import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
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.input.MouseEvent;
import javafx.scene.paint.Color;
import javafx.scene.text.TextAlignment;
import javafx.stage.Stage;
import javafx.util.Duration;

public class NullCanvasTextAlign extends Application {
    public static void main(String argv[]) {
        launch(argv);
    }

    void render(GraphicsContext gc, double hue) {
        gc.setFill(Color.hsb(hue, 1.0, 1.0));
        gc.fillRect(0, 0, 300, 300);
        gc.setFill(Color.BLACK);
        gc.fillText("Null test", 20, 20);
    }

    @Override
    public void start(Stage stage) {
        Canvas c = new Canvas(300, 300);
        final GraphicsContext gc = c.getGraphicsContext2D();
        render(gc, 0.0);

        final DoubleProperty hue = new SimpleDoubleProperty();
        hue.addListener(new InvalidationListener() {
            public void invalidated(Observable observable) {
                render(gc, hue.get());
            }
        });

        Scene scene = new Scene(new Group(c));
        scene.addEventHandler(MouseEvent.MOUSE_CLICKED, new EventHandler<MouseEvent>() {
            public void handle(MouseEvent event) {
                if (gc.getTextBaseline() != null) {
                    System.out.println("setting to null");
                    gc.setTextAlign(null);
                } else {
                    System.out.println("setting to LEFT");
                    gc.setTextAlign(TextAlignment.LEFT);
                }
            }
        });
        stage.setScene(scene);
        stage.show();

        KeyValue kv = new KeyValue(hue, 360.0);
        KeyFrame kf = new KeyFrame(Duration.seconds(5), kv);
        Timeline tl = new Timeline(kf);
        tl.setCycleCount(Timeline.INDEFINITE);
        tl.play();
    }
}