我可以以编程方式捕获场景的快照吗？答案

【问题标题】：Can I capture snapshot of scene programmatically?我可以以编程方式捕获场景的快照吗？
【发布时间】：2017-10-23 04:25:42
【问题描述】：

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: koray@tugay.biz 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 会很好地呈现，当我点击 jframe 上的按钮时，它会很好地保存为图像。

但是，我不想费心点击按钮，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: koray@tugay.biz 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张空白图像。我错过了什么？基本上，我正在尝试将 html 页面保存为 png，我是否采取了错误的方法？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，所以也许 JFrame 无论如何都不会工作？

【问题讨论】：

标签： java swing javafx

【解决方案1】：

向WebEngine 持有的stateProperty 添加合适的侦听器，以加载您的WebView。当worker的状态为SUCCEEDED时，调度快照。从这个example 开始，字段snapshot() 的webView 会产生显示的结果。

WebEngine webEngine = webView.getEngine();
Worker worker = webEngine.getLoadWorker();
worker.stateProperty().addListener((Observable o) -> {
    if (worker.getState() == Worker.State.SUCCEEDED) {
        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                WritableImage image = webView.snapshot(
                    new SnapshotParameters(), new WritableImage(800, 400));
                BufferedImage bufferedImage = SwingFXUtils.fromFXImage(image, null);
                try {
                    ImageIO.write(bufferedImage, "png", new File("image.png"));
                } catch (IOException va) {
                    va.printStackTrace();
                }
            }
        });
    }
});

【讨论】：