import java.nio.IntBuffer;
import javafx.animation.AnimationTimer;
import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.image.PixelWriter;
import javafx.scene.image.WritablePixelFormat;
import javafx.scene.paint.Color;
import javafx.scene.paint.CycleMethod;
import javafx.scene.paint.LinearGradient;
import javafx.scene.paint.Stop;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.stage.StageStyle;
import javafx.util.Duration;

public class LostBackBuffer extends Application {
    static final int W = 400;
    static final int H = 400;

    @Override
    public void start(Stage stage) {
        Group root = new Group();
        Rectangle bg =
            new Rectangle(W, H, new LinearGradient(0, 0, W, H, false, CycleMethod.NO_CYCLE,
                                                   new Stop(0, Color.BLUE),
                                                   new Stop(1, Color.GREEN)));
        root.getChildren().add(bg);
        
        Rectangle r = new Rectangle(50, 50, Color.RED);
        r.setX(100);
        r.setY(100);
        Timeline t = new Timeline(new KeyFrame(Duration.seconds(1),
                                               new KeyValue(r.xProperty(), 300)));
        t.setAutoReverse(true);
        t.setCycleCount(Timeline.INDEFINITE);
        t.play();
        root.getChildren().add(r);

        stage.setScene(new Scene(root, W, H));
        stage.setX(0);
        stage.show();

        final Canvas cv = new Canvas(2000, 2000);
        cv.setTranslateX(0);
        cv.setTranslateY(200);
        Stage stage2 = new Stage(StageStyle.DECORATED);
        stage2.setScene(new Scene(new Group(cv), W, H));
        stage2.setX(W+100);
        Platform.runLater(() -> stage2.show());

        final int buf[] = new int[2000 * 2000+100];
        for (int i = 0; i < buf.length; i++) {
            buf[i] = 0xff000000 | (int) (Math.random() * 0xffffff);
        }
        new AnimationTimer() {
            int off;
            @Override
            public void handle(long now) {
                WritablePixelFormat<IntBuffer> wpf = WritablePixelFormat.getIntArgbPreInstance();
                PixelWriter pw = cv.getGraphicsContext2D().getPixelWriter();
                pw.setPixels(0, 0, 2000, 2000, wpf, buf, off, 2000);
                off++;
                if (off >= 100) off = 0;
            }
        }.start();
    }
}