import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ScrollPane;
import javafx.scene.input.ScrollEvent;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

/**
 *
 * @author Stanislav Smirnov <stanislav.smirnov@oracle.com>
 */
public class ScrollbarsTest extends Application {

    boolean scrollDown = true;

    public static void main(String[] args) {
        Application.launch(args);
    }

    @Override
    public void start(Stage stage) throws Exception {

        Scene scene = new Scene(new Group(), 200, 200);
        Group root = (Group)scene.getRoot();

        final Rectangle rectangle = new Rectangle(300, 300);
        rectangle.setFill(Color.WHITE);

        final ScrollPane sp = new ScrollPane();
        sp.setContent(rectangle);
        sp.setPrefSize(150, 150);
        sp.setLayoutX(20);
        sp.setLayoutY(40);

        Button button = new Button("Scroll");
        button.setOnAction(new EventHandler<ActionEvent>() {
            @Override public void handle(ActionEvent e) {
                if (sp.getHvalue() > 0.8 && scrollDown == true) {
                    scrollDown = false;
                }
                else if (sp.getHvalue() < 0.3) {
                    scrollDown = true;
                }

                if (scrollDown) {
                    Event.fireEvent(rectangle,
							new ScrollEvent(ScrollEvent.SCROLL, 
								50, 50, 50, 50, 
								false, false, false, false, true, false, 
								-50.0, -50.0, -50.0, -50.0, 
								ScrollEvent.HorizontalTextScrollUnits.NONE, 10.0, 
								ScrollEvent.VerticalTextScrollUnits.NONE, 10.0, 
								0));
                }
                else {
                    Event.fireEvent(rectangle,
							new ScrollEvent(ScrollEvent.SCROLL, 
								50, 50, 50, 50, 
								false, false, false, false, true, false, 
								50.0, 50.0, 50.0, 50.0, 
								ScrollEvent.HorizontalTextScrollUnits.NONE, 10.0, 
								ScrollEvent.VerticalTextScrollUnits.NONE, 10.0, 
								0));
                }
            }
        });

        root.getChildren().addAll(sp, button);
        stage.setScene(scene);
        stage.show();
    }

}