Use the color property of the window as a background

CHANGELOG.md

@@ -9,6 +9,7 @@ All notable changes to this project will be documented in this file.
 
 ### Added
  - title property to the Window element
+ - color property to the Window element
 
 
 ## [0.0.4] - 2020-12-04

examples/gallery/gallery.60

@@ -13,11 +13,7 @@ App := Window {
     width: 500px;
     height: 550px;
     title: "SixtyFPS Gallery";
-    Rectangle {
-        color: #ecedeb;
-        width: parent.width;
-        height: parent.height;
-    }
+    color: #ecedeb;
 
     VerticalLayout {
         padding: 20px;

sixtyfps_runtime/corelib/graphics.rs

@@ -722,11 +722,14 @@ impl<Backend: GraphicsBackend> crate::eventloop::GenericWindow for GraphicsWindo
         let window = map_state.as_mapped();
         let mut backend = window.backend.borrow_mut();
         let size = backend.window().inner_size();
-        let mut frame = backend.new_frame(
-            size.width,
-            size.height,
-            &RgbaColor { red: 255 as u8, green: 255, blue: 255, alpha: 255 }.into(),
-        );
+        let root_item = component.as_ref().get_item_ref(0);
+        let background_color = if let Some(window_item) = ItemRef::downcast_pin(root_item) {
+            crate::items::Window::FIELD_OFFSETS.color.apply_pin(window_item).get()
+        } else {
+            RgbaColor { red: 255 as u8, green: 255, blue: 255, alpha: 255 }.into()
+        };
+
+        let mut frame = backend.new_frame(size.width, size.height, &background_color);
         crate::item_rendering::render_component_items(
             &component_rc,
             &mut frame,