Sierpinksi Triangle using Java brainstorming

programming
1

I am looking at this blog post and trying to translate that code to an object oriented programming style code. Could you help me brainstorm a bit?

I am thinking about creating a class named Sierpinski and other class named DisplaySierpinski.

Where do I put the codes?

2 
package com.example.demo;

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;

    SierpinskiTrianglePane() {

    }

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

    protected void paint() {
        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();
        displayTriangles(order, p1, p2, p3);

    }

    public void displayTriangles(int order, Point2D p1, Point2D p2, Point2D p3) {

        if (order == 0) {
            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 {
            Point2D p12 = p1.midpoint(p2);
            Point2D p23 = p2.midpoint(p3);
            Point2D p31 = p3.midpoint(p1);

            displayTriangles(order - 1, p1, p12, p31);
            displayTriangles(order - 1, p12, p2, p23);
            displayTriangles(order - 1, p31, p23, p3);
        }
    }

}

And

package com.example.demo;

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class Sierpinski extends Application {
    @Override
    public void start(Stage primaryStage) {
        SierpinskiTrianglePane trianglePane = new SierpinskiTrianglePane();
        TextField tfOrder = new TextField();
        tfOrder.setOnAction(e -> trianglePane.setOrder(Integer.parseInt(tfOrder.getText())));
        tfOrder.setPrefColumnCount(4);
        tfOrder.setAlignment(Pos.BOTTOM_RIGHT);

        HBox hBox = new HBox(10);
        hBox.getChildren().addAll(new Label("Enter an order"), tfOrder);
        hBox.setAlignment(Pos.CENTER);

        BorderPane borderPane = new BorderPane();
        borderPane.setCenter(trianglePane);
        borderPane.setBottom(hBox);

        Scene scene = new Scene(borderPane, 200, 210);
        primaryStage.setTitle("SierpinskiTriangle");
        primaryStage.setScene(scene);
        primaryStage.show();

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

I got the solution from Daniel Liang's java textbook. I understand the solution, but I would not be able to create it on my own.
3

Before you try to make it OOP style, you should define what parts you would like to reuse and what parts will be used just once. For example, you may always have just a single scene.

You may have a lot of triangles, so your triangle can be a class with properties for starting position and number of recursions. That is just an example, and you can have many variations!

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