From 0b9bb5f494bb033b9db1a5576efb8dfe3288001e Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emil.ernerfeldt@gmail.com>
Date: Wed, 5 Nov 2025 10:35:57 +0100
Subject: [PATCH] Make sure `native_pixels_per_point` is set during app
 creation (#7683)

Useful for things like analytics
---
 crates/eframe/src/native/glow_integration.rs | 18 ++++++++++++++---
 crates/eframe/src/native/wgpu_integration.rs | 21 ++++++++++++++++----
 crates/eframe/src/web/app_runner.rs          |  8 ++++++++
 3 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/crates/eframe/src/native/glow_integration.rs b/crates/eframe/src/native/glow_integration.rs
index 4a3bee46..b4267405 100644
--- a/crates/eframe/src/native/glow_integration.rs
+++ b/crates/eframe/src/native/glow_integration.rs
@@ -1041,11 +1041,23 @@ impl GlutinWindowContext {
 
         let mut viewport_from_window = HashMap::default();
         let mut window_from_viewport = OrderedViewportIdMap::default();
-        let mut info = ViewportInfo::default();
+        let mut viewport_info = ViewportInfo::default();
         if let Some(window) = &window {
             viewport_from_window.insert(window.id(), ViewportId::ROOT);
             window_from_viewport.insert(ViewportId::ROOT, window.id());
-            egui_winit::update_viewport_info(&mut info, egui_ctx, window, true);
+            egui_winit::update_viewport_info(&mut viewport_info, egui_ctx, window, true);
+
+            // Tell egui right away about native_pixels_per_point etc,
+            // so that the app knows about it during app creation:
+            let pixels_per_point = egui_winit::pixels_per_point(egui_ctx, window);
+
+            egui_ctx.input_mut(|i| {
+                i.raw
+                    .viewports
+                    .insert(ViewportId::ROOT, viewport_info.clone());
+
+                i.pixels_per_point = pixels_per_point;
+            });
         }
 
         let mut viewports = OrderedViewportIdMap::default();
@@ -1056,7 +1068,7 @@ impl GlutinWindowContext {
                 class: ViewportClass::Root,
                 builder: viewport_builder,
                 deferred_commands: vec![],
-                info,
+                info: viewport_info,
                 actions_requested: Default::default(),
                 viewport_ui_cb: None,
                 gl_surface: None,
diff --git a/crates/eframe/src/native/wgpu_integration.rs b/crates/eframe/src/native/wgpu_integration.rs
index b21b62ac..c6c715c8 100644
--- a/crates/eframe/src/native/wgpu_integration.rs
+++ b/crates/eframe/src/native/wgpu_integration.rs
@@ -199,6 +199,22 @@ impl<'app> WgpuWinitApp<'app> {
             },
         ));
 
+        let mut viewport_info = ViewportInfo::default();
+        egui_winit::update_viewport_info(&mut viewport_info, &egui_ctx, &window, true);
+
+        {
+            // Tell egui right away about native_pixels_per_point etc,
+            // so that the app knows about it during app creation:
+            let pixels_per_point = egui_winit::pixels_per_point(&egui_ctx, &window);
+
+            egui_ctx.input_mut(|i| {
+                i.raw
+                    .viewports
+                    .insert(ViewportId::ROOT, viewport_info.clone());
+                i.pixels_per_point = pixels_per_point;
+            });
+        }
+
         let window = Arc::new(window);
 
         {
@@ -278,9 +294,6 @@ impl<'app> WgpuWinitApp<'app> {
         let mut viewport_from_window = HashMap::default();
         viewport_from_window.insert(window.id(), ViewportId::ROOT);
 
-        let mut info = ViewportInfo::default();
-        egui_winit::update_viewport_info(&mut info, &egui_ctx, &window, true);
-
         let mut viewports = Viewports::default();
         viewports.insert(
             ViewportId::ROOT,
@@ -289,7 +302,7 @@ impl<'app> WgpuWinitApp<'app> {
                 class: ViewportClass::Root,
                 builder,
                 deferred_commands: vec![],
-                info,
+                info: viewport_info,
                 actions_requested: Default::default(),
                 viewport_ui_cb: None,
                 window: Some(window),
diff --git a/crates/eframe/src/web/app_runner.rs b/crates/eframe/src/web/app_runner.rs
index bd245a1f..4a97235a 100644
--- a/crates/eframe/src/web/app_runner.rs
+++ b/crates/eframe/src/web/app_runner.rs
@@ -65,6 +65,14 @@ impl AppRunner {
             o.zoom_factor = 1.0;
         });
 
+        // Tell egui right away about native_pixels_per_point
+        // so that the app knows about it during app creation:
+        egui_ctx.input_mut(|i| {
+            let viewport_info = i.raw.viewports.entry(egui::ViewportId::ROOT).or_default();
+            viewport_info.native_pixels_per_point = Some(super::native_pixels_per_point());
+            i.pixels_per_point = super::native_pixels_per_point();
+        });
+
         let cc = epi::CreationContext {
             egui_ctx: egui_ctx.clone(),
             integration_info: info.clone(),