refactor: better fractional scaling management

Cargo.lock

@@ -4012,9 +4012,9 @@ dependencies = [
 
 [[package]]
 name = "wayland-protocols-wlr"
-version = "0.3.3"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fd993de54a40a40fbe5601d9f1fbcaef0aebcc5fda447d7dc8f6dcbaae4f8953"
+checksum = "efd94963ed43cf9938a090ca4f7da58eb55325ec8200c3848963e98dc25b78ec"
 dependencies = [
  "bitflags 2.10.0",
  "wayland-backend",

Cargo.toml

@@ -38,4 +38,4 @@ slint-interpreter = { path = "../slint/internal/interpreter", default-features =
 smithay-client-toolkit = "0.20.0"
 thiserror = "2.0.17"
 wayland-client = "0.31.11"
-wayland-protocols = { version = "0.32.6", features = ["client", "staging"] }
+wayland-protocols = { version = "0.32.9", features = ["client", "staging"] }

src/windowing/mod.rs

@@ -24,6 +24,13 @@ use wayland_client::{
     },
     Connection, EventQueue, Proxy, QueueHandle,
 };
+use wayland_protocols::wp::fractional_scale::v1::client::{
+    wp_fractional_scale_manager_v1::WpFractionalScaleManagerV1,
+    wp_fractional_scale_v1::WpFractionalScaleV1,
+};
+use wayland_protocols::wp::viewporter::client::{
+    wp_viewport::WpViewport, wp_viewporter::WpViewporter,
+};
 
 pub mod builder;
 mod config;
@@ -44,14 +51,16 @@ impl WindowingSystem {
             Rc::new(Connection::connect_to_env().map_err(LayerShikaError::WaylandConnection)?);
         let event_queue = connection.new_event_queue();
 
-        let (compositor, output, layer_shell, seat) =
+        let (compositor, output, layer_shell, seat, fractional_scale_manager, viewporter) =
             Self::initialize_globals(&connection, &event_queue.handle())
                 .map_err(|e| LayerShikaError::GlobalInitialization(e.to_string()))?;
 
-        let (surface, layer_surface) = Self::setup_surface(
+        let (surface, layer_surface, fractional_scale, viewport) = Self::setup_surface(
             &compositor,
             &output,
             &layer_shell,
+            fractional_scale_manager.as_ref(),
+            viewporter.as_ref(),
             &event_queue.handle(),
             config,
         );
@@ -63,7 +72,7 @@ impl WindowingSystem {
             LayerShikaError::WindowConfiguration("Component definition is required".to_string())
         })?;
 
-        let state = WindowStateBuilder::new()
+        let mut builder = WindowStateBuilder::new()
             .with_component_definition(component_definition)
             .with_surface(Rc::clone(&surface))
             .with_layer_surface(Rc::clone(&layer_surface))
@@ -71,7 +80,17 @@ impl WindowingSystem {
             .with_scale_factor(config.scale_factor)
             .with_height(config.height)
             .with_exclusive_zone(config.exclusive_zone)
-            .with_window(window)
+            .with_window(window);
+
+        if let Some(fs) = fractional_scale {
+            builder = builder.with_fractional_scale(fs);
+        }
+
+        if let Some(vp) = viewport {
+            builder = builder.with_viewport(vp);
+        }
+
+        let state = builder
             .build()
             .map_err(|e| LayerShikaError::WindowConfiguration(e.to_string()))?;
 
@@ -89,7 +108,17 @@ impl WindowingSystem {
     fn initialize_globals(
         connection: &Connection,
         queue_handle: &QueueHandle<WindowState>,
-    ) -> Result<(WlCompositor, WlOutput, ZwlrLayerShellV1, WlSeat), LayerShikaError> {
+    ) -> Result<
+        (
+            WlCompositor,
+            WlOutput,
+            ZwlrLayerShellV1,
+            WlSeat,
+            Option<WpFractionalScaleManagerV1>,
+            Option<WpViewporter>,
+        ),
+        LayerShikaError,
+    > {
         let global_list = registry_queue_init::<WindowState>(connection)
             .map(|(global_list, _)| global_list)
             .map_err(|e| LayerShikaError::GlobalInitialization(e.to_string()))?;
@@ -97,22 +126,52 @@ impl WindowingSystem {
         let (compositor, output, layer_shell, seat) = bind_globals!(
             &global_list,
             queue_handle,
-            (WlCompositor, compositor, 1..=1),
-            (WlOutput, output, 1..=1),
-            (ZwlrLayerShellV1, layer_shell, 1..=1),
-            (WlSeat, seat, 1..=1)
+            (WlCompositor, compositor, 3..=6),
+            (WlOutput, output, 1..=4),
+            (ZwlrLayerShellV1, layer_shell, 1..=5),
+            (WlSeat, seat, 1..=9)
         )?;
 
-        Ok((compositor, output, layer_shell, seat))
+        let fractional_scale_manager = global_list
+            .bind::<WpFractionalScaleManagerV1, _, _>(queue_handle, 1..=1, ())
+            .ok();
+
+        let viewporter = global_list
+            .bind::<WpViewporter, _, _>(queue_handle, 1..=1, ())
+            .ok();
+
+        if fractional_scale_manager.is_none() {
+            info!("Fractional scale protocol not available, using integer scaling");
+        }
+
+        if viewporter.is_none() {
+            info!("Viewporter protocol not available");
+        }
+
+        Ok((
+            compositor,
+            output,
+            layer_shell,
+            seat,
+            fractional_scale_manager,
+            viewporter,
+        ))
     }
 
     fn setup_surface(
         compositor: &WlCompositor,
         output: &WlOutput,
         layer_shell: &ZwlrLayerShellV1,
+        fractional_scale_manager: Option<&WpFractionalScaleManagerV1>,
+        viewporter: Option<&WpViewporter>,
         queue_handle: &QueueHandle<WindowState>,
         config: &WindowConfig,
-    ) -> (Rc<WlSurface>, Rc<ZwlrLayerSurfaceV1>) {
+    ) -> (
+        Rc<WlSurface>,
+        Rc<ZwlrLayerSurfaceV1>,
+        Option<Rc<WpFractionalScaleV1>>,
+        Option<Rc<WpViewport>>,
+    ) {
         let surface = Rc::new(compositor.create_surface(queue_handle, ()));
         let layer_surface = Rc::new(layer_shell.get_layer_surface(
             &surface,
@@ -123,9 +182,21 @@ impl WindowingSystem {
             (),
         ));
 
+        let fractional_scale = fractional_scale_manager.map(|manager| {
+            info!("Creating fractional scale object for surface");
+            Rc::new(manager.get_fractional_scale(&surface, queue_handle, ()))
+        });
+
+        let viewport = viewporter.map(|vp| {
+            info!("Creating viewport for surface");
+            Rc::new(vp.get_viewport(&surface, queue_handle, ()))
+        });
+
         Self::configure_layer_surface(&layer_surface, &surface, config);
 
-        (surface, layer_surface)
+        surface.set_buffer_scale(1);
+
+        (surface, layer_surface, fractional_scale, viewport)
     }
 
     fn configure_layer_surface(

src/windowing/state/builder.rs

@@ -3,6 +3,8 @@ use slint::PhysicalSize;
 use slint_interpreter::ComponentDefinition;
 use smithay_client_toolkit::reexports::protocols_wlr::layer_shell::v1::client::zwlr_layer_surface_v1::ZwlrLayerSurfaceV1;
 use wayland_client::protocol::{wl_pointer::WlPointer, wl_surface::WlSurface};
+use wayland_protocols::wp::fractional_scale::v1::client::wp_fractional_scale_v1::WpFractionalScaleV1;
+use wayland_protocols::wp::viewporter::client::wp_viewport::WpViewport;
 use crate::{errors::LayerShikaError, rendering::{femtovg_window::FemtoVGWindow, slint_platform::CustomSlintPlatform}};
 
 use super::WindowState;
@@ -11,6 +13,8 @@ pub struct WindowStateBuilder {
     pub component_definition: Option<ComponentDefinition>,
     pub surface: Option<Rc<WlSurface>>,
     pub layer_surface: Option<Rc<ZwlrLayerSurfaceV1>>,
+    pub fractional_scale: Option<Rc<WpFractionalScaleV1>>,
+    pub viewport: Option<Rc<WpViewport>>,
     pub size: Option<PhysicalSize>,
     pub output_size: Option<PhysicalSize>,
     pub pointer: Option<Rc<WlPointer>>,
@@ -86,6 +90,18 @@ impl WindowStateBuilder {
         self
     }
 
+    #[must_use]
+    pub fn with_fractional_scale(mut self, fractional_scale: Rc<WpFractionalScaleV1>) -> Self {
+        self.fractional_scale = Some(fractional_scale);
+        self
+    }
+
+    #[must_use]
+    pub fn with_viewport(mut self, viewport: Rc<WpViewport>) -> Self {
+        self.viewport = Some(viewport);
+        self
+    }
+
     pub fn build(self) -> Result<WindowState, LayerShikaError> {
         let platform = CustomSlintPlatform::new(Rc::clone(
             self.window
@@ -106,6 +122,8 @@ impl Default for WindowStateBuilder {
             component_definition: None,
             surface: None,
             layer_surface: None,
+            fractional_scale: None,
+            viewport: None,
             size: None,
             output_size: None,
             pointer: None,

src/windowing/state/dispatches.rs

@@ -21,10 +21,20 @@ use wayland_client::{
     },
     Connection, Dispatch, Proxy, QueueHandle,
 };
+use wayland_protocols::wp::fractional_scale::v1::client::{
+    wp_fractional_scale_manager_v1::WpFractionalScaleManagerV1,
+    wp_fractional_scale_v1::{self, WpFractionalScaleV1},
+};
+use wayland_protocols::wp::viewporter::client::{
+    wp_viewport::WpViewport, wp_viewporter::WpViewporter,
+};
 
 use super::WindowState;
 
 impl Dispatch<ZwlrLayerSurfaceV1, ()> for WindowState {
+    #[allow(clippy::cast_possible_truncation)]
+    #[allow(clippy::cast_sign_loss)]
+    #[allow(clippy::cast_precision_loss)]
     fn event(
         state: &mut Self,
         layer_surface: &ZwlrLayerSurfaceV1,
@@ -39,14 +49,49 @@ impl Dispatch<ZwlrLayerSurfaceV1, ()> for WindowState {
                 width,
                 height,
             } => {
-                info!("Layer surface configured with size: {}x{}", width, height);
+                info!(
+                    "Layer surface configured with compositor size: {}x{}",
+                    width, height
+                );
                 layer_surface.ack_configure(serial);
-                if width > 0 && height > 0 {
-                    state.update_size(state.output_size().width, state.height());
+
+                let output_width = state.output_size().width;
+                let scale_factor = state.scale_factor();
+
+                let target_width = if width == 0 || (width == 1 && output_width > 1) {
+                    if scale_factor > 1.0 {
+                        (output_width as f32 / scale_factor).round() as u32
+                    } else {
+                        output_width
+                    }
                 } else {
-                    let current_size = state.output_size();
-                    state.update_size(current_size.width, current_size.height);
-                }
+                    width
+                };
+
+                let target_height = if height > 0 {
+                    height
+                } else {
+                    let h = state.height();
+                    if scale_factor > 1.0 {
+                        (h as f32 / scale_factor).round() as u32
+                    } else {
+                        h
+                    }
+                };
+
+                let clamped_width = target_width.min(output_width);
+
+                info!(
+                    "Using dimensions: {}x{} (clamped from {}x{}, output: {}x{})",
+                    clamped_width,
+                    target_height,
+                    target_width,
+                    target_height,
+                    output_width,
+                    state.output_size().height
+                );
+
+                state.update_size(clamped_width, target_height);
             }
             zwlr_layer_surface_v1::Event::Closed => {
                 info!("Layer surface closed");
@@ -153,10 +198,31 @@ impl Dispatch<WlPointer, ()> for WindowState {
     }
 }
 
+impl Dispatch<WpFractionalScaleV1, ()> for WindowState {
+    fn event(
+        state: &mut Self,
+        _proxy: &WpFractionalScaleV1,
+        event: wp_fractional_scale_v1::Event,
+        _data: &(),
+        _conn: &Connection,
+        _qhandle: &QueueHandle<Self>,
+    ) {
+        if let wp_fractional_scale_v1::Event::PreferredScale { scale } = event {
+            #[allow(clippy::cast_precision_loss)]
+            let scale_float = scale as f32 / 120.0;
+            info!("Fractional scale received: {scale_float} ({scale}x)");
+            state.update_scale_factor(scale);
+        }
+    }
+}
+
 impl_empty_dispatch!(
     (WlRegistry, GlobalListContents),
     (WlCompositor, ()),
     (WlSurface, ()),
     (ZwlrLayerShellV1, ()),
-    (WlSeat, ())
+    (WlSeat, ()),
+    (WpFractionalScaleManagerV1, ()),
+    (WpViewporter, ()),
+    (WpViewport, ())
 );

src/windowing/state/mod.rs

@@ -5,6 +5,8 @@ use slint::{LogicalPosition, PhysicalSize, ComponentHandle};
 use slint_interpreter::ComponentInstance;
 use smithay_client_toolkit::reexports::protocols_wlr::layer_shell::v1::client::zwlr_layer_surface_v1::ZwlrLayerSurfaceV1;
 use wayland_client::protocol::wl_surface::WlSurface;
+use wayland_protocols::wp::fractional_scale::v1::client::wp_fractional_scale_v1::WpFractionalScaleV1;
+use wayland_protocols::wp::viewporter::client::wp_viewport::WpViewport;
 use crate::rendering::femtovg_window::FemtoVGWindow;
 use crate::errors::LayerShikaError;
 
@@ -15,7 +17,10 @@ pub struct WindowState {
     component_instance: ComponentInstance,
     surface: Rc<WlSurface>,
     layer_surface: Rc<ZwlrLayerSurfaceV1>,
+    fractional_scale: Option<Rc<WpFractionalScaleV1>>,
+    viewport: Option<Rc<WpViewport>>,
     size: PhysicalSize,
+    logical_size: PhysicalSize,
     output_size: PhysicalSize,
     window: Rc<FemtoVGWindow>,
     current_pointer_position: LogicalPosition,
@@ -39,7 +44,6 @@ impl WindowState {
             .show()
             .map_err(|e| LayerShikaError::SlintComponentCreation(e.to_string()))?;
 
-        // Request initial redraw to ensure the first frame is rendered
         window.request_redraw();
 
         Ok(Self {
@@ -50,7 +54,10 @@ impl WindowState {
             layer_surface: builder
                 .layer_surface
                 .ok_or_else(|| LayerShikaError::InvalidInput("Layer surface is required".into()))?,
+            fractional_scale: builder.fractional_scale,
+            viewport: builder.viewport,
             size: builder.size.unwrap_or_default(),
+            logical_size: PhysicalSize::default(),
             output_size: builder.output_size.unwrap_or_default(),
             window,
             current_pointer_position: LogicalPosition::default(),
@@ -61,27 +68,92 @@ impl WindowState {
     }
 
     pub fn update_size(&mut self, width: u32, height: u32) {
-        let new_size = PhysicalSize::new(width, height);
-        info!("Updating window size to {}x{}", width, height);
-        self.window.set_size(slint::WindowSize::Physical(new_size));
-        self.window.set_scale_factor(self.scale_factor);
+        if width == 0 || height == 0 {
+            info!(
+                "Skipping update_size with zero dimension: {}x{}",
+                width, height
+            );
+            return;
+        }
+
+        #[allow(clippy::cast_possible_truncation)]
+        #[allow(clippy::cast_sign_loss)]
+        #[allow(clippy::cast_precision_loss)]
+        let physical_width = (width as f32 * self.scale_factor).round() as u32;
+        #[allow(clippy::cast_possible_truncation)]
+        #[allow(clippy::cast_sign_loss)]
+        #[allow(clippy::cast_precision_loss)]
+        let physical_height = (height as f32 * self.scale_factor).round() as u32;
+
+        let new_physical_size = PhysicalSize::new(physical_width, physical_height);
+        let new_logical_size = PhysicalSize::new(width, height);
+
+        info!(
+            "Updating window size: buffer {}x{}, physical {}x{}, scale {}, has_viewport: {}",
+            width,
+            height,
+            physical_width,
+            physical_height,
+            self.scale_factor,
+            self.viewport.is_some()
+        );
+
+        if self.fractional_scale.is_some() && self.viewport.is_some() {
+            self.surface.set_buffer_scale(1);
+            self.window
+                .set_size(slint::WindowSize::Logical(slint::LogicalSize::new(
+                    width as f32,
+                    height as f32,
+                )));
+            self.window.set_scale_factor(self.scale_factor);
+
+            if let Some(viewport) = &self.viewport {
+                viewport.set_destination(width as i32, height as i32);
+            }
+        } else if self.fractional_scale.is_some() {
+            #[allow(clippy::cast_possible_truncation)]
+            let buffer_scale = self.scale_factor.round() as i32;
+            self.surface.set_buffer_scale(buffer_scale);
+
+            self.window
+                .set_size(slint::WindowSize::Logical(slint::LogicalSize::new(
+                    width as f32,
+                    height as f32,
+                )));
+            #[allow(clippy::cast_precision_loss)]
+            self.window.set_scale_factor(buffer_scale as f32);
+        } else {
+            #[allow(clippy::cast_possible_truncation)]
+            let buffer_scale = self.scale_factor.round() as i32;
+            self.surface.set_buffer_scale(buffer_scale);
+
+            self.window
+                .set_size(slint::WindowSize::Physical(new_physical_size));
+            self.window.set_scale_factor(self.scale_factor);
+        }
+
+        info!("Window physical size: {:?}", self.window.size());
 
-        info!("Updating layer surface size to {}x{}", width, height);
         self.layer_surface.set_size(width, height);
         self.layer_surface.set_exclusive_zone(self.exclusive_zone);
-
         self.surface.commit();
-        self.size = new_size;
+
+        self.size = new_physical_size;
+        self.logical_size = new_logical_size;
         self.window.request_redraw();
     }
 
     #[allow(clippy::cast_possible_truncation)]
     pub fn set_current_pointer_position(&mut self, physical_x: f64, physical_y: f64) {
-        let scale_factor = self.scale_factor;
-        let logical_position = LogicalPosition::new(
-            physical_x as f32 / scale_factor,
-            physical_y as f32 / scale_factor,
-        );
+        let logical_position = if self.fractional_scale.is_some() {
+            LogicalPosition::new(physical_x as f32, physical_y as f32)
+        } else {
+            let scale_factor = self.scale_factor;
+            LogicalPosition::new(
+                physical_x as f32 / scale_factor,
+                physical_y as f32 / scale_factor,
+            )
+        };
         self.current_pointer_position = logical_position;
     }
 
@@ -120,4 +192,23 @@ impl WindowState {
     pub const fn component_instance(&self) -> &ComponentInstance {
         &self.component_instance
     }
+
+    pub fn update_scale_factor(&mut self, scale_120ths: u32) {
+        #[allow(clippy::cast_precision_loss)]
+        let new_scale_factor = scale_120ths as f32 / 120.0;
+        info!(
+            "Updating scale factor from {} to {} ({}x)",
+            self.scale_factor, new_scale_factor, scale_120ths
+        );
+        self.scale_factor = new_scale_factor;
+
+        let current_logical_size = self.logical_size;
+        if current_logical_size.width > 0 && current_logical_size.height > 0 {
+            self.update_size(current_logical_size.width, current_logical_size.height);
+        }
+    }
+
+    pub const fn scale_factor(&self) -> f32 {
+        self.scale_factor
+    }
 }