Updatable Polygon with Statistics

UpdatePolygonApp.java

// Updatable Polygon Homework V2
// Antonio C. Silvestri
// CSC-112 Intermediate Java Programming
// 04/03/2018

package polygon;

import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.geometry.Orientation;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.Separator;
import javafx.scene.control.TextField;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.layout.BorderPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;
import javafx.stage.Stage;

public class UpdatePolygonApp extends Application {
	@Override
	public void start(Stage primaryStage) {
		Scene scene = new Scene(new AppGUI(), 575, 575);
		primaryStage.setTitle("Updatable Polygon By A.C. Silvestri");
		primaryStage.setScene(scene);
		primaryStage.show();
	}

	/**
	 * The main method is only needed for the IDE with limited JavaFX support. Not
	 * needed for running from the command line.
	 */
	public static void main(String[] args) {
		launch(args);
	}
}

class AppGUI extends BorderPane {
	public AppGUI() {
		UpdatablePolygonPane updatePolyPane = new UpdatablePolygonPane();
		StatisticsPane statsPane = new StatisticsPane();
        SizeControls hBox = new SizeControls(updatePolyPane, statsPane);
		
		this.setCenter(updatePolyPane);
		this.setRight(statsPane);
		this.setBottom(hBox);		
	}
}


class SizeControls extends HBox {
	public SizeControls(UpdatablePolygonPane updatePolyPane,
			            StatisticsPane statsPane) {
		this.setSpacing(10);
		this.setAlignment(Pos.CENTER);
		Button btEnlarge = new Button("+");
		Button btShrink = new Button("-");
		this.getChildren().add(btEnlarge);
		this.getChildren().add(btShrink);
		
		btEnlarge.setOnAction(x -> {
			updatePolyPane.enlarge();
			statsPane.updateStats(updatePolyPane);
		});
		btShrink.setOnAction(x -> {
			updatePolyPane.shrink();
			statsPane.updateStats(updatePolyPane);
		});
		statsPane.updateStats(updatePolyPane);
	}
	
}


class UpdatablePolygonPane extends StackPane {
	private int sides = 4;
	private double radius;

	public int getSides() {
		return this.sides;
	}
	
	public double getRadius() {
		return this.radius;
	}
	
	public UpdatablePolygonPane() {
		this.radius = 200;
		this.paint();
	}

	public void shrink() {
		if (this.sides > 2)
			this.sides--;
		this.paint();
	}

	public void enlarge() {
		this.sides++;
		this.paint();
	}

	private void paint() {
		this.getChildren().clear();

		double centerX = this.getWidth() / 2;
		double centerY = this.getHeight() / 2;
		Polygon poly = new Polygon();
		poly.setFill(Color.WHITE);
		poly.setStroke(Color.BLACK);
		ObservableList<Double> list = poly.getPoints();

		// Add points to the polygon list
		for (int i = 0; i < this.sides; i++) {
			list.add(centerX + this.radius * Math.cos(2 * i * Math.PI / this.sides));
			list.add(centerY - this.radius * Math.sin(2 * i * Math.PI / this.sides));
		}

		this.getChildren().add(poly);
	}

}

class StatisticsPane extends HBox {
	private TextField txtNoOfSides;
	private TextField txtPolyArea;
	private TextField txtCircleArea;
	private TextField txtAreaDelta;

	public StatisticsPane() {
		this.setPrefWidth(150);

		VBox vbox = new VBox(10);
		vbox.setPadding(new Insets(0, 10, 0, 10));
		vbox.setAlignment(Pos.CENTER);

		VBox vboxNoOfSidesGroup = new VBox(1);
		txtNoOfSides = new TextField();
		txtNoOfSides.setEditable(false);
		vboxNoOfSidesGroup.getChildren()
		.addAll(new Label("No Of Sides"), txtNoOfSides);

		VBox vboxPolyAreaGroup = new VBox(1);
		txtPolyArea = new TextField();
		txtPolyArea.setEditable(false);
		vboxPolyAreaGroup.getChildren()
		.addAll(new Label("PolyArea"), txtPolyArea);

		VBox vboxCircleAreaGroup = new VBox(1);
		txtCircleArea = new TextField();
		txtCircleArea.setEditable(false);
		vboxCircleAreaGroup.getChildren()
		.addAll(new Label("Circle Area"), txtCircleArea);

		VBox vBoxAreaDeltaGroup = new VBox(1);
		txtAreaDelta = new TextField();
		txtAreaDelta.setEditable(false);
		vBoxAreaDeltaGroup.getChildren()
		.addAll(new Label("Area Delta"), txtAreaDelta);

		vbox.getChildren().addAll(vboxNoOfSidesGroup, vboxPolyAreaGroup, vboxCircleAreaGroup, vBoxAreaDeltaGroup);
		this.getChildren().addAll(
				new Separator(Orientation.VERTICAL), vbox);
	}
	
	public void updateStats(UpdatablePolygonPane upp) {
		int sides = upp.getSides();
		double radius = upp.getRadius();
		
		this.txtNoOfSides.setText(Integer.toString(sides));
		
		double polyArea = sides * radius * radius * Math.sin(2 * Math.PI / sides) / 2.0;
		this.txtPolyArea.setText(String.format("%.5f", polyArea));
		
		double circleArea = Math.PI * radius * radius;
		this.txtCircleArea.setText(String.format("%.5f", circleArea));
		
		double delta = circleArea - polyArea;
		this.txtAreaDelta.setText(String.format("%.5f", delta));
	}

}