Flyout effect with JavaFX

FlyoutEffect.java

package org.sandbox.jfx;

import javafx.animation.Interpolator;
import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.embed.swing.JFXPanel;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.scene.shape.Rectangle;
import javafx.util.Duration;

import javax.swing.JFrame;
import java.awt.Dimension;
import java.awt.Toolkit;

public class FlyoutEffect extends JFrame {

    public FlyoutEffect() {
        super("Flyout effect");
        setSize(800, 600);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        centerWindow();
        initUI();
    }

    private void centerWindow() {
        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        setLocation(dim.width / 2 - getSize().width / 2, dim.height / 2 - getSize().height / 2);
    }

    private void initUI() {
        var jfxPanel = new JFXPanel();
        var root = new BorderPane();
        root.setPrefSize(800, 600);

        var top = new HBox();
        top.setAlignment(Pos.CENTER);
        top.setStyle("-fx-border-color: red; -fx-border-width: 1px; -fx-padding: 10px;");
        top.getChildren().add(new Label("Top"));
        root.setTop(top);

        var left = new VBox();
        left.setAlignment(Pos.CENTER);
        left.setStyle("-fx-border-color: green; -fx-border-width: 1px; -fx-padding: 10px;");
        left.getChildren().add(new Label("Left"));
        root.setLeft(left);


        var center = new Pane();
        center.setMaxSize(400, 150);
        center.setStyle("-fx-border-color: black; -fx-border-width: 1px;");
        center.setClip(new Rectangle(400, 150));

        var flyout = new HBox();
        flyout.setMaxSize(150, 150);
        flyout.setPrefSize(150, 150);
        flyout.setStyle("-fx-background-color: lightblue");
        flyout.setLayoutX(550);
        flyout.setLayoutY(0);
        center.getChildren().add(flyout);

        center.setOnMouseEntered(e -> {
            var kv = new KeyValue(flyout.layoutXProperty(), 250, Interpolator.EASE_BOTH);
            var kf = new KeyFrame(Duration.seconds(0.3), kv);
            var timeline = new Timeline(kf);
            timeline.play();
        });

        center.setOnMouseExited(e -> {
            var kv = new KeyValue(flyout.layoutXProperty(), 550, Interpolator.EASE_BOTH);
            var kf = new KeyFrame(Duration.seconds(0.3), kv);
            var timeline = new Timeline(kf);
            timeline.play();
        });

        var button = new Button("Click me!");
        button.setOnAction(e -> System.out.println("Clicked!"));
        flyout.getChildren().add(button);
        flyout.setAlignment(Pos.CENTER);

        root.setCenter(center);

        var scene = new Scene(root);
        jfxPanel.setScene(scene);
        getContentPane().add(jfxPanel);
    }


    public static void main(String[] args) {
        var app = new FlyoutEffect();
        app.setVisible(true);
    }
}