2D Shapes(Objects) - Union Operation

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

You can perform union operation on the shapes using the method called union(). Since this is a static method, you should call it using the class name (Shape or its subclasses) as shown below.

Shape shape = Shape.subtract(circle1, circle2); 

Example

Following is an example of the union operation. In here, we are drawing two circles and performing a union operation on them. Save this code in a file with the name unionExample.java.

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 UnionExample extends Application {  
   @Override 
   public void start(Stage stage) { 
      //Drawing Circle1 
      Circle circle1 = new Circle();         
      
      //Setting the position of the circle 
      circle1.setCenterX(250.0f); 
      circle1.setCenterY(135.0f); 
      
      //Setting the radius of the circle 
      circle1.setRadius(100.0f); 
      
      //Setting the color of the circle 
      circle1.setFill(Color.DARKSLATEBLUE);     
       
      //Drawing Circle2 
      Circle circle2 = new Circle();         
      
      //Setting the position of the circle 
      circle2.setCenterX(350.0f);
      circle2.setCenterY(135.0f); 
      
      //Setting the radius of the circle 
      circle2.setRadius(100.0f); 
      
      //Setting the color of the circle  
      circle2.setFill(Color.BLUE);  
       
      //Performing union operation on the circle 
      Shape shape = Shape.union(circle1, circle2); 
      
      //Setting the fill color to the result 
      shape.setFill(Color.DARKSLATEBLUE); 
       
      //Creating a Group object  
      Group root = new Group(shape); 
         
      //Creating a scene object 
      Scene scene = new Scene(root, 600, 300);  
      
      //Setting title to the Stage 
      stage.setTitle("Union Example"); 
         
      //Adding scene to the stage  
      stage.setScene(scene); 
         
      //Displaying the contents of the stage 
      stage.show(); 
   }      
   public static void main(String args[]){ 
      launch(args); 
   } 
}       

Compile and execute the saved java file from the command prompt using the following commands.

javac UnionExample.java 
java UnionExample

On executing, the above program generates a JavaFX window displaying the following output −