Fix incorrect window sizes for non-resizable windows on Wayland (#7103)

Using physical window sizes leads to all kinds of fun stuff: winit
always uses scale factor 1.0 on start to convert it back to logical
pixels and uses these logical pixels to set min/max size for
non-resizeable windows. You're supposed to adjust size after getting a
scale change event if you're using physical sizes, but adjusting min/max
sizes doesn't seem to work on sway, so the window is stuck with an
incorrect size.

The scale factor we guessed might also be wrong even if there's only a
single display since it doesn't take fractional scale into account.

TL;DR: winit actually wants logical sizes in these methods (since
Wayland in general operates mostly on logical sizes) and converting them
back and forth is lossy.

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* Closes https://github.com/emilk/egui/issues/7095
* [x] I have followed the instructions in the PR template

---------

Co-authored-by: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>

crates/eframe/src/native/glow_integration.rs

@@ -959,7 +959,6 @@ impl GlutinWindowContext {
             .with_preference(glutin_winit::ApiPreference::FallbackEgl)
             .with_window_attributes(Some(egui_winit::create_winit_window_attributes(
                 egui_ctx,
-                event_loop,
                 viewport_builder.clone(),
             )));
 
@@ -1113,7 +1112,6 @@ impl GlutinWindowContext {
             log::debug!("Creating a window for viewport {viewport_id:?}");
             let window_attributes = egui_winit::create_winit_window_attributes(
                 &self.egui_ctx,
-                event_loop,
                 viewport.builder.clone(),
             );
             if window_attributes.transparent()

crates/egui-winit/src/lib.rs

@@ -1566,8 +1566,7 @@ pub fn create_window(
 ) -> Result<Window, winit::error::OsError> {
     profiling::function_scope!();
 
-    let window_attributes =
+    let window_attributes = create_winit_window_attributes(egui_ctx, viewport_builder.clone());
-        create_winit_window_attributes(egui_ctx, event_loop, viewport_builder.clone());
     let window = event_loop.create_window(window_attributes)?;
     apply_viewport_builder_to_window(egui_ctx, &window, viewport_builder);
     Ok(window)
@@ -1575,28 +1574,10 @@ pub fn create_window(
 
 pub fn create_winit_window_attributes(
     egui_ctx: &egui::Context,
-    event_loop: &ActiveEventLoop,
     viewport_builder: ViewportBuilder,
 ) -> winit::window::WindowAttributes {
     profiling::function_scope!();
 
-    // We set sizes and positions in egui:s own ui points, which depends on the egui
-    // zoom_factor and the native pixels per point, so we need to know that here.
-    // We don't know what monitor the window will appear on though, but
-    // we'll try to fix that after the window is created in the call to `apply_viewport_builder_to_window`.
-    let native_pixels_per_point = event_loop
-        .primary_monitor()
-        .or_else(|| event_loop.available_monitors().next())
-        .map_or_else(
-            || {
-                log::debug!("Failed to find a monitor - assuming native_pixels_per_point of 1.0");
-                1.0
-            },
-            |m| m.scale_factor() as f32,
-        );
-    let zoom_factor = egui_ctx.zoom_factor();
-    let pixels_per_point = zoom_factor * native_pixels_per_point;
-
     let ViewportBuilder {
         title,
         position,
@@ -1672,40 +1653,46 @@ pub fn create_winit_window_attributes(
         })
         .with_active(active.unwrap_or(true));
 
+    // Here and below: we create `LogicalSize` / `LogicalPosition` taking
+    // zoom factor into account. We don't have a good way to get physical size here,
+    // and trying to do it anyway leads to weird bugs on Wayland, see:
+    // https://github.com/emilk/egui/issues/7095#issuecomment-2920545377
+    // https://github.com/rust-windowing/winit/issues/4266
+    #[expect(
+        clippy::disallowed_types,
+        reason = "zoom factor is manually accounted for"
+    )]
     #[cfg(not(target_os = "ios"))]
-    if let Some(size) = inner_size {
+    {
-        window_attributes = window_attributes.with_inner_size(PhysicalSize::new(
+        use winit::dpi::{LogicalPosition, LogicalSize};
-            pixels_per_point * size.x,
+        let zoom_factor = egui_ctx.zoom_factor();
-            pixels_per_point * size.y,
-        ));
-    }
 
-    #[cfg(not(target_os = "ios"))]
+        if let Some(size) = inner_size {
-    if let Some(size) = min_inner_size {
+            window_attributes = window_attributes
-        window_attributes = window_attributes.with_min_inner_size(PhysicalSize::new(
+                .with_inner_size(LogicalSize::new(zoom_factor * size.x, zoom_factor * size.y));
-            pixels_per_point * size.x,
+        }
-            pixels_per_point * size.y,
-        ));
-    }
 
-    #[cfg(not(target_os = "ios"))]
+        if let Some(size) = min_inner_size {
-    if let Some(size) = max_inner_size {
+            window_attributes = window_attributes
-        window_attributes = window_attributes.with_max_inner_size(PhysicalSize::new(
+                .with_min_inner_size(LogicalSize::new(zoom_factor * size.x, zoom_factor * size.y));
-            pixels_per_point * size.x,
+        }
-            pixels_per_point * size.y,
-        ));
-    }
 
-    #[cfg(not(target_os = "ios"))]
+        if let Some(size) = max_inner_size {
-    if let Some(pos) = position {
+            window_attributes = window_attributes
-        window_attributes = window_attributes.with_position(PhysicalPosition::new(
+                .with_max_inner_size(LogicalSize::new(zoom_factor * size.x, zoom_factor * size.y));
-            pixels_per_point * pos.x,
+        }
-            pixels_per_point * pos.y,
+
-        ));
+        if let Some(pos) = position {
+            window_attributes = window_attributes.with_position(LogicalPosition::new(
+                zoom_factor * pos.x,
+                zoom_factor * pos.y,
+            ));
+        }
     }
     #[cfg(target_os = "ios")]
     {
         // Unused:
+        _ = egui_ctx;
         _ = pixels_per_point;
         _ = position;
         _ = inner_size;