Expose Raw Window and Display Handles (#3073)

* Expose raw window and display handles in eframe

* Ensure that no one implements `Clone` in the future

* Cleanup

---------

Co-authored-by: Matti Virkkunen <mvirkkunen@gmail.com>

Cargo.lock

@@ -1164,6 +1164,7 @@ dependencies = [
  "raw-window-handle",
  "ron",
  "serde",
+ "static_assertions",
  "thiserror",
  "tts",
  "wasm-bindgen",

crates/eframe/CHANGELOG.md

@@ -5,7 +5,7 @@ NOTE: [`egui-winit`](../egui-winit/CHANGELOG.md), [`egui_glium`](../egui_glium/C
 
 
 ## Unreleased
-
+* Expose raw window and display handles in `CreationContext` and `Frame`
 
 ## 0.22.0 - 2023-05-23
 * Fix: `request_repaint_after` works even when called from background thread [#2939](https://github.com/emilk/egui/pull/2939)

crates/eframe/Cargo.toml

@@ -96,6 +96,7 @@ egui_glow = { version = "0.22.0", path = "../egui_glow", optional = true, defaul
 glow = { version = "0.12", optional = true }
 ron = { version = "0.8", optional = true, features = ["integer128"] }
 serde = { version = "1", optional = true, features = ["derive"] }
+static_assertions = "1.1.0"
 
 # -------------------------------------------
 # native:

crates/eframe/src/epi/mod.rs

@@ -19,6 +19,13 @@ use std::any::Any;
 #[cfg(any(feature = "glow", feature = "wgpu"))]
 pub use crate::native::run::UserEvent;
 
+#[cfg(not(target_arch = "wasm32"))]
+use raw_window_handle::{
+    HasRawDisplayHandle, HasRawWindowHandle, RawDisplayHandle, RawWindowHandle,
+};
+#[cfg(not(target_arch = "wasm32"))]
+use static_assertions::assert_not_impl_any;
+
 #[cfg(not(target_arch = "wasm32"))]
 #[cfg(any(feature = "glow", feature = "wgpu"))]
 pub use winit::event_loop::EventLoopBuilder;
@@ -64,6 +71,34 @@ pub struct CreationContext<'s> {
     /// Can be used to manage GPU resources for custom rendering with WGPU using [`egui::PaintCallback`]s.
     #[cfg(feature = "wgpu")]
     pub wgpu_render_state: Option<egui_wgpu::RenderState>,
+
+    /// Raw platform window handle
+    #[cfg(not(target_arch = "wasm32"))]
+    pub(crate) raw_window_handle: RawWindowHandle,
+
+    /// Raw platform display handle for window
+    #[cfg(not(target_arch = "wasm32"))]
+    pub(crate) raw_display_handle: RawDisplayHandle,
+}
+
+// Implementing `Clone` would violate the guarantees of `HasRawWindowHandle` and `HasRawDisplayHandle`.
+#[cfg(not(target_arch = "wasm32"))]
+assert_not_impl_any!(CreationContext<'_>: Clone);
+
+#[allow(unsafe_code)]
+#[cfg(not(target_arch = "wasm32"))]
+unsafe impl HasRawWindowHandle for CreationContext<'_> {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        self.raw_window_handle
+    }
+}
+
+#[allow(unsafe_code)]
+#[cfg(not(target_arch = "wasm32"))]
+unsafe impl HasRawDisplayHandle for CreationContext<'_> {
+    fn raw_display_handle(&self) -> RawDisplayHandle {
+        self.raw_display_handle
+    }
 }
 
 // ----------------------------------------------------------------------------
@@ -695,6 +730,34 @@ pub struct Frame {
     /// such that it can be retrieved during [`App::post_rendering`] with [`Frame::screenshot`]
     #[cfg(not(target_arch = "wasm32"))]
     pub(crate) screenshot: std::cell::Cell<Option<egui::ColorImage>>,
+
+    /// Raw platform window handle
+    #[cfg(not(target_arch = "wasm32"))]
+    pub(crate) raw_window_handle: RawWindowHandle,
+
+    /// Raw platform display handle for window
+    #[cfg(not(target_arch = "wasm32"))]
+    pub(crate) raw_display_handle: RawDisplayHandle,
+}
+
+// Implementing `Clone` would violate the guarantees of `HasRawWindowHandle` and `HasRawDisplayHandle`.
+#[cfg(not(target_arch = "wasm32"))]
+assert_not_impl_any!(Frame: Clone);
+
+#[allow(unsafe_code)]
+#[cfg(not(target_arch = "wasm32"))]
+unsafe impl HasRawWindowHandle for Frame {
+    fn raw_window_handle(&self) -> RawWindowHandle {
+        self.raw_window_handle
+    }
+}
+
+#[allow(unsafe_code)]
+#[cfg(not(target_arch = "wasm32"))]
+unsafe impl HasRawDisplayHandle for Frame {
+    fn raw_display_handle(&self) -> RawDisplayHandle {
+        self.raw_display_handle
+    }
 }
 
 impl Frame {

crates/eframe/src/native/epi_integration.rs

@@ -3,6 +3,8 @@ use winit::event_loop::EventLoopWindowTarget;
 #[cfg(target_os = "macos")]
 use winit::platform::macos::WindowBuilderExtMacOS as _;
 
+use raw_window_handle::{HasRawDisplayHandle as _, HasRawWindowHandle as _};
+
 #[cfg(feature = "accesskit")]
 use egui::accesskit;
 use egui::NumExt as _;
@@ -380,6 +382,8 @@ impl EpiIntegration {
             #[cfg(feature = "wgpu")]
             wgpu_render_state,
             screenshot: std::cell::Cell::new(None),
+            raw_display_handle: window.raw_display_handle(),
+            raw_window_handle: window.raw_window_handle(),
         };
 
         let mut egui_winit = egui_winit::State::new(event_loop);

crates/eframe/src/native/run.rs

@@ -3,6 +3,7 @@
 
 use std::time::Instant;
 
+use raw_window_handle::{HasRawDisplayHandle as _, HasRawWindowHandle as _};
 use winit::event_loop::{
     ControlFlow, EventLoop, EventLoopBuilder, EventLoopProxy, EventLoopWindowTarget,
 };
@@ -345,7 +346,6 @@ mod glow_integration {
         prelude::{GlDisplay, NotCurrentGlContextSurfaceAccessor, PossiblyCurrentGlContext},
         surface::GlSurface,
     };
-    use raw_window_handle::HasRawWindowHandle;
 
     use super::*;
 
@@ -756,6 +756,8 @@ mod glow_integration {
                 gl: Some(gl.clone()),
                 #[cfg(feature = "wgpu")]
                 wgpu_render_state: None,
+                raw_display_handle: gl_window.window().raw_display_handle(),
+                raw_window_handle: gl_window.window().raw_window_handle(),
             });
 
             if app.warm_up_enabled() {
@@ -1215,6 +1217,8 @@ mod wgpu_integration {
                 #[cfg(feature = "glow")]
                 gl: None,
                 wgpu_render_state,
+                raw_display_handle: window.raw_display_handle(),
+                raw_window_handle: window.raw_window_handle(),
             });
 
             if app.warm_up_enabled() {