Implements RuntimeWindow::redraw (#1184)

gui/src/rt/context.rs

@@ -59,12 +59,14 @@ impl<'a> RuntimeContext<'a> {
 
     /// # Panics
     /// If this call has been nested.
-    pub(super) fn run(&mut self, f: impl FnOnce()) {
+    pub(super) fn run<R>(&mut self, f: impl FnOnce() -> R) -> R {
         assert!(CONTEXT.get().is_null());
 
         CONTEXT.set(unsafe { transmute(self) });
-        f();
+        let r = f();
         CONTEXT.set(null_mut());
+
+        r
     }
 }
 

gui/src/rt/mod.rs

@@ -101,6 +101,29 @@ impl Runtime {
 
         true
     }
+
+    fn redraw(&mut self, el: &ActiveEventLoop, win: WindowId) {
+        // Get target window.
+        let win = match self.windows.get(&win).unwrap().upgrade() {
+            Some(v) => v,
+            None => return,
+        };
+
+        // Setup context.
+        let mut cx = RuntimeContext {
+            el,
+            windows: &mut self.windows,
+            on_close: &mut self.on_close,
+        };
+
+        // Redraw.
+        let e = match cx.run(move || win.redraw()) {
+            Ok(_) => return,
+            Err(e) => e,
+        };
+
+        todo!()
+    }
 }
 
 impl ApplicationHandler<Event> for Runtime {
@@ -127,7 +150,7 @@ impl ApplicationHandler<Event> for Runtime {
         match event {
             WindowEvent::CloseRequested => self.on_close.raise(window_id, ()),
             WindowEvent::Destroyed => drop(self.windows.remove(&window_id)),
-            WindowEvent::RedrawRequested => todo!(),
+            WindowEvent::RedrawRequested => self.redraw(event_loop, window_id),
             _ => {}
         }
     }

gui/src/rt/window.rs

@@ -1,2 +1,6 @@
+use std::error::Error;
+
 /// Encapsulates winit window with application-specific logic.
-pub trait RuntimeWindow {}
+pub trait RuntimeWindow {
+    fn redraw(&self) -> Result<(), Box<dyn Error>>;
+}

gui/src/ui/backend/window.rs

@@ -6,6 +6,7 @@ use slint::platform::{Renderer, WindowAdapter};
 use slint::{PhysicalSize, PlatformError};
 use std::any::Any;
 use std::cell::Cell;
+use std::error::Error;
 use std::rc::Rc;
 use winit::window::WindowId;
 
@@ -36,7 +37,17 @@ impl Window {
     }
 }
 
-impl RuntimeWindow for Window {}
+impl RuntimeWindow for Window {
+    fn redraw(&self) -> Result<(), Box<dyn Error>> {
+        // Wayland will show the window on the first render so we need to check visibility flag
+        // here.
+        if self.visible.get().is_some_and(|v| v) {
+            self.renderer.render()?;
+        }
+
+        Ok(())
+    }
+}
 
 impl WindowAdapter for Window {
     fn window(&self) -> &slint::Window {