 support.
 ```
 
 When the change requires non-trivial amount of work for users to comply

src/platform_impl/linux/wayland/state.rs

@@ -29,7 +29,7 @@ use crate::platform_impl::wayland::seat::{
     PointerConstraintsState, RelativePointerState, TextInputState, WinitPointerData,
     WinitPointerDataExt, WinitSeatState,
 };
-use crate::platform_impl::wayland::types::kwin_blur::KWinBlurManager;
+use crate::platform_impl::wayland::types::bgr_effects::BgrEffectManager;
 use crate::platform_impl::wayland::types::wp_fractional_scaling::FractionalScalingManager;
 use crate::platform_impl::wayland::types::wp_viewporter::ViewporterState;
 use crate::platform_impl::wayland::types::xdg_activation::XdgActivationState;
@@ -106,8 +106,8 @@ pub struct WinitState {
     /// Fractional scaling manager.
     pub fractional_scaling_manager: Option<FractionalScalingManager>,
 
-    /// KWin blur manager.
-    pub kwin_blur_manager: Option<KWinBlurManager>,
+    /// Blur manager.
+    pub blur_manager: Option<BgrEffectManager>,
 
     /// Loop handle to re-register event sources, such as keyboard repeat.
     pub loop_handle: LoopHandle<'static, Self>,
@@ -176,7 +176,7 @@ impl WinitState {
             window_events_sink: Default::default(),
             viewporter_state,
             fractional_scaling_manager,
-            kwin_blur_manager: KWinBlurManager::new(globals, queue_handle).ok(),
+            blur_manager: BgrEffectManager::new(globals, queue_handle).ok(),
 
             seats,
             text_input_state: TextInputState::new(globals, queue_handle).ok(),

src/platform_impl/linux/wayland/types/bgr_effects.rs

@@ -0,0 +1,85 @@
+use sctk::compositor::Region;
+use sctk::reexports::client::QueueHandle;
+use sctk::reexports::client::globals::{BindError, GlobalList};
+use sctk::reexports::client::protocol::wl_surface::WlSurface;
+use sctk::reexports::protocols::ext::background_effect::v1::client::ext_background_effect_surface_v1::ExtBackgroundEffectSurfaceV1;
+use wayland_protocols_plasma::blur::client::org_kde_kwin_blur::OrgKdeKwinBlur;
+
+use crate::platform_impl::wayland::state::WinitState;
+use crate::platform_impl::wayland::types::ext_background_effect::ExtBackgroundEffectManager;
+use crate::platform_impl::wayland::types::kwin_blur::KWinBlurManager;
+
+/// Wrapper around various background effects for [`WlSurface`].
+#[derive(Debug, Clone)]
+pub enum BgrEffectManager {
+    Ext(ExtBackgroundEffectManager),
+    KWin(KWinBlurManager),
+}
+
+impl BgrEffectManager {
+    pub fn new(
+        globals: &GlobalList,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> Result<Self, BindError> {
+        ExtBackgroundEffectManager::new(globals, queue_handle)
+        .map(Self::Ext)
+        .or_else(|_| KWinBlurManager::new(globals, queue_handle).map(Self::KWin))
+    }
+
+    /// Creates a new blur effect for the surface.
+    pub fn new_blur_effect(
+        &mut self,
+        surface: &WlSurface,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> SurfaceBlurEffect {
+        match self {
+            BgrEffectManager::Ext(mgr) => SurfaceBlurEffect::Ext(mgr.blur(surface, queue_handle)),
+            BgrEffectManager::KWin(mgr) => SurfaceBlurEffect::Kwin(
+                mgr.blur(surface, queue_handle),
+                                                                   mgr.clone(),
+                                                                   surface.clone(),
+            ),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum SurfaceBlurEffect {
+    Ext(ExtBackgroundEffectSurfaceV1),
+    Kwin(OrgKdeKwinBlur, KWinBlurManager, WlSurface),
+}
+
+impl SurfaceBlurEffect {
+    /// Returns `true` if the main surface commit is required.
+    ///
+    /// `None` clears the blur.
+    #[must_use]
+    pub fn set_blur(&self, region: Option<&Region>) -> bool {
+        let region = region.map(|region| region.wl_region());
+        match self {
+            SurfaceBlurEffect::Ext(surface) => {
+                surface.set_blur_region(region);
+                true
+            },
+            SurfaceBlurEffect::Kwin(blur, ..) => {
+                blur.set_region(region);
+                blur.commit();
+                true
+            },
+        }
+    }
+}
+
+impl Drop for SurfaceBlurEffect {
+    fn drop(&mut self) {
+        match self {
+            SurfaceBlurEffect::Ext(surface) => surface.destroy(),
+            SurfaceBlurEffect::Kwin(blur, mgr, wl_surface) => {
+                blur.set_region(None);
+                blur.commit();
+                blur.release();
+                mgr.unset(wl_surface);
+            },
+        }
+    }
+}

src/platform_impl/linux/wayland/types/ext_background_effect.rs

@@ -0,0 +1,59 @@
+use sctk::globals::GlobalData;
+use sctk::reexports::client::globals::{BindError, GlobalList};
+use sctk::reexports::client::protocol::wl_surface::WlSurface;
+use sctk::reexports::client::{Connection, Dispatch, Proxy, QueueHandle, delegate_dispatch};
+use wayland_protocols::ext::background_effect::v1::client::ext_background_effect_manager_v1::ExtBackgroundEffectManagerV1;
+use wayland_protocols::ext::background_effect::v1::client::ext_background_effect_surface_v1::ExtBackgroundEffectSurfaceV1;
+
+use crate::platform_impl::wayland::state::WinitState;
+
+#[derive(Debug, Clone)]
+pub struct ExtBackgroundEffectManager {
+    manager: ExtBackgroundEffectManagerV1,
+}
+
+impl ExtBackgroundEffectManager {
+    pub fn new(
+        globals: &GlobalList,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> Result<Self, BindError> {
+        let manager = globals.bind(queue_handle, 1..=1, GlobalData)?;
+        Ok(Self { manager })
+    }
+
+    pub fn blur(
+        &mut self,
+        surface: &WlSurface,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> ExtBackgroundEffectSurfaceV1 {
+        self.manager.get_background_effect(surface, queue_handle, ())
+    }
+}
+
+impl Dispatch<ExtBackgroundEffectManagerV1, GlobalData, WinitState> for ExtBackgroundEffectManager {
+    fn event(
+        _: &mut WinitState,
+        _: &ExtBackgroundEffectManagerV1,
+        _: <ExtBackgroundEffectManagerV1 as Proxy>::Event,
+        _: &GlobalData,
+        _: &Connection,
+        _: &QueueHandle<WinitState>,
+    ) {
+    }
+}
+
+impl Dispatch<ExtBackgroundEffectSurfaceV1, (), WinitState> for ExtBackgroundEffectManager {
+    fn event(
+        _: &mut WinitState,
+        _: &ExtBackgroundEffectSurfaceV1,
+        _: <ExtBackgroundEffectSurfaceV1 as Proxy>::Event,
+        _: &(),
+             _: &Connection,
+             _: &QueueHandle<WinitState>,
+    ) {
+        // There is no event
+    }
+}
+
+delegate_dispatch!(WinitState: [ExtBackgroundEffectManagerV1: GlobalData] => ExtBackgroundEffectManager);
+delegate_dispatch!(WinitState: [ExtBackgroundEffectSurfaceV1: ()] => ExtBackgroundEffectManager);

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

@@ -1,6 +1,8 @@
 //! Wayland protocol implementation boilerplate.
 
+pub mod bgr_effects;
 pub mod cursor;
+pub mod ext_background_effect;
 pub mod kwin_blur;
 pub mod wp_fractional_scaling;
 pub mod wp_viewporter;

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

@@ -119,7 +119,8 @@ impl Window {
         // Set transparency hint.
         window_state.set_transparent(attributes.transparent);
 
-        window_state.set_blur(attributes.blur);
+        // Set blur.
+        let _ = window_state.set_blur(attributes.blur);
 
         // Set the decorations hint.
         window_state.set_decorate(attributes.decorations);
@@ -413,7 +414,9 @@ impl Window {
 
     #[inline]
     pub fn set_blur(&self, blur: bool) {
-        self.window_state.lock().unwrap().set_blur(blur);
+        if self.window_state.lock().unwrap().set_blur(blur) {
+            self.request_redraw();
+        }
     }
 
     #[inline]

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

@@ -28,14 +28,13 @@ use sctk::shell::WaylandSurface;
 use sctk::shm::slot::SlotPool;
 use sctk::shm::Shm;
 use sctk::subcompositor::SubcompositorState;
-use wayland_protocols_plasma::blur::client::org_kde_kwin_blur::OrgKdeKwinBlur;
 
 use crate::cursor::CustomCursor as RootCustomCursor;
 use crate::dpi::{LogicalPosition, LogicalSize, PhysicalPosition, PhysicalSize, Size};
 use crate::error::{ExternalError, NotSupportedError};
 use crate::platform_impl::wayland::logical_to_physical_rounded;
 use crate::platform_impl::wayland::types::cursor::{CustomCursor, SelectedCursor};
-use crate::platform_impl::wayland::types::kwin_blur::KWinBlurManager;
+use crate::platform_impl::wayland::types::bgr_effects::{BgrEffectManager, SurfaceBlurEffect};
 use crate::platform_impl::{PlatformCustomCursor, WindowId};
 use crate::window::{CursorGrabMode, CursorIcon, ImePurpose, ResizeDirection, Theme};
 
@@ -143,8 +142,8 @@ pub struct WindowState {
 
     viewport: Option<WpViewport>,
     fractional_scale: Option<WpFractionalScaleV1>,
-    blur: Option<OrgKdeKwinBlur>,
-    blur_manager: Option<KWinBlurManager>,
+    blur: Option<SurfaceBlurEffect>,
+    blur_manager: Option<BgrEffectManager>,
 
     /// Whether the client side decorations have pending move operations.
     ///
@@ -185,7 +184,7 @@ impl WindowState {
 
         Self {
             blur: None,
-            blur_manager: winit_state.kwin_blur_manager.clone(),
+            blur_manager: winit_state.blur_manager.clone(),
             compositor,
             connection,
             csd_fails: false,
@@ -717,6 +716,13 @@ impl WindowState {
             // Set inner size without the borders.
             viewport.set_destination(self.size.width as _, self.size.height as _);
         }
+
+        // Update blur region with new size.
+        if self.blur.is_some() {
+            // NOTE: either user resized or configure, in both cases
+            // the redraw scheduling is done on the caller side.
+            let _ = self.set_blur(true);
+        }
     }
 
     /// Get the scale factor of the window.
@@ -1077,20 +1083,37 @@ impl WindowState {
         }
     }
 
-    /// Make window background blurred
-    #[inline]
-    pub fn set_blur(&mut self, blurred: bool) {
-        if blurred && self.blur.is_none() {
-            if let Some(blur_manager) = self.blur_manager.as_ref() {
-                let blur = blur_manager.blur(self.window.wl_surface(), &self.queue_handle);
-                blur.commit();
-                self.blur = Some(blur);
-            } else {
-                info!("Blur manager unavailable, unable to change blur")
-            }
-        } else if !blurred && self.blur.is_some() {
-            self.blur_manager.as_ref().unwrap().unset(self.window.wl_surface());
-            self.blur.take().unwrap().release();
+    /// Make window background blurred.
+    ///
+    /// Returns `true` if redraw is required.
+    #[must_use]
+    pub fn set_blur(&mut self, blurred: bool) -> bool {
+        if !blurred {
+            self.blur = None;
+            return true;
+        }
+
+        let mgr = match self.blur_manager.as_mut() {
+            Some(mgr) => mgr,
+            None => {
+                info!("Blur manager unavailable, unable to change blur");
+                return false;
+            },
+        };
+
+        let blur = match self.blur.as_ref() {
+            Some(blur) => blur,
+            None => {
+                self.blur = Some(mgr.new_blur_effect(self.window.wl_surface(), &self.queue_handle));
+                self.blur.as_ref().unwrap()
+            },
+        };
+
+        if let Ok(region) = Region::new(&*self.compositor) {
+            region.add(0, 0, i32::MAX, i32::MAX);
+            blur.set_blur(Some(&region))
+        } else {
+            false
         }
     }
 
@@ -1149,10 +1172,6 @@ impl WindowState {
 
 impl Drop for WindowState {
     fn drop(&mut self) {
-        if let Some(blur) = self.blur.take() {
-            blur.release();
-        }
-
         if let Some(fs) = self.fractional_scale.take() {
             fs.destroy();
         }

src/window.rs

@@ -954,7 +954,8 @@ impl Window {
     /// ## Platform-specific
     ///
     /// - **Android / iOS / X11 / Web / Windows:** Unsupported.
-    /// - **Wayland:** Only works with org_kde_kwin_blur_manager protocol.
+    /// - **Wayland:** Only works with `org_kde_kwin_blur_manager` or
+    ///   `ext_background_effect_manager_v1` protocol.
     #[inline]
     pub fn set_blur(&self, blur: bool) {
         let _span = tracing::debug_span!("winit::Window::set_blur", blur).entered();