CanvasBlink.java

import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
import javafx.scene.layout.StackPane;
import javafx.scene.Scene;


/**
 * User: hansolo
 * Date: 04.02.16
 * Time: 09:02
 */
public class BlinkTest extends Application {
    private Canvas          canvas;
    private GraphicsContext ctx;
    private boolean         toggle;
    private long            lastTimerCall;
    private AnimationTimer  timer;


    @Override public void init() {
        canvas        = new Canvas(200, 200);
        ctx           = canvas.getGraphicsContext2D();
        toggle        = true;
        lastTimerCall = System.nanoTime();
        timer = new AnimationTimer() {
            @Override public void handle(long now) {
                if (now > lastTimerCall + 500_000_000l) {
                    blink(toggle);
                    toggle = !toggle;
                    lastTimerCall = now;
                }
            }
        };
    }

    @Override public void start(Stage stage) {
        StackPane pane = new StackPane(canvas);
        pane.setPadding(new Insets(10));

        Scene scene = new Scene(pane);

        stage.setScene(scene);
        stage.show();

        timer.start();
    }

    private void blink(boolean on) {
        if (on) {
            ctx.setStroke(Color.RED);
            ctx.strokeLine(50, 100, 150, 100);
        } else {
            ctx.clearRect(49, 99, 151, 101);
        }
    }

    @Override public void stop() {
        System.exit(0);
    }

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