Added use_dpi setting to WindowDescriptor

Cargo.toml

@@ -346,6 +346,10 @@ path = "examples/window/clear_color.rs"
 name = "multiple_windows"
 path = "examples/window/multiple_windows.rs"
 
+[[example]]
+name = "scale_factor_override"
+path = "examples/window/scale_factor_override.rs"
+
 [[example]]
 name = "window_settings"
 path = "examples/window/window_settings.rs"

crates/bevy_ui/src/flex/mod.rs

@@ -1,12 +1,13 @@
 mod convert;
 
 use crate::{Node, Style};
-use bevy_ecs::{Changed, Entity, Query, Res, ResMut, With, Without};
+use bevy_app::{EventReader, Events};
+use bevy_ecs::{Changed, Entity, Local, Query, QueryFilter, Res, ResMut, With, Without};
 use bevy_math::Vec2;
 use bevy_text::CalculatedSize;
 use bevy_transform::prelude::{Children, Parent, Transform};
 use bevy_utils::HashMap;
-use bevy_window::{Window, WindowId, Windows};
+use bevy_window::{Window, WindowId, WindowScaleFactorChanged, Windows};
 use std::fmt;
 use stretch::{number::Number, Stretch};
 
@@ -161,11 +162,15 @@ impl FlexSurface {
 unsafe impl Send for FlexSurface {}
 unsafe impl Sync for FlexSurface {}
 
+#[allow(clippy::too_many_arguments)]
 pub fn flex_node_system(
     windows: Res<Windows>,
+    mut scale_factor_reader: Local<EventReader<WindowScaleFactorChanged>>,
+    scale_factor_events: Res<Events<WindowScaleFactorChanged>>,
     mut flex_surface: ResMut<FlexSurface>,
     root_node_query: Query<Entity, (With<Node>, Without<Parent>)>,
     node_query: Query<(Entity, &Style, Option<&CalculatedSize>), (With<Node>, Changed<Style>)>,
+    full_node_query: Query<(Entity, &Style, Option<&CalculatedSize>), With<Node>>,
     changed_size_query: Query<
         (Entity, &Style, &CalculatedSize),
         (With<Node>, Changed<CalculatedSize>),
@@ -185,13 +190,31 @@ pub fn flex_node_system(
         1.
     };
 
-    // update changed nodes
-    for (entity, style, calculated_size) in node_query.iter() {
-        // TODO: remove node from old hierarchy if its root has changed
-        if let Some(calculated_size) = calculated_size {
-            flex_surface.upsert_leaf(entity, &style, *calculated_size, logical_to_physical_factor);
-        } else {
-            flex_surface.upsert_node(entity, &style, logical_to_physical_factor);
+    if scale_factor_reader.latest(&scale_factor_events).is_some() {
+        update_changed(
+            &mut *flex_surface,
+            logical_to_physical_factor,
+            full_node_query,
+        );
+    } else {
+        update_changed(&mut *flex_surface, logical_to_physical_factor, node_query);
+    }
+
+    fn update_changed<F>(
+        flex_surface: &mut FlexSurface,
+        scaling_factor: f64,
+        query: Query<(Entity, &Style, Option<&CalculatedSize>), F>,
+    ) where
+        F: QueryFilter,
+    {
+        // update changed nodes
+        for (entity, style, calculated_size) in query.iter() {
+            // TODO: remove node from old hierarchy if its root has changed
+            if let Some(calculated_size) = calculated_size {
+                flex_surface.upsert_leaf(entity, &style, *calculated_size, scaling_factor);
+            } else {
+                flex_surface.upsert_node(entity, &style, scaling_factor);
+            }
         }
     }
 

crates/bevy_window/src/event.rs

@@ -64,3 +64,16 @@ pub struct WindowFocused {
     pub id: WindowId,
     pub focused: bool,
 }
+
+/// An event that indicates a window's scale factor has changed.
+#[derive(Debug, Clone)]
+pub struct WindowScaleFactorChanged {
+    pub id: WindowId,
+    pub scale_factor: f64,
+}
+/// An event that indicates a window's OS-reported scale factor has changed.
+#[derive(Debug, Clone)]
+pub struct WindowBackendScaleFactorChanged {
+    pub id: WindowId,
+    pub scale_factor: f64,
+}

crates/bevy_window/src/lib.rs

@@ -44,6 +44,8 @@ impl Plugin for WindowPlugin {
             .add_event::<CursorLeft>()
             .add_event::<ReceivedCharacter>()
             .add_event::<WindowFocused>()
+            .add_event::<WindowScaleFactorChanged>()
+            .add_event::<WindowBackendScaleFactorChanged>()
             .init_resource::<Windows>();
 
         if self.add_primary_window {

crates/bevy_window/src/window.rs

@@ -54,7 +54,8 @@ pub struct Window {
     requested_height: f32,
     physical_width: u32,
     physical_height: u32,
-    scale_factor: f64,
+    scale_factor_override: Option<f64>,
+    backend_scale_factor: f64,
     title: String,
     vsync: bool,
     resizable: bool,
@@ -77,8 +78,12 @@ pub enum WindowCommand {
     SetTitle {
         title: String,
     },
+    SetScaleFactor {
+        scale_factor: f64,
+    },
     SetResolution {
-        resolution: (f32, f32),
+        logical_resolution: (f32, f32),
+        scale_factor: f64,
     },
     SetVsync {
         vsync: bool,
@@ -129,7 +134,8 @@ impl Window {
             requested_height: window_descriptor.height,
             physical_width,
             physical_height,
-            scale_factor,
+            scale_factor_override: window_descriptor.scale_factor_override,
+            backend_scale_factor: scale_factor,
             title: window_descriptor.title.clone(),
             vsync: window_descriptor.vsync,
             resizable: window_descriptor.resizable,
@@ -152,13 +158,13 @@ impl Window {
     /// The current logical width of the window's client area.
     #[inline]
     pub fn width(&self) -> f32 {
-        (self.physical_width as f64 / self.scale_factor) as f32
+        (self.physical_width as f64 / self.scale_factor()) as f32
     }
 
     /// The current logical height of the window's client area.
     #[inline]
     pub fn height(&self) -> f32 {
-        (self.physical_height as f64 / self.scale_factor) as f32
+        (self.physical_height as f64 / self.scale_factor()) as f32
     }
 
     /// The requested window client area width in logical pixels from window
@@ -201,18 +207,40 @@ impl Window {
 
     /// Request the OS to resize the window such the the client area matches the
     /// specified width and height.
+    #[allow(clippy::float_cmp)]
     pub fn set_resolution(&mut self, width: f32, height: f32) {
+        if self.requested_width == width && self.requested_height == height {
+            return;
+        }
         self.requested_width = width;
         self.requested_height = height;
         self.command_queue.push(WindowCommand::SetResolution {
-            resolution: (self.requested_width, self.requested_height),
+            logical_resolution: (self.requested_width, self.requested_height),
+            scale_factor: self.scale_factor(),
+        });
+    }
+
+    /// Override the os-reported scaling factor
+    #[allow(clippy::float_cmp)]
+    pub fn set_scale_factor_override(&mut self, scale_factor: Option<f64>) {
+        if self.scale_factor_override == scale_factor {
+            return;
+        }
+
+        self.scale_factor_override = scale_factor;
+        self.command_queue.push(WindowCommand::SetScaleFactor {
+            scale_factor: self.scale_factor(),
+        });
+        self.command_queue.push(WindowCommand::SetResolution {
+            logical_resolution: (self.requested_width, self.requested_height),
+            scale_factor: self.scale_factor(),
         });
     }
 
     #[allow(missing_docs)]
     #[inline]
     pub fn update_scale_factor_from_backend(&mut self, scale_factor: f64) {
-        self.scale_factor = scale_factor;
+        self.backend_scale_factor = scale_factor;
     }
 
     #[allow(missing_docs)]
@@ -225,9 +253,21 @@ impl Window {
     /// The ratio of physical pixels to logical pixels
     ///
     /// `physical_pixels = logical_pixels * scale_factor`
-    #[inline]
     pub fn scale_factor(&self) -> f64 {
-        self.scale_factor
+        self.scale_factor_override
+            .unwrap_or(self.backend_scale_factor)
+    }
+
+    /// The window scale factor as reported by the window backend.
+    /// This value is unaffected by scale_factor_override.
+    #[inline]
+    pub fn backend_scale_factor(&self) -> f64 {
+        self.backend_scale_factor
+    }
+
+    #[inline]
+    pub fn scale_factor_override(&self) -> Option<f64> {
+        self.scale_factor_override
     }
 
     #[inline]
@@ -335,6 +375,7 @@ impl Window {
 pub struct WindowDescriptor {
     pub width: f32,
     pub height: f32,
+    pub scale_factor_override: Option<f64>,
     pub title: String,
     pub vsync: bool,
     pub resizable: bool,
@@ -352,6 +393,7 @@ impl Default for WindowDescriptor {
             title: "bevy".to_string(),
             width: 1280.,
             height: 720.,
+            scale_factor_override: None,
             vsync: true,
             resizable: true,
             decorations: true,

crates/bevy_winit/src/lib.rs

@@ -14,8 +14,9 @@ use bevy_ecs::{IntoSystem, Resources, World};
 use bevy_math::Vec2;
 use bevy_utils::tracing::{error, trace, warn};
 use bevy_window::{
-    CreateWindow, CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter, WindowCloseRequested,
-    WindowCreated, WindowFocused, WindowResized, Windows,
+    CreateWindow, CursorEntered, CursorLeft, CursorMoved, ReceivedCharacter,
+    WindowBackendScaleFactorChanged, WindowCloseRequested, WindowCreated, WindowFocused,
+    WindowResized, WindowScaleFactorChanged, Windows,
 };
 use winit::{
     event::{self, DeviceEvent, Event, WindowEvent},
@@ -76,14 +77,21 @@ fn change_window(_: &mut World, resources: &mut Resources) {
                     let window = winit_windows.get_window(id).unwrap();
                     window.set_title(&title);
                 }
+                bevy_window::WindowCommand::SetScaleFactor { scale_factor } => {
+                    let mut window_dpi_changed_events = resources
+                        .get_mut::<Events<WindowScaleFactorChanged>>()
+                        .unwrap();
+                    window_dpi_changed_events.send(WindowScaleFactorChanged { id, scale_factor });
+                }
                 bevy_window::WindowCommand::SetResolution {
-                    resolution: (logical_width, logical_height),
+                    logical_resolution: (width, height),
+                    scale_factor,
                 } => {
                     let window = winit_windows.get_window(id).unwrap();
-                    window.set_inner_size(winit::dpi::LogicalSize::new(
-                        logical_width,
-                        logical_height,
-                    ));
+                    window.set_inner_size(
+                        winit::dpi::LogicalSize::new(width, height)
+                            .to_physical::<f64>(scale_factor),
+                    );
                 }
                 bevy_window::WindowCommand::SetVsync { .. } => (),
                 bevy_window::WindowCommand::SetResizable { resizable } => {
@@ -342,13 +350,44 @@ pub fn winit_runner_with(mut app: App, mut event_loop: EventLoop<()>) {
                         scale_factor,
                         new_inner_size,
                     } => {
+                        let mut backend_scale_factor_change_events = app
+                            .resources
+                            .get_mut::<Events<WindowBackendScaleFactorChanged>>()
+                            .unwrap();
+                        backend_scale_factor_change_events.send(WindowBackendScaleFactorChanged {
+                            id: window_id,
+                            scale_factor,
+                        });
+                        #[allow(clippy::float_cmp)]
+                        if window.scale_factor() != scale_factor {
+                            let mut scale_factor_change_events = app
+                                .resources
+                                .get_mut::<Events<WindowScaleFactorChanged>>()
+                                .unwrap();
+
+                            scale_factor_change_events.send(WindowScaleFactorChanged {
+                                id: window_id,
+                                scale_factor,
+                            });
+                        }
+
+                        window.update_scale_factor_from_backend(scale_factor);
+
+                        if window.physical_width() != new_inner_size.width
+                            || window.physical_height() != new_inner_size.height
+                        {
+                            let mut resize_events =
+                                app.resources.get_mut::<Events<WindowResized>>().unwrap();
+                            resize_events.send(WindowResized {
+                                id: window_id,
+                                width: window.width(),
+                                height: window.height(),
+                            });
+                        }
                         window.update_actual_size_from_backend(
                             new_inner_size.width,
                             new_inner_size.height,
                         );
-                        window.update_scale_factor_from_backend(scale_factor);
-                        // should we send a resize event to indicate the change in
-                        // logical size?
                     }
                     WindowEvent::Focused(focused) => {
                         let mut focused_events =

crates/bevy_winit/src/winit_windows.rs

@@ -38,13 +38,24 @@ impl WinitWindows {
                     false => get_best_videomode(&event_loop.primary_monitor().unwrap()),
                 }),
             )),
-            _ => winit_window_builder
-                .with_inner_size(winit::dpi::LogicalSize::new(
-                    window_descriptor.width,
-                    window_descriptor.height,
-                ))
-                .with_resizable(window_descriptor.resizable)
-                .with_decorations(window_descriptor.decorations),
+            _ => {
+                let WindowDescriptor {
+                    width,
+                    height,
+                    scale_factor_override,
+                    ..
+                } = window_descriptor;
+                if let Some(sf) = scale_factor_override {
+                    winit_window_builder.with_inner_size(
+                        winit::dpi::LogicalSize::new(*width, *height).to_physical::<f64>(*sf),
+                    )
+                } else {
+                    winit_window_builder
+                        .with_inner_size(winit::dpi::LogicalSize::new(*width, *height))
+                }
+            }
+            .with_resizable(window_descriptor.resizable)
+            .with_decorations(window_descriptor.decorations),
         };
 
         #[allow(unused_mut)]