JavaFX - Stroke Property

The Stroke Fill property is used to change the colours of 2D object itself. However, we can also change the colour of a 2D object's boundary.

In JavaFX, while creating a 2D object, there are only two parts you can work with, if you want to improve the quality of the shape; i.e., the enclosed area of the shape and the boundary of the shape. Hence, the properties provided by JavaFX include designing both these parts.

In this chapter, we will learn about the Stroke property in detail.

Stroke Property

The Stroke property in JavaFX is used to change colours of the shape boundary. This property is of the type Paint and it represents the color of the boundary line of the shape. You can set a value to this property using the method setStroke(). This method is a part of javafx.scene.paint package and takes the Color object as a parameter value as shown below −

path.setStroke(Color.RED)

By default, the color of the stroke is black. Following is a diagram of a triangle with different stroke colors.

Example

We will see an example demonstrating how to colour the boundary of a 2D shape in JavaFX. In here, we are drawing a 2D shape, say a rectangle. By default, the rectangle will be coloured black; we will try to change its boundary colour to Violet. Save the file with the name StrokeExample.java.

import javafx.application.Application; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Shape;
import javafx.scene.paint.Color;
import javafx.stage.Stage;  

public class StrokeExample extends Application { 
   @Override 
   public void start(Stage stage) {        
      //Creating a Rectangle 
      Rectangle rectangle = new Rectangle(50.0f, 50.0f, 200.0f, 100.0f);  

      rectangle.setStroke(Color.VIOLET);
      rectangle.setStrokeWidth(7.0);

      //Creating a Group object  
      Group root = new Group(rectangle); 

      //Creating a scene object 
      Scene scene = new Scene(root, 300, 300);  

      //Setting title to the Stage 
      stage.setTitle("Drawing a Rectangle"); 

      //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 --module-path %PATH_TO_FX% --add-modules javafx.controls StrokeExample.java 
java --module-path %PATH_TO_FX% --add-modules javafx.controls StrokeExample

Output

On executing, the above program generates a JavaFX window displaying a rectangle with a stroke coloured violet as shown below.

Example

In this example, we are drawing a polygon and change its boundary colour to RED. Save the file with the name StrokePolygonExample.java.

import javafx.application.Application; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Shape;
import javafx.scene.paint.Color;
import javafx.stage.Stage;  

public class StrokePolygonExample extends Application { 
   @Override 
   public void start(Stage stage) {        
      //Creating a Polygon 
      Polygon polygon = new Polygon();  

      //Adding coordinates to the polygon 
      polygon.getPoints().addAll(new Double[]{ 
         100.0, 50.0, 
         200.0, 50.0, 
         250.0, 150.0,          
         200.0, 250.0, 
         100.0, 250.0,
      });  

      polygon.setStroke(Color.RED);
      polygon.setStrokeWidth(5.0);

      //Creating a Group object  
      Group root = new Group(polygon); 

      //Creating a scene object 
      Scene scene = new Scene(root, 300, 300);  

      //Setting title to the Stage 
      stage.setTitle("Drawing a Polygon"); 

      //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 --module-path %PATH_TO_FX% --add-modules javafx.controls StrokePolygonExample.java 
java --module-path %PATH_TO_FX% --add-modules javafx.controls StrokePolygonExample

Output

On executing, the above program generates a JavaFX window displaying a rectangle with a stroke coloured violet as shown below.