On Wayland, provide option for better CSD

While most compositors provide server side decorations, the GNOME
does not, and won't provide them. Also Wayland clients must render
client side decorations.

Winit was already drawing some decorations, however they were bad
looking and provided no text rendering, so the title was missing.
However this commit makes use of the SCTK external frame similar to
GTK's Adwaita theme supporting text rendering and looking similar to
other GTK applications.

Fixes #1967.

src/platform_impl/linux/mod.rs

@@ -9,8 +9,11 @@
 #[cfg(all(not(feature = "x11"), not(feature = "wayland")))]
 compile_error!("Please select a feature to build for unix: `x11`, `wayland`");
 
+#[cfg(feature = "wayland")]
+use crate::window::Theme;
 #[cfg(feature = "wayland")]
 use std::error::Error;
+
 use std::{collections::VecDeque, env, fmt};
 #[cfg(feature = "x11")]
 use std::{ffi::CStr, mem::MaybeUninit, os::raw::*, sync::Arc};
@@ -101,6 +104,8 @@ pub struct PlatformSpecificWindowBuilderAttributes {
     pub x11_window_types: Vec<XWindowType>,
     #[cfg(feature = "x11")]
     pub gtk_theme_variant: Option<String>,
+    #[cfg(feature = "wayland")]
+    pub csd_theme: Option<Theme>,
 }
 
 impl Default for PlatformSpecificWindowBuilderAttributes {
@@ -121,6 +126,8 @@ impl Default for PlatformSpecificWindowBuilderAttributes {
             x11_window_types: vec![XWindowType::Normal],
             #[cfg(feature = "x11")]
             gtk_theme_variant: None,
+            #[cfg(feature = "wayland")]
+            csd_theme: None,
         }
     }
 }

src/platform_impl/linux/wayland/seat/pointer/mod.rs

@@ -13,10 +13,11 @@ use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_p
 use sctk::reexports::protocols::unstable::pointer_constraints::v1::client::zwp_confined_pointer_v1::ZwpConfinedPointerV1;
 
 use sctk::seat::pointer::{ThemeManager, ThemedPointer};
-use sctk::window::{FallbackFrame, Window};
+use sctk::window::Window;
 
 use crate::event::ModifiersState;
 use crate::platform_impl::wayland::event_loop::WinitState;
+use crate::platform_impl::wayland::window::WinitFrame;
 use crate::window::CursorIcon;
 
 mod data;
@@ -156,7 +157,7 @@ impl WinitPointer {
         }
     }
 
-    pub fn drag_window(&self, window: &Window<FallbackFrame>) {
+    pub fn drag_window(&self, window: &Window<WinitFrame>) {
         // WlPointer::setart_interactive_move() expects the last serial of *any*
         // pointer event (compare to set_cursor()).
         window.start_interactive_move(&self.seat, self.latest_serial.get());

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

@@ -8,7 +8,7 @@ use sctk::reexports::client::Display;
 use sctk::reexports::calloop;
 
 use raw_window_handle::WaylandHandle;
-use sctk::window::{Decorations, FallbackFrame};
+use sctk::window::Decorations;
 
 use crate::dpi::{LogicalSize, PhysicalPosition, PhysicalSize, Position, Size};
 use crate::error::{ExternalError, NotSupportedError, OsError as RootOsError};
@@ -17,7 +17,7 @@ use crate::platform_impl::{
     MonitorHandle as PlatformMonitorHandle, OsError,
     PlatformSpecificWindowBuilderAttributes as PlatformAttributes,
 };
-use crate::window::{CursorIcon, Fullscreen, UserAttentionType, WindowAttributes};
+use crate::window::{CursorIcon, Fullscreen, Theme, UserAttentionType, WindowAttributes};
 
 use super::env::WindowingFeatures;
 use super::event_loop::WinitState;
@@ -28,6 +28,14 @@ pub mod shim;
 
 use shim::{WindowHandle, WindowRequest, WindowUpdate};
 
+#[cfg(feature = "sctk-adwaita")]
+pub type WinitFrame = sctk_adwaita::AdwaitaFrame;
+#[cfg(not(feature = "sctk-adwaita"))]
+pub type WinitFrame = sctk::window::FallbackFrame;
+
+#[cfg(feature = "sctk-adwaita")]
+const WAYLAND_CSD_THEME_ENV_VAR: &str = "WINIT_WAYLAND_CSD_THEME";
+
 pub struct Window {
     /// Window id.
     window_id: WindowId,
@@ -105,7 +113,7 @@ impl Window {
         let theme_manager = event_loop_window_target.theme_manager.clone();
         let mut window = event_loop_window_target
             .env
-            .create_window::<FallbackFrame, _>(
+            .create_window::<WinitFrame, _>(
                 surface.clone(),
                 Some(theme_manager),
                 (width, height),
@@ -139,6 +147,20 @@ impl Window {
             )
             .map_err(|_| os_error!(OsError::WaylandMisc("failed to create window.")))?;
 
+        // Set CSD frame config
+        #[cfg(feature = "sctk-adwaita")]
+        {
+            let theme = platform_attributes.csd_theme.unwrap_or_else(|| {
+                let env = std::env::var(WAYLAND_CSD_THEME_ENV_VAR).unwrap_or_default();
+                match env.to_lowercase().as_str() {
+                    "dark" => Theme::Dark,
+                    _ => Theme::Light,
+                }
+            });
+
+            window.set_frame_config(theme.into());
+        }
+
         // Set decorations.
         if attributes.decorations {
             window.set_decorate(Decorations::FollowServer);
@@ -380,6 +402,11 @@ 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.
@@ -550,3 +577,13 @@ impl Drop for Window {
         self.send_request(WindowRequest::Close);
     }
 }
+
+#[cfg(feature = "sctk-adwaita")]
+impl From<Theme> for sctk_adwaita::FrameConfig {
+    fn from(theme: Theme) -> Self {
+        match theme {
+            Theme::Light => sctk_adwaita::FrameConfig::light(),
+            Theme::Dark => sctk_adwaita::FrameConfig::dark(),
+        }
+    }
+}

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

@@ -8,7 +8,7 @@ use sctk::reexports::protocols::staging::xdg_activation::v1::client::xdg_activat
 use sctk::reexports::protocols::staging::xdg_activation::v1::client::xdg_activation_v1::XdgActivationV1;
 
 use sctk::environment::Environment;
-use sctk::window::{Decorations, FallbackFrame, Window};
+use sctk::window::{Decorations, Window};
 
 use crate::dpi::{LogicalPosition, LogicalSize};
 
@@ -19,7 +19,9 @@ use crate::platform_impl::wayland::event_loop::{EventSink, WinitState};
 use crate::platform_impl::wayland::seat::pointer::WinitPointer;
 use crate::platform_impl::wayland::seat::text_input::TextInputHandler;
 use crate::platform_impl::wayland::WindowId;
-use crate::window::{CursorIcon, UserAttentionType};
+use crate::window::{CursorIcon, Theme, UserAttentionType};
+
+use super::WinitFrame;
 
 /// A request to SCTK window from Winit window.
 #[derive(Debug, Clone)]
@@ -53,6 +55,9 @@ pub enum WindowRequest {
     /// Request decorations change.
     Decorate(bool),
 
+    /// Request decorations change.
+    CsdThemeVariant(Theme),
+
     /// Make the window resizeable.
     Resizeable(bool),
 
@@ -146,7 +151,7 @@ impl WindowUpdate {
 /// and react to events.
 pub struct WindowHandle {
     /// An actual window.
-    pub window: Window<FallbackFrame>,
+    pub window: Window<WinitFrame>,
 
     /// The current size of the window.
     pub size: Arc<Mutex<LogicalSize<u32>>>,
@@ -188,7 +193,7 @@ pub struct WindowHandle {
 impl WindowHandle {
     pub fn new(
         env: &Environment<WinitEnv>,
-        window: Window<FallbackFrame>,
+        window: Window<WinitFrame>,
         size: Arc<Mutex<LogicalSize<u32>>>,
         pending_window_requests: Arc<Mutex<Vec<WindowRequest>>>,
     ) -> Self {
@@ -450,6 +455,15 @@ pub fn handle_window_requests(winit_state: &mut WinitState) {
                     let window_update = window_updates.get_mut(window_id).unwrap();
                     window_update.refresh_frame = true;
                 }
+                #[cfg(feature = "sctk-adwaita")]
+                WindowRequest::CsdThemeVariant(theme) => {
+                    window_handle.window.set_frame_config(theme.into());
+
+                    let window_update = window_updates.get_mut(window_id).unwrap();
+                    window_update.refresh_frame = true;
+                }
+                #[cfg(not(feature = "sctk-adwaita"))]
+                WindowRequest::CsdThemeVariant(_) => {}
                 WindowRequest::Resizeable(resizeable) => {
                     window_handle.window.set_resizable(resizeable);