import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.util.Duration;

/**
 *
 * @author kcr
 */
public class CanvasTest extends Application {

    private static final int WIDTH = 600;
    private static final int HEIGHT = 450;
    private static final int SIZE = 10;
    private static final int INC = 20;
    private static final int X_MIN = 10;
    private static final int Y_MIN = 10;
    private static final int X_MAX = WIDTH - SIZE;
    private static final int Y_MAX = HEIGHT - SIZE;

    Canvas canvas;
    double x = X_MIN;
    double y = Y_MIN;

    @Override public void start(Stage stage) {
        stage.setTitle("CanvasTest");

        Group root = new Group();
        Scene scene = new Scene(root, WIDTH, HEIGHT);

        canvas = new Canvas(WIDTH, HEIGHT);

        root.getChildren().add(canvas);
        stage.setScene(scene);
        stage.show();

        final GraphicsContext gc = canvas.getGraphicsContext2D();
        gc.setFill(Color.DARKBLUE);
        gc.fillRect(0, 0, WIDTH, HEIGHT);
        KeyFrame keyFrame = new KeyFrame(Duration.millis(100), new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent t) {
                gc.setFill(Color.RED);
                gc.fillRect(x, y, SIZE, SIZE);
                x += INC;
                if (x >= X_MAX) {
                    x = X_MIN;
                    y += INC;
                    if (y >= Y_MAX) {
                        gc.setFill(Color.DARKBLUE);
                        gc.fillRect(0, 0, WIDTH, HEIGHT);
                        y = Y_MIN;
                    }
                }
            }
        });
        Timeline t = new Timeline(keyFrame);
        t.setCycleCount(Timeline.INDEFINITE);
        t.play();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Application.launch(args);
    }
}