frontend: the advoware GUI

Signed-off-by: Ralf Zerres <ralf.zerres@networkx.de>

frontend/examples/todo/main.rs

@@ -0,0 +1,68 @@
+mod state;
+
+use self::state::{AppState, Event};
+
+use orbtk::prelude::*;
+
+widget! {
+    MainView<AppState> {
+	orientation: Orientation,
+	spacing: f64
+    }
+}
+
+impl Template for MainView {
+    fn template(mut self, id: Entity, ctx: &mut BuildContext) -> Self {
+	let entry = TextBox::create()
+	    .vertical_alignment(Alignment::End)
+	    .on_activate(move |ctxt, entity| {
+		ctxt.get_mut::<AppState>(id).send(Event::Create(entity));
+	    })
+	    .build(ctx);
+
+	let notes = Stack::create()
+	    .orientation(Orientation::Vertical)
+	    .spacing(4)
+	    .build(ctx);
+
+	self.state.notes = notes;
+
+	let scroll_viewer = ScrollViewer::create()
+	    .scroll_viewer_mode(("disabled", "auto"))
+	    .child(notes)
+	    .build(ctx);
+
+	self.name("main-view")
+	    .orientation(Orientation::Vertical)
+	    .margin(4)
+	    .child(
+		Container::create()
+		    .child(scroll_viewer)
+		    .child(
+			ScrollIndicator::create()
+			    .padding(2.0)
+			    .scroll_offset(scroll_viewer)
+			    .build(ctx),
+		    )
+		    .build(ctx)
+	    )
+	    .child(entry)
+    }
+
+    fn layout(&self) -> Box<dyn Layout> {
+	Box::new(StackLayout::new())
+    }
+}
+
+fn main() {
+    Application::new()
+	.window(|ctx| {
+	    Window::create()
+		.title("Orbital To Do")
+		.position((500.0, 500.0))
+		.size(400.0, 400.0)
+		.child(MainView::create().build(ctx))
+		.build(ctx)
+	})
+	.run();
+}