UserInterface with TextMessages implemented.

js/ui/UserInterfaceElement.js

@@ -0,0 +1,38 @@
+import GeometryPoint from "../geometry/GeometryPoint.js";
+
+export default class UserInterfaceElement
+{
+    constructor()
+    {
+        this.position = new GeometryPoint(0, 0);
+        this.isVisible = true;
+    }
+
+    setPosition(x, y)
+    {
+        this.position.x = x;
+        this.position.y = y;
+    }
+
+    hide(timeoutMilliseconds = 0)
+    {
+        setTimeout(
+            () => {
+                this.isVisible = false
+            }, timeoutMilliseconds
+        );
+    }
+
+    show(timeoutMilliseconds = 0)
+    {
+        if (timeoutMilliseconds > 0) {
+            this.isVisible = false;
+        }
+
+        setTimeout(
+            () => {
+                this.isVisible = true;
+            }, timeoutMilliseconds
+        );
+    }
+}