JavaFX - Sierpinski Triangle

Controller.java

package sample;

import javafx.application.Platform;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;

import java.net.URL;
import java.time.LocalTime;
import java.util.ResourceBundle;

public class Controller implements Initializable {

    @FXML
    private Label time;

    @FXML
    private TextField textInput;

    @FXML
    private BorderPane borderPane;

    SierpinskiTrianglePane trianglePane = new SierpinskiTrianglePane();



    @FXML
    private Label timeLabel;


    @Override
    public void initialize(URL url, ResourceBundle resourceBundle) {
        borderPane.setCenter(trianglePane);

        trianglePane.widthProperty().addListener(ov -> trianglePane.paint());
        trianglePane.heightProperty().addListener(ov -> trianglePane.paint());

        trianglePane.paint();

        textInput.setOnAction(
                e -> trianglePane.setOrder(Integer.parseInt(textInput.getText())));

        //timeHandler = new TimeHandler(time);


        Runnable timeHandler = new Runnable() {
            @Override
            public void run() {
                while (true) {
                    try {
                        Thread.sleep(1000);
                        Platform.runLater(new Runnable() {
                            @Override
                            public void run() {
                                timeLabel.setText(String.valueOf(LocalTime.now()));
                            }
                        });
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };

        Thread thread = new Thread(timeHandler);
        thread.start();

    }
}

Main.java

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root));
        primaryStage.show();
    }


    public static void main(String[] args) {
        launch(args);
    }
}

sample.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.BorderPane?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" style="-fx-background-color: #EAF4D3;" xmlns="http://javafx.com/javafx/15.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
   <children>
      <TextField fx:id="textInput" layoutX="226.0" layoutY="332.0" />
      <BorderPane fx:id="borderPane" layoutX="150.0" layoutY="33.0" prefHeight="260.0" prefWidth="301.0" />
      <Label fx:id="time" layoutX="64.0" layoutY="192.0" text="Label" />
   </children>
</AnchorPane>

SierpinskiTrianglePane.java

package sample;

import javafx.geometry.Point2D;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;

public class SierpinskiTrianglePane extends Pane {
    private int order = 0;

    public void setOrder(int order) {
        this.order = order;
        paint();
    }

    SierpinskiTrianglePane() {
    }

    protected void paint() {
        // Select three points in proportion to the pane size
        Point2D p1 = new Point2D(getWidth() / 2, 10);
        Point2D p2 = new Point2D(10, getHeight() - 10);
        Point2D p3 = new Point2D(getWidth() - 10, getHeight() - 10);

        this.getChildren().clear(); // Clear the pane before redisplay

        displayTriangles(order, p1, p2, p3);
    }

    private void displayTriangles(int order, Point2D p1,
                                  Point2D p2, Point2D p3) {
        if (order == 0) {
            // Draw a triangle to connect three points
                Polygon triangle = new Polygon();
            triangle.getPoints().addAll(p1.getX(), p1.getY(), p2.getX(),
                    p2.getY(), p3.getX(), p3.getY());
            triangle.setStroke(Color.BLACK);
            triangle.setFill(Color.WHITE);

            this.getChildren().add(triangle);
        } else {
            // Get the midpoint on each edge in the triangle
            Point2D p12 = p1.midpoint(p2);
            Point2D p23 = p2.midpoint(p3);
            Point2D p31 = p3.midpoint(p1);

            // Recursively display three triangles
            displayTriangles(order - 1, p1, p12, p31);
            displayTriangles(order - 1, p12, p2, p23);
            displayTriangles(order - 1, p31, p23, p3);
        }
    }
}