Explain the Union operation on 2D shapes in JavaFX

This operation takes two or more shapes as inputs and returns the area occupied by them combined as shown below.

The union() (static) method of the javafx.scene.shape.Shape class accepts two Shape objects and returns the result of the union operation of the given objects.

Example

import javafx.application.Application; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.paint.Color; import javafx.stage.Stage; import javafx.scene.shape.Circle; import javafx.scene.shape.Shape; public class JavaFXUnionExample extends Application {    public void start(Stage stage) {       //Drawing circle1       Circle circle1 = new Circle();       circle1.setCenterX(230.0f);       circle1.setCenterY(100.0f);       circle1.setRadius(75.0f);       circle1.setFill(Color.DARKRED);       //Drawing Circle2       Circle circle2 = new Circle();       circle2.setCenterX(280.0f);       circle2.setCenterY(170.0f);       circle2.setRadius(75.0f);       circle2.setFill(Color.DARKRED);       //Drawing Circle3       Circle circle3 = new Circle();       circle3.setCenterX(330.0f);       circle3.setCenterY(100.0f);       circle3.setRadius(75.0f);       circle3.setFill(Color.DARKRED);       //Union operation       Shape union = Shape.union(circle1, circle2);       union = Shape.union(union, circle3);       union.setFill(Color.RED);       //Setting the stage       Group root = new Group(circle1, circle2, circle3, union);       Scene scene = new Scene(root, 595, 300);       stage.setTitle("Union Operation");       stage.setScene(scene);       stage.show();    }    public static void main(String args[]){       launch(args);    } }

Output