Fix scale_factor_override in the winit backend (#2784)

# Objective

- Fixes #2751

## Solution

- Avoid changing the window size if there is a scale factor override
- Can be tested with the `scale_factor_override` example - use <kbd>⏎</kbd> to active overriding the scale factor

Author: DJMcNab

crates/bevy_window/src/event.rs

@@ -3,11 +3,13 @@ use std::path::PathBuf;
 use super::{WindowDescriptor, WindowId};
 use bevy_math::{IVec2, Vec2};
 
-/// A window event that is sent whenever a window has been resized.
+/// A window event that is sent whenever a windows logical size has changed
 #[derive(Debug, Clone)]
 pub struct WindowResized {
     pub id: WindowId,
+    /// The new logical width of the window
     pub width: f32,
+    /// The new logical height of the window
     pub height: f32,
 }
 

crates/bevy_winit/Cargo.toml

@@ -23,6 +23,7 @@ bevy_utils = { path = "../bevy_utils", version = "0.5.0" }
 
 # other
 winit = { version = "0.25.0", default-features = false }
+approx = { version = "0.5.0", default-features = false }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 winit = { version = "0.25.0", features = ["web-sys"], default-features = false }

crates/bevy_winit/src/lib.rs

@@ -395,8 +395,20 @@ pub fn winit_runner_with(mut app: App, mut event_loop: EventLoop<()>) {
                             id: window_id,
                             scale_factor,
                         });
-                        #[allow(clippy::float_cmp)]
-                        if window.scale_factor() != scale_factor {
+                        let prior_factor = window.scale_factor();
+                        window.update_scale_factor_from_backend(scale_factor);
+                        let new_factor = window.scale_factor();
+                        if let Some(forced_factor) = window.scale_factor_override() {
+                            // If there is a scale factor override, then force that to be used
+                            // Otherwise, use the OS suggested size
+                            // We have already told the OS about our resize constraints, so
+                            // the new_inner_size should take those into account
+                            *new_inner_size = winit::dpi::LogicalSize::new(
+                                window.requested_width(),
+                                window.requested_height(),
+                            )
+                            .to_physical::<u32>(forced_factor);
+                        } else if approx::relative_ne!(new_factor, prior_factor) {
                             let mut scale_factor_change_events = world
                                 .get_resource_mut::<Events<WindowScaleFactorChanged>>()
                                 .unwrap();
@@ -407,17 +419,17 @@ pub fn winit_runner_with(mut app: App, mut event_loop: EventLoop<()>) {
                             });
                         }
 
-                        window.update_scale_factor_from_backend(scale_factor);
-
-                        if window.physical_width() != new_inner_size.width
-                            || window.physical_height() != new_inner_size.height
+                        let new_logical_width = new_inner_size.width as f64 / new_factor;
+                        let new_logical_height = new_inner_size.height as f64 / new_factor;
+                        if approx::relative_ne!(window.width() as f64, new_logical_width)
+                            || approx::relative_ne!(window.height() as f64, new_logical_height)
                         {
                             let mut resize_events =
                                 world.get_resource_mut::<Events<WindowResized>>().unwrap();
                             resize_events.send(WindowResized {
                                 id: window_id,
-                                width: window.width(),
-                                height: window.height(),
+                                width: new_logical_width as f32,
+                                height: new_logical_height as f32,
                             });
                         }
                         window.update_actual_size_from_backend(