Add support for raw-window-handle (#4918)

Add a `raw-window-handle-06` feature to the Rust API crates, which adds support for version 0.6 of rwh to slint::Window, by delegation adding a `window_handle()` function that returns a struct that implements the corresponding traits from rwh.

HasDisplayHandle could also be provided on the backend, but that can be
done separately if needed.

This is only implemented for the winit backend right now.

cc #877

.github/workflows/build_docs.yaml

@@ -22,7 +22,7 @@ jobs:
             - name: Set up rgb crate rustdoc link
               run: |
                   rgb_version=`grep 'rgb = '  internal/core/Cargo.toml | sed 's/^.*"\(.*\)"/\1/'`
-                  echo "RUSTDOCFLAGS=$RUSTDOCFLAGS --extern-html-root-url rgb=https://docs.rs/rgb/$rgb_version/ --extern-html-root-url android_activity=https://docs.rs/android-activity/0.5/ -Z unstable-options" >> $GITHUB_ENV
+                  echo "RUSTDOCFLAGS=$RUSTDOCFLAGS --extern-html-root-url rgb=https://docs.rs/rgb/$rgb_version/ --extern-html-root-url android_activity=https://docs.rs/android-activity/0.5/ --extern-html-root-url raw_window_handle=https://docs.rs/raw_window_handle/0.6 -Z unstable-options" >> $GITHUB_ENV
             - uses: ./.github/actions/install-nodejs
             - name: Cache mdbook and mdbook-linkcheck
               uses: actions/cache@v4

Cargo.toml

@@ -140,6 +140,8 @@ strum = { version = "0.26.1", default-features = false, features = ["derive"] }
 toml_edit = { version = "0.22.7" }
 cfg_aliases = { version = "0.2.0" }
 
+raw-window-handle-06 = { package = "raw-window-handle", version = "0.6", features = ["alloc"] }
+
 [profile.release]
 lto = true
 panic = "abort"

api/rs/slint/Cargo.toml

@@ -78,6 +78,12 @@ unsafe-single-threaded = ["i-slint-core/unsafe-single-threaded"]
 ## APIs to support screen readers and other assistive technologies.
 accessibility = ["i-slint-backend-selector/accessibility"]
 
+## Enable integration with [raw-window-handle](raw_window_handle_06) version 0.6. This provides a
+## [`Window::window_handle()`] function that returns a struct that implements
+## [HasWindowHandle](raw_window_handle_06::HasWindowHandle) and
+## [HasDisplayHandle](raw_window_handle_06::HasDisplayHandle) implementation.
+raw-window-handle-06 = ["dep:raw-window-handle-06", "i-slint-backend-selector/raw-window-handle-06"]
+
 #! ### Backends
 
 #! Slint needs a backend that will act as liaison between Slint and the OS.
@@ -175,6 +181,8 @@ num-traits = { version = "0.2", default-features = false }
 
 log = { version = "0.4.17", optional = true }
 
+raw-window-handle-06 = { workspace = true, optional = true }
+
 [target.'cfg(not(target_os = "android"))'.dependencies]
 # FemtoVG is disabled on android because it doesn't compile without setting RUST_FONTCONFIG_DLOPEN=on
 # end even then wouldn't work because it can't load fonts
@@ -200,4 +208,4 @@ rustdoc-args = [
   "--html-in-header",
   "docs/resources/slint-docs-highlight.html",
 ]
-features = ["document-features", "log", "gettext", "renderer-software", "renderer-femtovg"]
+features = ["document-features", "log", "gettext", "renderer-software", "renderer-femtovg", "raw-window-handle-06"]

internal/backends/selector/Cargo.toml

@@ -32,6 +32,8 @@ renderer-software = ["i-slint-backend-winit?/renderer-software", "i-slint-core/s
 rtti = ["i-slint-core/rtti", "i-slint-backend-qt?/rtti"]
 accessibility = ["i-slint-backend-winit?/accessibility"]
 
+raw-window-handle-06 = ["i-slint-core/raw-window-handle-06", "i-slint-backend-winit?/raw-window-handle-06"]
+
 # note that default enable the i-slint-backend-qt, but not its enable feature
 default = ["i-slint-backend-qt", "backend-winit"]
 

internal/backends/winit/Cargo.toml

@@ -27,6 +27,7 @@ renderer-skia-opengl = ["renderer-skia", "i-slint-renderer-skia/opengl"]
 renderer-skia-vulkan = ["renderer-skia", "i-slint-renderer-skia/vulkan"]
 renderer-software = ["dep:softbuffer", "dep:imgref", "dep:rgb", "i-slint-core/software-renderer-systemfonts", "dep:bytemuck", "winit/rwh_05"]
 accessibility = ["dep:accesskit", "dep:accesskit_winit"]
+raw-window-handle-06 = ["dep:raw-window-handle-06", "winit/rwh_06"]
 default = []
 
 [dependencies]
@@ -58,6 +59,8 @@ imgref = { version = "1.6.1", optional = true }
 rgb = { version = "0.8.27", optional = true }
 bytemuck = { workspace = true, optional = true, features = ["derive"] }
 
+raw-window-handle-06 = { workspace = true, optional = true }
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 web-sys = { version = "0.3", features=["HtmlInputElement", "HtmlCanvasElement", "Window", "Document", "Event", "KeyboardEvent", "InputEvent", "CompositionEvent", "DomStringMap", "ClipboardEvent", "DataTransfer"] }
 wasm-bindgen = { version = "0.2" }
@@ -77,7 +80,7 @@ cocoa = { version = "0.25.0" }
 cfg_aliases = { workspace = true }
 
 [dev-dependencies]
-slint = { path = "../../../api/rs/slint", default-features = false, features = ["std", "compat-1-2", "backend-winit", "renderer-software"] }
+slint = { path = "../../../api/rs/slint", default-features = false, features = ["std", "compat-1-2", "backend-winit", "renderer-software", "raw-window-handle-06"] }
 
 [package.metadata.docs.rs]
 features = ["wayland", "renderer-software"]

internal/backends/winit/lib.rs

@@ -408,11 +408,15 @@ mod testui {
 // Sorry, can't test with rust test harness and multiple threads.
 #[cfg(not(any(target_arch = "wasm32", target_os = "macos", target_os = "ios")))]
 #[test]
-fn test_window_accessor() {
+fn test_window_accessor_and_rwh() {
     slint::platform::set_platform(Box::new(crate::Backend::new().unwrap())).unwrap();
 
     use testui::*;
     let app = App::new().unwrap();
     let slint_window = app.window();
     assert!(slint_window.has_winit_window());
+    let handle = slint_window.window_handle();
+    use raw_window_handle_06::{HasDisplayHandle, HasWindowHandle};
+    assert!(handle.window_handle().is_ok());
+    assert!(handle.display_handle().is_ok());
 }

internal/backends/winit/winitwindowadapter.rs

@@ -617,6 +617,20 @@ impl WindowAdapter for WinitWindowAdapter {
     fn internal(&self, _: corelib::InternalToken) -> Option<&dyn WindowAdapterInternal> {
         Some(self)
     }
+
+    #[cfg(feature = "raw-window-handle-06")]
+    fn window_handle_06(
+        &self,
+    ) -> Result<raw_window_handle_06::WindowHandle<'_>, raw_window_handle_06::HandleError> {
+        raw_window_handle_06::HasWindowHandle::window_handle(&self.winit_window)
+    }
+
+    #[cfg(feature = "raw-window-handle-06")]
+    fn display_handle_06(
+        &self,
+    ) -> Result<raw_window_handle_06::DisplayHandle<'_>, raw_window_handle_06::HandleError> {
+        raw_window_handle_06::HasDisplayHandle::display_handle(&self.winit_window)
+    }
 }
 
 impl WindowAdapterInternal for WinitWindowAdapter {

internal/core/Cargo.toml

@@ -24,7 +24,7 @@ libm = ["num-traits/libm", "euclid/libm"]
 # Allow the viewer to query at runtime information about item types
 rtti = []
 # Use the standard library
-std = ["euclid/std", "once_cell/std", "scoped-tls-hkt", "lyon_path", "lyon_algorithms", "lyon_geom", "lyon_extra", "dep:web-time", "image-decoders", "svg"]
+std = ["euclid/std", "once_cell/std", "scoped-tls-hkt", "lyon_path", "lyon_algorithms", "lyon_geom", "lyon_extra", "dep:web-time", "image-decoders", "svg", "raw-window-handle-06?/std"]
 # Unsafe feature meaning that there is only one core running and all thread_local are static.
 # You can only enable this feature if you are sure that any API of this crate is only called
 # from a single core, and not in a interrupt or signal handler.
@@ -44,6 +44,8 @@ box-shadow-cache = []
 
 shared-fontdb = ["i-slint-common/shared-fontdb"]
 
+raw-window-handle-06 = ["dep:raw-window-handle-06"]
+
 default = ["std", "unicode"]
 
 [dependencies]
@@ -86,6 +88,8 @@ resvg = { workspace = true, optional = true }
 fontdb = { workspace = true, optional = true }
 serde = { version = "1.0.163", features = ["derive"], optional = true }
 
+raw-window-handle-06 = { workspace = true, optional = true }
+
 [target.'cfg(target_family = "unix")'.dependencies]
 gettext-rs = { version = "0.7", optional = true, features = ["gettext-system"] }
 
@@ -107,4 +111,4 @@ ttf-parser = "0.20.0"
 fontdb = { workspace = true, default-features = true }
 serde_json = "1.0.96"
 tiny-skia = "0.11.0"
-tokio = { version = "1.35", features = ["rt-multi-thread"] }
+tokio = { version = "1.35", features = ["rt-multi-thread"] }

internal/core/api.rs

@@ -324,6 +324,34 @@ pub enum SetRenderingNotifierError {
     AlreadySet,
 }
 
+/// This struct represents a persistent handle to a window and implements the
+/// [`raw_window_handle_06::HasWindowHandle`] and [`raw_window_handle_06::HasDisplayHandle`]
+/// traits for accessing exposing raw window and display handles.
+/// Obtain an instance of this by calling [`Window::window_handle()`].
+#[cfg(feature = "raw-window-handle-06")]
+#[derive(Clone)]
+pub struct WindowHandle {
+    adapter: alloc::rc::Rc<dyn WindowAdapter>,
+}
+
+#[cfg(feature = "raw-window-handle-06")]
+impl raw_window_handle_06::HasWindowHandle for WindowHandle {
+    fn window_handle<'a>(
+        &'a self,
+    ) -> Result<raw_window_handle_06::WindowHandle<'a>, raw_window_handle_06::HandleError> {
+        self.adapter.window_handle_06()
+    }
+}
+
+#[cfg(feature = "raw-window-handle-06")]
+impl raw_window_handle_06::HasDisplayHandle for WindowHandle {
+    fn display_handle<'a>(
+        &'a self,
+    ) -> Result<raw_window_handle_06::DisplayHandle<'a>, raw_window_handle_06::HandleError> {
+        self.adapter.display_handle_06()
+    }
+}
+
 /// This type represents a window towards the windowing system, that's used to render the
 /// scene of a component. It provides API to control windowing system specific aspects such
 /// as the position on the screen.
@@ -571,6 +599,13 @@ impl Window {
     pub fn is_visible(&self) -> bool {
         self.0.is_visible()
     }
+
+    /// Returns a struct that implements the raw window handle traits to access the windowing system specific window
+    /// and display handles. This function is only accessible if you enable the `raw-window-handle-06` crate feature.
+    #[cfg(feature = "raw-window-handle-06")]
+    pub fn window_handle(&self) -> WindowHandle {
+        WindowHandle { adapter: self.0.window_adapter() }
+    }
 }
 
 pub use crate::SharedString;

internal/core/window.rs

@@ -137,6 +137,22 @@ pub trait WindowAdapter {
     fn internal(&self, _: crate::InternalToken) -> Option<&dyn WindowAdapterInternal> {
         None
     }
+
+    /// Re-implement this to support exposing raw window handles (version 0.6).
+    #[cfg(feature = "raw-window-handle-06")]
+    fn window_handle_06(
+        &self,
+    ) -> Result<raw_window_handle_06::WindowHandle<'_>, raw_window_handle_06::HandleError> {
+        Err(raw_window_handle_06::HandleError::NotSupported)
+    }
+
+    /// Re-implement this to support exposing raw display handles (version 0.6).
+    #[cfg(feature = "raw-window-handle-06")]
+    fn display_handle_06(
+        &self,
+    ) -> Result<raw_window_handle_06::DisplayHandle<'_>, raw_window_handle_06::HandleError> {
+        Err(raw_window_handle_06::HandleError::NotSupported)
+    }
 }
 
 /// Implementation details behind [`WindowAdapter`], but since this

internal/interpreter/Cargo.toml

@@ -107,6 +107,12 @@ renderer-winit-software = ["renderer-software"]
 ## APIs to support screen readers and other assistive technologies.
 accessibility = ["i-slint-backend-selector/accessibility"]
 
+## Enable integration with [raw-window-handle](raw_window_handle_06) version 0.6. This provides a
+## [`Window::window_handle()`] function that returns a struct that implements
+## [HasWindowHandle](raw_window_handle_06::HasWindowHandle) and
+## [HasDisplayHandle](raw_window_handle_06::HasDisplayHandle) implementation.
+raw-window-handle-06 = ["dep:raw-window-handle-06", "i-slint-backend-selector/raw-window-handle-06"]
+
 ## Features used internally by Slint tooling that are not stable and come without
 ## any stability guarantees whatsoever.
 internal = []
@@ -126,6 +132,7 @@ once_cell = "1.5"
 thiserror = "1"
 document-features = { version = "0.2.0", optional = true }
 spin_on = { version = "0.1", optional = true }
+raw-window-handle-06 = { workspace = true, optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 i-slint-backend-winit = { workspace = true }
@@ -140,4 +147,4 @@ i-slint-backend-testing = { path = "../../internal/backends/testing" }
 spin_on = "0.1"
 
 [package.metadata.docs.rs]
-features = ["display-diagnostics", "document-features"]
+features = ["display-diagnostics", "document-features", "raw-window-handle-06"]