added LayerdRootElement

src/lib/ui/elements/LayerdRootElement.hx

@@ -0,0 +1,29 @@
+package lib.ui.elements;
+
+class LayerdRootElement implements UIElement {
+	private var children:Array<{element:UIElement, offset:Pos}>;
+	private final eventManager:UIEventManager = new UIEventManager();
+
+	public function new(?children:Array<{element:UIElement, offset:Pos}>) {
+		this.children = children == null ? [] : children;
+	}
+
+	public function setChildren(children:Array<{element:UIElement, offset:Pos}>) {
+		this.children = children;
+	}
+
+	public function getEventHandlers():UIEvents {
+		return eventManager.getEventHandlers();
+	}
+
+	public function render(bounds:Pos):Canvas {
+		// TODO: add event handle
+		var stack = new CanvasStack();
+
+		for (child in this.children) {
+			stack.addLayer(child.element.render(bounds), child.offset);
+		}
+
+		return stack.compress();
+	}
+}