Main.java Source code

Introduction

Here is the source code for Main.java

Source

import javafx.application.Application;
import javafx.scene.Cursor;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Line;
import javafx.scene.shape.StrokeLineCap;
import javafx.stage.Stage;

public class Main extends Application {

    double orgSceneX, orgSceneY;

    private Circle createCircle(double x, double y, double r, Color color) {
        Circle circle = new Circle(x, y, r, color);

        circle.setCursor(Cursor.HAND);

        circle.setOnMousePressed((t) -> {
            orgSceneX = t.getSceneX();
            orgSceneY = t.getSceneY();

            Circle c = (Circle) (t.getSource());
            c.toFront();
        });
        circle.setOnMouseDragged((t) -> {
            double offsetX = t.getSceneX() - orgSceneX;
            double offsetY = t.getSceneY() - orgSceneY;

            Circle c = (Circle) (t.getSource());

            c.setCenterX(c.getCenterX() + offsetX);
            c.setCenterY(c.getCenterY() + offsetY);

            orgSceneX = t.getSceneX();
            orgSceneY = t.getSceneY();
        });
        return circle;
    }

    private Line connect(Circle c1, Circle c2) {
        Line line = new Line();

        line.startXProperty().bind(c1.centerXProperty());
        line.startYProperty().bind(c1.centerYProperty());

        line.endXProperty().bind(c2.centerXProperty());
        line.endYProperty().bind(c2.centerYProperty());

        line.setStrokeWidth(1);
        line.setStrokeLineCap(StrokeLineCap.BUTT);
        line.getStrokeDashArray().setAll(1.0, 4.0);

        return line;
    }

    @Override
    public void start(Stage primaryStage) {
        Group root = new Group();
        Scene scene = new Scene(root, 500, 260);

        // circles
        Circle redCircle = createCircle(100, 50, 30, Color.RED);
        Circle blueCircle = createCircle(20, 150, 20, Color.BLUE);
        Circle greenCircle = createCircle(40, 100, 40, Color.GREEN);

        Line line1 = connect(redCircle, blueCircle);
        Line line2 = connect(redCircle, greenCircle);
        Line line3 = connect(greenCircle, blueCircle);

        // add the circles
        root.getChildren().add(redCircle);
        root.getChildren().add(blueCircle);
        root.getChildren().add(greenCircle);

        // add the lines
        root.getChildren().add(line1);
        root.getChildren().add(line2);
        root.getChildren().add(line3);

        // bring the circles to the front of the lines
        redCircle.toFront();
        blueCircle.toFront();
        greenCircle.toFront();

        primaryStage.setScene(scene);
        primaryStage.show();
    }

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