Initializes WindowAdapter implementation (#1178)

gui/main_window.cpp

@@ -25,8 +25,7 @@
 #include <fcntl.h>
 #endif
 
-MainWindow::MainWindow() :
-    m_main(nullptr)
+MainWindow::MainWindow()
 {
     // File menu.
     auto fileMenu = menuBar()->addMenu("&File");
@@ -36,19 +35,11 @@ MainWindow::MainWindow() :
 
     // Help menu.
     auto helpMenu = menuBar()->addMenu("&Help");
-    auto aboutQt = new QAction("About &Qt", this);
     auto about = new QAction("&About Obliteration", this);
 
-    connect(aboutQt, &QAction::triggered, &QApplication::aboutQt);
     connect(about, &QAction::triggered, this, &MainWindow::aboutObliteration);
 
-    helpMenu->addAction(aboutQt);
     helpMenu->addAction(about);
-
-    // Central widget.
-    m_main = new QStackedWidget();
-
-    setCentralWidget(m_main);
 }
 
 MainWindow::~MainWindow()

gui/main_window.hpp

@@ -3,14 +3,10 @@
 #include <QList>
 #include <QMainWindow>
 
-class QStackedWidget;
-
 class MainWindow final : public QMainWindow {
 public:
     MainWindow();
     ~MainWindow() override;
 private slots:
     void aboutObliteration();
-private:
-    QStackedWidget *m_main;
 };

gui/src/rt/context.rs

@@ -0,0 +1,37 @@
+use std::cell::Cell;
+use std::mem::transmute;
+use std::ptr::null;
+use winit::event_loop::ActiveEventLoop;
+
+/// Execution context of the runtime.
+pub struct RuntimeContext<'a> {
+    el: &'a ActiveEventLoop,
+}
+
+impl<'a> RuntimeContext<'a> {
+    pub(super) fn new(el: &'a ActiveEventLoop) -> Self {
+        Self { el }
+    }
+
+    /// # Panics
+    /// If called from the other thread than main thread.
+    pub fn with<R>(f: impl FnOnce(&Self) -> R) -> R {
+        let cx = CONTEXT.get();
+        assert!(!cx.is_null());
+        unsafe { f(&*cx) }
+    }
+
+    pub fn event_loop(&self) -> &ActiveEventLoop {
+        self.el
+    }
+
+    pub(super) fn run(&self, f: impl FnOnce()) {
+        assert!(CONTEXT.replace(unsafe { transmute(self) }).is_null());
+        f();
+        CONTEXT.set(null());
+    }
+}
+
+thread_local! {
+    static CONTEXT: Cell<*const RuntimeContext<'static>> = Cell::new(null());
+}

gui/src/rt/mod.rs

@@ -1,3 +1,5 @@
+pub use self::context::*;
+
 use futures::executor::LocalPool;
 use futures::task::LocalSpawnExt;
 use std::future::Future;
@@ -8,6 +10,8 @@ use winit::event::WindowEvent;
 use winit::event_loop::{ActiveEventLoop, EventLoop};
 use winit::window::WindowId;
 
+mod context;
+
 pub fn block_on(main: impl Future<Output = ()> + 'static) -> Result<(), RuntimeError> {
     // Setup winit event loop.
     let mut el = EventLoop::<Event>::with_user_event();
@@ -17,7 +21,7 @@ pub fn block_on(main: impl Future<Output = ()> + 'static) -> Result<(), RuntimeE
     exe.spawner()
         .spawn_local(async move {
             main.await;
-            todo!()
+            RuntimeContext::with(|cx| cx.event_loop().exit());
         })
         .unwrap();
 
@@ -31,7 +35,9 @@ struct AsyncExecutor(LocalPool);
 
 impl ApplicationHandler<Event> for AsyncExecutor {
     fn resumed(&mut self, event_loop: &ActiveEventLoop) {
-        self.0.run_until_stalled();
+        let cx = RuntimeContext::new(event_loop);
+
+        cx.run(|| self.0.run_until_stalled());
     }
 
     fn window_event(

gui/src/ui/backend/mod.rs

@@ -1,7 +1,12 @@
+use self::window::Window;
+use crate::rt::RuntimeContext;
+use i_slint_renderer_skia::SkiaRenderer;
 use slint::platform::WindowAdapter;
-use slint::PlatformError;
+use slint::{PhysicalSize, PlatformError};
 use std::rc::Rc;
 
+mod window;
+
 /// Back-end for Slint to run on top of winit event loop.
 ///
 /// This back-end does not supports [`slint::run_event_loop()`].
@@ -15,6 +20,23 @@ impl SlintBackend {
 
 impl slint::platform::Platform for SlintBackend {
     fn create_window_adapter(&self) -> Result<Rc<dyn WindowAdapter>, PlatformError> {
-        todo!()
+        // Create winit window.
+        let attrs = winit::window::Window::default_attributes();
+        let win = match RuntimeContext::with(move |cx| cx.event_loop().create_window(attrs)) {
+            Ok(v) => Rc::new(v),
+            Err(e) => return Err(PlatformError::OtherError(Box::new(e))),
+        };
+
+        // Create WindowAdapter.
+        let size = win.inner_size();
+        let renderer = SkiaRenderer::new(
+            win.clone(),
+            win.clone(),
+            PhysicalSize::new(size.width, size.height),
+        )?;
+
+        Ok(Rc::<Window>::new_cyclic(move |weak| {
+            Window::new(win, slint::Window::new(weak.clone()), renderer)
+        }))
     }
 }

gui/src/ui/backend/window.rs

@@ -0,0 +1,41 @@
+use i_slint_renderer_skia::SkiaRenderer;
+use slint::platform::{Renderer, WindowAdapter};
+use slint::PhysicalSize;
+use std::rc::Rc;
+
+/// Implementation of [`WindowAdapter`].
+pub struct Window {
+    winit: Rc<winit::window::Window>,
+    slint: slint::Window,
+    renderer: SkiaRenderer,
+}
+
+impl Window {
+    pub fn new(
+        winit: Rc<winit::window::Window>,
+        slint: slint::Window,
+        renderer: SkiaRenderer,
+    ) -> Self {
+        Self {
+            winit,
+            slint,
+            renderer,
+        }
+    }
+}
+
+impl WindowAdapter for Window {
+    fn window(&self) -> &slint::Window {
+        &self.slint
+    }
+
+    fn size(&self) -> PhysicalSize {
+        let s = self.winit.inner_size();
+
+        PhysicalSize::new(s.width, s.height)
+    }
+
+    fn renderer(&self) -> &dyn Renderer {
+        &self.renderer
+    }
+}