Example3T.java

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.Group;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.image.Image;

import javafx.animation.Timeline;
import javafx.animation.KeyFrame;
import javafx.util.Duration;
import javafx.event.EventHandler;
import javafx.event.ActionEvent;

// An alternative implementation of Example 3,
//    using the Timeline, KeyFrame, and Duration classes.

// Animation of Earth rotating around the sun. (Hello, world!)
public class Example3T extends Application 
{
    public static void main(String[] args) 
    {
        launch(args);
    }

    @Override
    public void start(Stage theStage) 
    {
        theStage.setTitle( "Timeline Example" );
        
        Group root = new Group();
        Scene theScene = new Scene( root );
        theStage.setScene( theScene );
        
        Canvas canvas = new Canvas( 512, 512 );
        root.getChildren().add( canvas );
        
        GraphicsContext gc = canvas.getGraphicsContext2D();
        
        Image earth = new Image( "earth.png" );
        Image sun   = new Image( "sun.png" );
        Image space = new Image( "space.png" );
        
        Timeline gameLoop = new Timeline();
        gameLoop.setCycleCount( Timeline.INDEFINITE );
        
        final long timeStart = System.currentTimeMillis();
        
        KeyFrame kf = new KeyFrame(
            Duration.seconds(0.017),                // 60 FPS
            new EventHandler<ActionEvent>()
            {
                public void handle(ActionEvent ae)
                {
                    double t = (System.currentTimeMillis() - timeStart) / 1000.0; 
                                
                    double x = 232 + 128 * Math.cos(t);
                    double y = 232 + 128 * Math.sin(t);
                    
                    // Clear the canvas
                    gc.clearRect(0, 0, 512,512);
                    
                    // background image clears canvas
                    gc.drawImage( space, 0, 0 );
                    gc.drawImage( earth, x, y );
                    gc.drawImage( sun, 196, 196 );
                }
            });
        
        gameLoop.getKeyFrames().add( kf );
        gameLoop.play();
        
        theStage.show();
    }
}