We have learned that the fill transition is used to change the colors of a shape area. Similar to it, the stroke transition is used to change the stroke color of a shape.

A shape in JavaFX can consist of three types of strokes: inside, outside and centered; with different properties applied to it. This transition is ignorant to the property of a stroke and instead just changes its color over a course of duration specified.

Stroke Transition

JavaFX offers stroke transition using the StrokeTransition class which belongs to the javafx.animation package. By importing this class, we can change the stroke color of any shape on a JavaFX application. To implement this animation, there are various properties this class provides −

• duration − The duration of this StrokeTransition.

• shape − The target shape of this StrokeTransition.

• fromValue − Specifies the start color value for this StrokeTransition.

• toValue − Specifies the stop color value for this StrokeTransition.

Example

Following is the program which demonstrates Stoke Transition in JavaFX. Save this code in a file with the name StrokeTransitionExample.java.

import javafx.animation.StrokeTransition; 
import javafx.application.Application; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.scene.paint.Color; 
import javafx.scene.shape.Circle; 
import javafx.stage.Stage; 
import javafx.util.Duration; 
         
public class StrokeTransitionExample extends Application { 
   @Override 
   public void start(Stage stage) {      
      //Drawing a Circle 
      Circle circle = new Circle(); 
      
      //Setting the position of the circle 
      circle.setCenterX(300.0f); 
      circle.setCenterY(135.0f); 
      
      //Setting the radius of the circle 
      circle.setRadius(100.0f); 
      
      //Setting the color of the circle 
      circle.setFill(Color.BROWN); 
      
      //Setting the stroke width of the circle 
      circle.setStrokeWidth(20); 
       
      //creating stroke transition  
      StrokeTransition strokeTransition = new StrokeTransition(); 
      
      //Setting the duration of the transition 
      strokeTransition.setDuration(Duration.millis(1000)); 
      
      //Setting the shape for the transition 
      strokeTransition.setShape(circle); 
      
      //Setting the fromValue property of the transition (color) 
      strokeTransition.setFromValue(Color.BLACK); 
      
      //Setting the toValue property of the transition (color) 
      strokeTransition.setToValue(Color.BROWN); 
       
      //Setting the cycle count for the transition 
      strokeTransition.setCycleCount(50); 
      
      //Setting auto reverse value to false 
      strokeTransition.setAutoReverse(false); 
      
      //Playing the animation 
      strokeTransition.play(); 
         
      //Creating a Group object  
      Group root = new Group(circle); 
         
      //Creating a scene object 
      Scene scene = new Scene(root, 600, 300);  
      
      //Setting title to the Stage 
      stage.setTitle("Stroke transition 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 --module-path %PATH_TO_FX% --add-modules javafx.controls StrokeTransitionExample.java 
java --module-path %PATH_TO_FX% --add-modules javafx.controls StrokeTransitionExample 

Output

On executing, the above program generates a JavaFX window as shown below.