Simplify signature of Component::run

We don't need to pass the root item anymore since ComponentVTable
has now get_item_ref.

api/sixtyfps-cpp/include/sixtyfps.h

@@ -84,7 +84,7 @@ struct ComponentWindow
     void run(const Component *c) const
     {
         sixtyfps_component_window_run(
-                &inner, vtable::VRefMut<ComponentVTable> { &Component::component_type, const_cast<Component *>(c) }, c->root_item());
+                &inner, vtable::VRefMut<ComponentVTable> { &Component::component_type, const_cast<Component *>(c) });
     }
 
     float scale_factor() const { return sixtyfps_component_window_get_scale_factor(&inner); }

api/sixtyfps-node/native/lib.rs

@@ -329,7 +329,7 @@ declare_types! {
             let component = cx.borrow(&mut this, |x| x.0.clone());
             let component = component.ok_or(()).or_else(|()| cx.throw_error("Invalid type"))?;
             run_scoped(&mut cx,this.downcast().unwrap(), || {
-                component.window().run(component.borrow(), component.borrow_instance().root_item());
+                component.window().run(component.borrow());
                 Ok(())
             })?;
             Ok(JsUndefined::new().as_value(&mut cx))

api/sixtyfps-wasm-interpreter/src/lib.rs

@@ -127,6 +127,6 @@ impl WrappedCompiledComp {
     #[wasm_bindgen]
     pub fn run(&self, canvas_id: String) {
         let component = self.0.clone().create(canvas_id);
-        component.window().run(component.borrow(), component.borrow_instance().root_item());
+        component.window().run(component.borrow());
     }
 }

sixtyfps_compiler/generator/rust.rs

@@ -572,8 +572,6 @@ fn generate_component(
         maybe_window_field_decl = Some(quote!(pub window: sixtyfps::re_exports::ComponentWindow));
         maybe_window_field_init = Some(quote!(window: sixtyfps::create_window()));
 
-        let root_elem = component.root_element.borrow();
-        let root_item_name = format_ident!("{}", root_elem.id);
         visibility = Some(quote!(pub));
 
         has_window_impl = Some(quote!(
@@ -585,8 +583,7 @@ fn generate_component(
             impl sixtyfps::Component for #component_id {
                 fn run(self: ::core::pin::Pin<&Self>) {
                     use sixtyfps::re_exports::*;
-                    let root_item = Self::FIELD_OFFSETS.#root_item_name.apply_pin(self);
+                    self.as_ref().window.run(VRef::new_pin(self.as_ref()));
-                    self.as_ref().window.run(VRef::new_pin(self.as_ref()), VRef::new_pin(root_item));
                 }
             }
         ))

sixtyfps_runtime/corelib/eventloop.rs

@@ -14,7 +14,6 @@ LICENSE END */
     aspects of windows on the screen.
 */
 use crate::component::ComponentVTable;
-use crate::items::ItemRef;
 use std::cell::RefCell;
 use std::{
     convert::TryInto,
@@ -70,11 +69,15 @@ pub trait GenericWindow {
     /// Arguments:
     /// * `event_loop`: The event loop used to drive further event handling for this window
     ///   as it will receive events.
-    /// * `root_item`: The root item of the scene. If the item is a [`crate::items::Window`], then
+    /// * `component`: The component that holds the root item of the scene. If the item is a [`crate::items::Window`], then
     ///   the `width` and `height` properties are read and the values are passed to the windowing system as request
     ///   for the initial size of the window. Then bindings are installed on these properties to keep them up-to-date
     ///   with the size as it may be changed by the user or the windowing system in general.
-    fn map_window(self: Rc<Self>, event_loop: &EventLoop, root_item: Pin<ItemRef>);
+    fn map_window(
+        self: Rc<Self>,
+        event_loop: &EventLoop,
+        component: core::pin::Pin<crate::component::ComponentRef>,
+    );
     /// Removes the window from the screen. The window is not destroyed though, it can be show (mapped) again later
     /// by calling [`GenericWindow::map_window`].
     fn unmap_window(self: Rc<Self>);
@@ -140,10 +143,10 @@ impl ComponentWindow {
         Self(window_impl)
     }
     /// Spins an event loop and renders the items of the provided component in this window.
-    pub fn run(&self, component: Pin<VRef<ComponentVTable>>, root_item: Pin<ItemRef>) {
+    pub fn run(&self, component: Pin<VRef<ComponentVTable>>) {
         let event_loop = crate::eventloop::EventLoop::new();
 
-        self.0.clone().map_window(&event_loop, root_item);
+        self.0.clone().map_window(&event_loop, component);
 
         event_loop.run(component);
 
@@ -581,10 +584,9 @@ pub mod ffi {
     pub unsafe extern "C" fn sixtyfps_component_window_run(
         handle: *const ComponentWindowOpaque,
         component: Pin<VRef<ComponentVTable>>,
-        root_item: Pin<VRef<ItemVTable>>,
     ) {
         let window = &*(handle as *const ComponentWindow);
-        window.run(component, root_item);
+        window.run(component);
     }
 
     /// Returns the window scale factor.

sixtyfps_runtime/corelib/graphics.rs

@@ -639,7 +639,7 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
     fn map_window(
         self: Rc<Self>,
         event_loop: &crate::eventloop::EventLoop,
-        root_item: Pin<ItemRef>,
+        component: core::pin::Pin<crate::component::ComponentRef>,
     ) {
         if matches!(&*self.map_state.borrow(), GraphicsWindowBackendState::Mapped(..)) {
             return;
@@ -670,6 +670,8 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
 
                 let mut new_size = existing_size;
 
+                let root_item = component.as_ref().get_item_ref(0);
+
                 if let Some(window_item) = ItemRef::downcast_pin(root_item) {
                     let width =
                         crate::items::Window::FIELD_OFFSETS.width.apply_pin(window_item).get();

tools/viewer/main.rs

@@ -44,6 +44,6 @@ fn main() -> std::io::Result<()> {
     };
 
     let component = c.create();
-    component.window().run(component.borrow(), component.borrow_instance().root_item());
+    component.window().run(component.borrow());
     Ok(())
 }