Add Window::set_blur

Allow clients to request blur behind their window, implemented on
Wayland for now.

CHANGELOG.md

@@ -28,6 +28,7 @@ And please only add new entries to the top of this list, right below the `# Unre
 - **Breaking:** Change default `ControlFlow` from `Poll` to `Wait`.
 - **Breaking:** remove `DeviceEvent::Text`.
 - On Android, fix `DeviceId` to contain device id's.
+- Add `Window::set_blur` to request a blur behind the window; implemented on Wayland for now.
 
 # 0.29.1-beta
 

Cargo.toml

@@ -37,7 +37,7 @@ rustdoc-args = ["--cfg", "docsrs"]
 [features]
 default = ["x11", "wayland", "wayland-dlopen", "wayland-csd-adwaita"]
 x11 = ["x11-dl", "bytemuck", "percent-encoding", "xkbcommon-dl/x11", "x11rb"]
-wayland = ["wayland-client", "wayland-backend", "wayland-protocols", "sctk", "fnv", "memmap2"]
+wayland = ["wayland-client", "wayland-backend", "wayland-protocols", "wayland-protocols-plasma", "sctk", "fnv", "memmap2"]
 wayland-dlopen = ["wayland-backend/dlopen"]
 wayland-csd-adwaita = ["sctk-adwaita", "sctk-adwaita/ab_glyph"]
 wayland-csd-adwaita-crossfont = ["sctk-adwaita", "sctk-adwaita/crossfont"]
@@ -149,6 +149,7 @@ sctk-adwaita = { version = "0.6.0", default_features = false, optional = true }
 wayland-client = { version = "0.30.0", optional = true }
 wayland-backend = { version = "0.1.0", default_features = false, features = ["client_system"], optional = true }
 wayland-protocols = { version = "0.30.0", features = [ "staging"], optional = true }
+wayland-protocols-plasma = { version = "0.1.0", features = [ "client" ], optional = true }
 calloop = "0.10.5"
 rustix = { version = "0.38.4", default-features = false, features = ["std", "system", "thread", "process"] }
 x11-dl = { version = "2.18.5", optional = true }

FEATURES.md

@@ -182,6 +182,7 @@ Legend:
 |Window resizing                  |✔️     |✔️     |✔️         |✔️        |**N/A**|**N/A**|✔️        |✔️      |
 |Window resize increments         |❌     |✔️     |✔️         |❌             |**N/A**|**N/A**|**N/A**|**N/A** |
 |Window transparency              |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|N/A        |✔️      |
+|Window blur                      |❌    |❌    |❌        |✔️             |**N/A**|**N/A**|N/A        |❌     |
 |Window maximization              |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**|**N/A** |
 |Window maximization toggle       |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**|**N/A** |
 |Window minimization              |✔️     |✔️     |✔️         |✔️             |**N/A**|**N/A**|**N/A**|**N/A** |

src/platform_impl/android/mod.rs

@@ -843,6 +843,8 @@ impl Window {
 
     pub fn set_transparent(&self, _transparent: bool) {}
 
+    pub fn set_blur(&self, _blur: bool) {}
+
     pub fn set_visible(&self, _visibility: bool) {}
 
     pub fn is_visible(&self) -> Option<bool> {

src/platform_impl/ios/window.rs

@@ -42,6 +42,10 @@ impl Inner {
         debug!("`Window::set_transparent` is ignored on iOS")
     }
 
+    pub fn set_blur(&self, _blur: bool) {
+        debug!("`Window::set_blur` is ignored on iOS")
+    }
+
     pub fn set_visible(&self, visible: bool) {
         self.window.setHidden(!visible)
     }

src/platform_impl/linux/mod.rs

@@ -329,6 +329,11 @@ impl Window {
         x11_or_wayland!(match self; Window(w) => w.set_transparent(transparent));
     }
 
+    #[inline]
+    pub fn set_blur(&self, blur: bool) {
+        x11_or_wayland!(match self; Window(w) => w.set_blur(blur));
+    }
+
     #[inline]
     pub fn set_visible(&self, visible: bool) {
         x11_or_wayland!(match self; Window(w) => w.set_visible(visible))

src/platform_impl/linux/wayland/state.rs

@@ -31,6 +31,7 @@ use super::seat::{
     PointerConstraintsState, RelativePointerState, TextInputState, WinitPointerData,
     WinitPointerDataExt, WinitSeatState,
 };
+use super::types::kwin_blur::KWinBlurManager;
 use super::types::wp_fractional_scaling::FractionalScalingManager;
 use super::types::wp_viewporter::ViewporterState;
 use super::types::xdg_activation::XdgActivationState;
@@ -103,6 +104,9 @@ pub struct WinitState {
     /// Fractional scaling manager.
     pub fractional_scaling_manager: Option<FractionalScalingManager>,
 
+    /// KWin blur manager.
+    pub kwin_blur_manager: Option<KWinBlurManager>,
+
     /// Loop handle to re-register event sources, such as keyboard repeat.
     pub loop_handle: LoopHandle<'static, Self>,
 
@@ -161,6 +165,7 @@ impl WinitState {
             window_events_sink: Default::default(),
             viewporter_state,
             fractional_scaling_manager,
+            kwin_blur_manager: KWinBlurManager::new(globals, queue_handle).ok(),
 
             seats,
             text_input_state: TextInputState::new(globals, queue_handle).ok(),

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

@@ -0,0 +1,70 @@
+//! Handling of KDE-compatible blur.
+
+use sctk::reexports::client::globals::{BindError, GlobalList};
+use sctk::reexports::client::protocol::wl_surface::WlSurface;
+use sctk::reexports::client::Dispatch;
+use sctk::reexports::client::{delegate_dispatch, Connection, Proxy, QueueHandle};
+use wayland_protocols_plasma::blur::client::{
+    org_kde_kwin_blur::OrgKdeKwinBlur, org_kde_kwin_blur_manager::OrgKdeKwinBlurManager,
+};
+
+use sctk::globals::GlobalData;
+
+use crate::platform_impl::wayland::state::WinitState;
+
+/// KWin blur manager.
+#[derive(Debug, Clone)]
+pub struct KWinBlurManager {
+    manager: OrgKdeKwinBlurManager,
+}
+
+impl KWinBlurManager {
+    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(
+        &self,
+        surface: &WlSurface,
+        queue_handle: &QueueHandle<WinitState>,
+    ) -> OrgKdeKwinBlur {
+        self.manager.create(surface, queue_handle, ())
+    }
+
+    pub fn unset(&self, surface: &WlSurface) {
+        self.manager.unset(surface)
+    }
+}
+
+impl Dispatch<OrgKdeKwinBlurManager, GlobalData, WinitState> for KWinBlurManager {
+    fn event(
+        _: &mut WinitState,
+        _: &OrgKdeKwinBlurManager,
+        _: <OrgKdeKwinBlurManager as Proxy>::Event,
+        _: &GlobalData,
+        _: &Connection,
+        _: &QueueHandle<WinitState>,
+    ) {
+        unreachable!("no events defined for org_kde_kwin_blur_manager");
+    }
+}
+
+impl Dispatch<OrgKdeKwinBlur, (), WinitState> for KWinBlurManager {
+    fn event(
+        _: &mut WinitState,
+        _: &OrgKdeKwinBlur,
+        _: <OrgKdeKwinBlur as Proxy>::Event,
+        _: &(),
+        _: &Connection,
+        _: &QueueHandle<WinitState>,
+    ) {
+        unreachable!("no events defined for org_kde_kwin_blur");
+    }
+}
+
+delegate_dispatch!(WinitState: [OrgKdeKwinBlurManager: GlobalData] => KWinBlurManager);
+delegate_dispatch!(WinitState: [OrgKdeKwinBlur: ()] => KWinBlurManager);

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

@@ -1,5 +1,6 @@
 //! Wayland protocol implementation boilerplate.
 
+pub mod kwin_blur;
 pub mod wp_fractional_scaling;
 pub mod wp_viewporter;
 pub mod xdg_activation;

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

@@ -131,6 +131,8 @@ impl Window {
         // Set transparency hint.
         window_state.set_transparent(attributes.transparent);
 
+        window_state.set_blur(attributes.blur);
+
         // Set the decorations hint.
         window_state.set_decorate(attributes.decorations);
 
@@ -409,6 +411,11 @@ impl Window {
         self.window_state.lock().unwrap().scale_factor()
     }
 
+    #[inline]
+    pub fn set_blur(&self, blur: bool) {
+        self.window_state.lock().unwrap().set_blur(blur);
+    }
+
     #[inline]
     pub fn set_decorations(&self, decorate: bool) {
         self.window_state.lock().unwrap().set_decorate(decorate)

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

@@ -4,7 +4,7 @@ use std::mem::ManuallyDrop;
 use std::num::NonZeroU32;
 use std::sync::{Arc, Weak};
 
-use log::warn;
+use log::{info, warn};
 
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
 use sctk::reexports::client::protocol::wl_shm::WlShm;
@@ -23,9 +23,11 @@ use sctk::shell::xdg::XdgSurface;
 use sctk::shell::WaylandSurface;
 use sctk::shm::Shm;
 use sctk::subcompositor::SubcompositorState;
+use wayland_protocols_plasma::blur::client::org_kde_kwin_blur::OrgKdeKwinBlur;
 
 use crate::dpi::{LogicalPosition, LogicalSize};
 use crate::error::{ExternalError, NotSupportedError};
+use crate::platform_impl::wayland::types::kwin_blur::KWinBlurManager;
 use crate::platform_impl::WindowId;
 use crate::window::{CursorGrabMode, CursorIcon, ImePurpose, ResizeDirection, Theme};
 
@@ -130,6 +132,8 @@ pub struct WindowState {
 
     viewport: Option<WpViewport>,
     fractional_scale: Option<WpFractionalScaleV1>,
+    blur: Option<OrgKdeKwinBlur>,
+    blur_manager: Option<KWinBlurManager>,
 
     /// Whether the client side decorations have pending move operations.
     ///
@@ -159,6 +163,8 @@ impl WindowState {
             .map(|fsm| fsm.fractional_scaling(window.wl_surface(), queue_handle));
 
         Self {
+            blur: None,
+            blur_manager: winit_state.kwin_blur_manager.clone(),
             compositor,
             connection,
             csd_fails: false,
@@ -840,6 +846,26 @@ 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();
+        }
+    }
+
     /// Set the window title to a new value.
     ///
     /// This will autmatically truncate the title to something meaningfull.
@@ -900,6 +926,10 @@ impl Drop for WindowState {
             ManuallyDrop::drop(&mut self.window);
         }
 
+        if let Some(blur) = &self.blur {
+            blur.release();
+        }
+
         surface.destroy();
     }
 }

src/platform_impl/linux/x11/window.rs

@@ -1027,6 +1027,9 @@ impl UnownedWindow {
     #[inline]
     pub fn set_transparent(&self, _transparent: bool) {}
 
+    #[inline]
+    pub fn set_blur(&self, _blur: bool) {}
+
     fn set_decorations_inner(&self, decorations: bool) -> Result<VoidCookie<'_>, X11Error> {
         self.shared_state_lock().is_decorated = decorations;
         let mut hints = self.xconn.get_motif_hints(self.xwindow);

src/platform_impl/macos/window.rs

@@ -596,6 +596,8 @@ impl WinitWindow {
         self.setOpaque(!transparent)
     }
 
+    pub fn set_blur(&self, _blur: bool) {}
+
     pub fn set_visible(&self, visible: bool) {
         match visible {
             true => self.makeKeyAndOrderFront(None),

src/platform_impl/orbital/window.rs

@@ -261,6 +261,9 @@ impl Window {
     #[inline]
     pub fn set_transparent(&self, _transparent: bool) {}
 
+    #[inline]
+    pub fn set_blur(&self, _blur: bool) {}
+
     #[inline]
     pub fn set_visible(&self, _visibility: bool) {}
 

src/platform_impl/web/window.rs

@@ -92,6 +92,8 @@ impl Inner {
 
     pub fn set_transparent(&self, _transparent: bool) {}
 
+    pub fn set_blur(&self, _blur: bool) {}
+
     pub fn set_visible(&self, _visible: bool) {
         // Intentionally a no-op
     }

src/platform_impl/windows/window.rs

@@ -127,6 +127,8 @@ impl Window {
 
     pub fn set_transparent(&self, _transparent: bool) {}
 
+    pub fn set_blur(&self, _blur: bool) {}
+
     #[inline]
     pub fn set_visible(&self, visible: bool) {
         let window = self.window.clone();

src/window.rs

@@ -151,6 +151,7 @@ pub struct WindowAttributes {
     pub maximized: bool,
     pub visible: bool,
     pub transparent: bool,
+    pub blur: bool,
     pub decorations: bool,
     pub window_icon: Option<Icon>,
     pub preferred_theme: Option<Theme>,
@@ -176,6 +177,7 @@ impl Default for WindowAttributes {
             fullscreen: None,
             visible: true,
             transparent: false,
+            blur: false,
             decorations: true,
             window_level: Default::default(),
             window_icon: None,
@@ -343,6 +345,17 @@ impl WindowBuilder {
         self
     }
 
+    /// Sets whether the background of the window should be blurred by the system.
+    ///
+    /// The default is `false`.
+    ///
+    /// See [`Window::set_blur`] for details.
+    #[inline]
+    pub fn with_blur(mut self, blur: bool) -> Self {
+        self.window.blur = blur;
+        self
+    }
+
     /// Get whether the window will support transparency.
     #[inline]
     pub fn transparent(&self) -> bool {
@@ -884,6 +897,19 @@ impl Window {
             .maybe_queue_on_main(move |w| w.set_transparent(transparent))
     }
 
+    /// Change the window blur state.
+    ///
+    /// If `true`, this will make the transparent window background blurry.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **Android / iOS / macOS / X11 / Web / Windows:** Unsupported.
+    /// - **Wayland:** Only works with org_kde_kwin_blur_manager protocol.
+    #[inline]
+    pub fn set_blur(&self, blur: bool) {
+        self.window.maybe_queue_on_main(move |w| w.set_blur(blur))
+    }
+
     /// Modifies the window's visibility.
     ///
     /// If `false`, this will hide the window. If `true`, this will show the window.