JAVAFX: Draw polygon by mouse click and re-size shape by anchor points

	package com.jay.shape.drawtriangle;
	import java.util.ArrayList;
	import java.util.List;
	import javafx.application.Application;
	import javafx.beans.property.DoubleProperty;
	import javafx.beans.property.SimpleDoubleProperty;
	import javafx.beans.value.ChangeListener;
	import javafx.beans.value.ObservableValue;
	import javafx.collections.FXCollections;
	import javafx.collections.ObservableList;
	import javafx.event.EventHandler;
	import javafx.scene.Group;
	import javafx.scene.Scene;
	import javafx.scene.input.MouseEvent;
	import javafx.scene.layout.AnchorPane;
	import javafx.scene.paint.Color;
	import javafx.scene.shape.Arc;
	import javafx.scene.shape.ArcType;
	import javafx.scene.shape.Circle;
	import javafx.scene.shape.Polygon;
	import javafx.scene.shape.StrokeLineCap;
	import javafx.scene.shape.StrokeType;
	import javafx.stage.Stage;
	/**
	*
	* @author jay.thakkar
	*/
	public class DrawTriangle extends Application {
	Group root;
	@Override
	public void start(Stage primaryStage) {
	AnchorPane anchorPane = new AnchorPane();
	root = new Group();
	anchorPane.setOnMouseDragged(mouseHandler);
	anchorPane.setOnMousePressed(mouseHandler);
	anchorPane.setOnMouseReleased(mouseHandler);
	//root.getChildren().add(triangle);
	// root.getChildren().addAll(createControlAnchorsFor(triangle.getPoints()));
	anchorPane.getChildren().add(root);
	primaryStage.setTitle("Hello World!");
	primaryStage.setScene(
	new Scene(
	anchorPane,
	400, 400, Color.ALICEBLUE));
	primaryStage.show();
	}
	public static void main(String[] args) {
	launch(args);
	}
	double x[] = new double[3];
	double y[] = new double[3];
	int count = 0;
	boolean drawShape = true;
	Polygon triangle;
	List<Double> values = new ArrayList<Double>();
	EventHandler<MouseEvent> mouseHandler = new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	if (mouseEvent.getEventType() == MouseEvent.MOUSE_PRESSED) {
	if (drawShape) {
	x[count] = mouseEvent.getX();
	y[count] = mouseEvent.getY();
	System.out.println("X:" + mouseEvent.getX());
	System.out.println("Y:" + mouseEvent.getY());
	}
	} else if (mouseEvent.getEventType() == MouseEvent.MOUSE_RELEASED) {
	if (drawShape) {
	triangle = new Polygon();
	values.add(x[count]);
	values.add(y[count]);
	count++;
	triangle.getPoints().addAll(values);
	// triangle.getPoints().setAll(
	// x[0], y[0],
	// x[1], y[1],
	// x[2], y[2]);
	triangle.setStroke(Color.FORESTGREEN);
	triangle.setStrokeWidth(4);
	triangle.setStrokeLineCap(StrokeLineCap.ROUND);
	triangle.setFill(Color.CORNSILK.deriveColor(0, 1.2, 1, 0.6));
	root.getChildren().clear();
	root.getChildren().add(triangle);
	root.getChildren().addAll(createControlAnchorsFor(triangle.getPoints()));
	if (count == 3) {
	drawShape = false;
	count = 0;
	calculateAngle();
	//root.getChildren().addAll(createDegreeAngleFor(triangle.getPoints()));
	}
	}
	}
	}
	};
	double getLineDistance(double x1, double y1, double x2, double y2) {
	double s1 = Math.pow((x2 - x1), 2);
	double s2 = Math.pow((y2 - y1), 2);
	double s3 = Math.sqrt(s1 + s2);
	return s3;
	}
	int angels[] = new int[3];
	public void calculateAngle() {
	double x1 = triangle.getPoints().get(0);
	double y1 = triangle.getPoints().get(1);
	double x2 = triangle.getPoints().get(2);
	double y2 = triangle.getPoints().get(3);
	double x3 = triangle.getPoints().get(4);
	double y3 = triangle.getPoints().get(5);
	double a = getLineDistance(x1, y1, x2, y2);
	double b = getLineDistance(x2, y2, x3, y3);
	double c = getLineDistance(x3, y3, x1, y1);
	double pi = Math.PI;
	double angleA = Math.acos((b * b + c * c - a * a) / (2.0 * b * c)) * (180.0 / pi);
	double angleB = Math.acos((a * a + c * c - b * b) / (2.0 * a * c)) * (180.0 / pi);
	double angleC = (180.0 - angleA - angleB);
	System.out.println("=================================");
	System.out.println("angleA:" + angleA);
	System.out.println("angleB:" + angleB);
	System.out.println("angleC:" + angleC);
	angels[0] = (int) Math.round(angleA);
	angels[2] = (int) Math.round(angleB);
	angels[1] = (int) Math.round(angleC);
	}
	// a draggable anchor displayed around a point.
	class Anchor extends Circle {
	Anchor(Color color, DoubleProperty x, DoubleProperty y) {
	super(x.get(), y.get(), 10);
	setFill(color.deriveColor(1, 1, 1, 0.5));
	setStroke(color);
	setStrokeWidth(2);
	setStrokeType(StrokeType.OUTSIDE);
	x.bind(centerXProperty());
	y.bind(centerYProperty());
	enableDrag();
	}
	// make a node movable by dragging it around with the mouse.
	private void enableDrag() {
	final Delta dragDelta = new Delta();
	setOnMousePressed(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	// record a delta distance for the drag and drop operation.
	dragDelta.x = getCenterX() - mouseEvent.getX();
	dragDelta.y = getCenterY() - mouseEvent.getY();
	getScene().setCursor(javafx.scene.Cursor.MOVE);
	}
	});
	setOnMouseReleased(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	getScene().setCursor(javafx.scene.Cursor.HAND);
	System.out.println("values:" + values);
	}
	});
	setOnMouseDragged(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	double newX = mouseEvent.getX() + dragDelta.x;
	if (newX > 0 && newX < getScene().getWidth()) {
	setCenterX(newX);
	}
	double newY = mouseEvent.getY() + dragDelta.y;
	if (newY > 0 && newY < getScene().getHeight()) {
	setCenterY(newY);
	}
	calculateAngle();
	}
	});
	setOnMouseEntered(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	if (!mouseEvent.isPrimaryButtonDown()) {
	getScene().setCursor(javafx.scene.Cursor.HAND);
	}
	}
	});
	setOnMouseExited(new EventHandler<MouseEvent>() {
	@Override
	public void handle(MouseEvent mouseEvent) {
	if (!mouseEvent.isPrimaryButtonDown()) {
	getScene().setCursor(javafx.scene.Cursor.DEFAULT);
	}
	}
	});
	}
	// records relative x and y co-ordinates.
	private class Delta {
	double x, y;
	}
	}
	// @return a list of anchors which can be dragged around to modify points in the format [x1, y1, x2, y2...]
	private ObservableList<Anchor> createControlAnchorsFor(final ObservableList<Double> points) {
	ObservableList<Anchor> anchors = FXCollections.observableArrayList();
	for (int i = 0; i < points.size(); i += 2) {
	final int idx = i;
	DoubleProperty xProperty = new SimpleDoubleProperty(points.get(i));
	DoubleProperty yProperty = new SimpleDoubleProperty(points.get(i + 1));
	xProperty.addListener(new ChangeListener<Number>() {
	@Override
	public void changed(ObservableValue<? extends Number> ov, Number oldX, Number x) {
	points.set(idx, (double) x);
	}
	});
	yProperty.addListener(new ChangeListener<Number>() {
	@Override
	public void changed(ObservableValue<? extends Number> ov, Number oldY, Number y) {
	points.set(idx + 1, (double) y);
	}
	});
	anchors.add(new Anchor(Color.GOLD, xProperty, yProperty));
	}
	return anchors;
	}
	private ObservableList<DegreeAngel> createDegreeAngleFor(final ObservableList<Double> points) {
	ObservableList<DegreeAngel> degreeAngels = FXCollections.observableArrayList();
	int j = 0;
	for (int i = 0; i < points.size(); i += 2) {
	final int idx = i;
	DoubleProperty xProperty = new SimpleDoubleProperty(points.get(i));
	DoubleProperty yProperty = new SimpleDoubleProperty(points.get(i + 1));
	xProperty.addListener(new ChangeListener<Number>() {
	@Override
	public void changed(ObservableValue<? extends Number> ov, Number oldX, Number x) {
	points.set(idx, (double) x);
	}
	});
	yProperty.addListener(new ChangeListener<Number>() {
	@Override
	public void changed(ObservableValue<? extends Number> ov, Number oldY, Number y) {
	points.set(idx + 1, (double) y);
	}
	});
	degreeAngels.add(new DegreeAngel(Color.BLACK, xProperty, yProperty, angels[j]));
	j++;
	}
	return degreeAngels;
	}
	class DegreeAngel extends Arc {
	public DegreeAngel(Color color, DoubleProperty x, DoubleProperty y, int angle) {
	super(x.get(), y.get(), 25.0f, 25.0f, 0, angle);
	setFill(color.deriveColor(1, 1, 1, 0.5));
	setStroke(color);
	setStrokeWidth(1);
	setStrokeType(StrokeType.OUTSIDE);
	setType(ArcType.ROUND);
	x.bind(centerXProperty());
	y.bind(centerYProperty());
	}
	}
	}

view raw DrawTriangle.java hosted with ❤ by GitHub