4 files changed, 14 insertions, 6 deletions
diff --git a/examples/multi_window/src/main.rs b/examples/multi_window/src/main.rs
index 18536bdf..0d0a809b 100644
--- a/examples/multi_window/src/main.rs
+++ b/examples/multi_window/src/main.rs
@@ -12,6 +12,7 @@ use iced::{Color, Command, Element, Length, Settings, Size, Subscription};
 use iced_lazy::responsive;
 use iced_native::{event, subscription, Event};
 
+use iced_native::window::Id;
 use std::collections::HashMap;
 
 pub fn main() -> iced::Result {
@@ -29,6 +30,7 @@ struct Example {
 #[derive(Debug)]
 struct Window {
     title: String,
+    scale: f64,
     panes: pane_grid::State<Pane>,
     focus: Option<pane_grid::Pane>,
 }
@@ -69,6 +71,7 @@ impl Application for Example {
             panes,
             focus: None,
             title: String::from("Default window"),
+            scale: 1.0,
         };
 
         (
@@ -178,6 +181,7 @@ impl Application for Example {
                         panes,
                         focus: None,
                         title: format!("New window ({})", self.windows.len()),
+                        scale: 1.0 + (self.windows.len() as f64 / 10.0),
                     };
 
                     let window_id = window::Id::new(self.windows.len());
@@ -342,6 +346,10 @@ impl Application for Example {
     fn close_requested(&self, window: window::Id) -> Self::Message {
         Message::Window(window, WindowMessage::CloseWindow)
     }
+
+    fn scale_factor(&self, window: Id) -> f64 {
+        self.windows.get(&window).map(|w| w.scale).unwrap_or(1.0)
+    }
 }
 
 const PANE_ID_COLOR_UNFOCUSED: Color = Color::from_rgb(
diff --git a/src/multi_window/application.rs b/src/multi_window/application.rs
index 3f20382c..3af1d8d5 100644
--- a/src/multi_window/application.rs
+++ b/src/multi_window/application.rs
@@ -148,7 +148,7 @@ pub trait Application: Sized {
     /// while a scale factor of `0.5` will shrink them to half their size.
     ///
     /// By default, it returns `1.0`.
-    fn scale_factor(&self) -> f64 {
+    fn scale_factor(&self, window: window::Id) -> f64 {
         1.0
     }
 
@@ -239,8 +239,8 @@ where
         self.0.subscription()
     }
 
-    fn scale_factor(&self) -> f64 {
-        self.0.scale_factor()
+    fn scale_factor(&self, window: window::Id) -> f64 {
+        self.0.scale_factor(window)
     }
 
     fn should_exit(&self) -> bool {
diff --git a/winit/src/multi_window.rs b/winit/src/multi_window.rs
index d7378a1d..ad65e6a5 100644
--- a/winit/src/multi_window.rs
+++ b/winit/src/multi_window.rs
@@ -146,7 +146,7 @@ where
     /// while a scale factor of `0.5` will shrink them to half their size.
     ///
     /// By default, it returns `1.0`.
-    fn scale_factor(&self) -> f64 {
+    fn scale_factor(&self, window: window::Id) -> f64 {
         1.0
     }
 
diff --git a/winit/src/multi_window/state.rs b/winit/src/multi_window/state.rs
index 2c2a4693..35c69924 100644
--- a/winit/src/multi_window/state.rs
+++ b/winit/src/multi_window/state.rs
@@ -36,7 +36,7 @@ where
         window: &Window,
     ) -> Self {
         let title = application.title(window_id);
-        let scale_factor = application.scale_factor();
+        let scale_factor = application.scale_factor(window_id);
         let theme = application.theme();
         let appearance = theme.appearance(&application.style());
 
@@ -199,7 +199,7 @@ where
         }
 
         // Update scale factor
-        let new_scale_factor = application.scale_factor();
+        let new_scale_factor = application.scale_factor(window_id);
 
         if self.scale_factor != new_scale_factor {
             let size = window.inner_size();