我可以以编程方式捕获场景的快照吗？

我有以下代码可以正常工作..

import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.image.WritableImage;
import javafx.scene.web.WebView;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/* User: [email protected] Date: 2017/05/23 */
public class CaptureScene {

    public static void main(String[] args) throws IOException {
        JFXPanel jfxPanel = new JFXPanel();
        Platform.runLater(() -> {
            WebView webView = new WebView();
            webView.getEngine().load("file:///Users/koraytugay/Desktop/sample.html");
            jfxPanel.setScene(new Scene(webView));

            final JFrame jFrame = new JFrame();
            jFrame.setLayout(new FlowLayout());
            jFrame.getContentPane().add(jfxPanel);

            final JButton saveAsImage = new JButton("Save as Image");
            jFrame.getContentPane().add(saveAsImage);
            saveAsImage.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    Platform.runLater(new Runnable() {
                        @Override
                        public void run() {
                            final Scene scene = jfxPanel.getScene();
                            WritableImage image = scene.snapshot(new WritableImage(1920, 1080));
                            BufferedImage bufferedImage = SwingFXUtils.fromFXImage(image, null);
                            try {
                                ImageIO.write(bufferedImage, "png", new File("/Users/koraytugay/Desktop/vaaappp.png"));
                            } catch (IOException va) {
                                va.printStackTrace();
                            }
                        }
                    });
                }
            });

            jFrame.setSize(1920, 1080);
            jFrame.setVisible(true);
            jFrame.requestFocus();
        });
    }
}

所以当我运行这个应用程序时，sample.html 会被很好地呈现，当我点击 jframe 上的按钮时，它会被保存为一个图像就好了。

但是，我不想打扰按下按钮，这就是我正在尝试的..

import javafx.application.Platform;
import javafx.embed.swing.JFXPanel;
import javafx.embed.swing.SwingFXUtils;
import javafx.scene.Scene;
import javafx.scene.image.WritableImage;
import javafx.scene.web.WebView;

import javax.imageio.ImageIO;
import javax.swing.*;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

/* User: [email protected] Date: 2017/05/23 */
public class CaptureScene {

    public static void main(String[] args) throws IOException {
        JFXPanel jfxPanel = new JFXPanel();
        Platform.runLater(() -> {
            WebView webView = new WebView();
            webView.getEngine().load("file:///Users/koraytugay/Desktop/sample.html");
            jfxPanel.setScene(new Scene(webView));

            final JFrame jFrame = new JFrame();
            jFrame.setLayout(new FlowLayout());
            jFrame.getContentPane().add(jfxPanel);


            jFrame.setSize(1920, 1080);
            jFrame.setVisible(true);
            jFrame.requestFocus();


            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            Platform.runLater(new Runnable() {
                @Override
                public void run() {
                    final Scene scene = jfxPanel.getScene();
                    WritableImage image = scene.snapshot(new WritableImage(1920, 1080));
                    BufferedImage bufferedImage = SwingFXUtils.fromFXImage(image, null);
                    try {
                        ImageIO.write(bufferedImage, "png", new File("/Users/koraytugay/Desktop/baanb.png"));
                    } catch (IOException va) {
                        va.printStackTrace();
                    }
                }
            });

        });
    }
}

但保存的图像只是一个空白的白色图像。我错过了什么？基本上，我试图将 html 页面另存为 png，我采取了错误的方法吗？我应该用其他方式做到这一点吗？实际上，这将在服务器端运行，所以 JFrame 可能根本不起作用？