JavaFX 2.0+ WebView/WebEngine 将网页呈现为图像

  
本文介绍了JavaFX 2.0+ WebView/WebEngine 将网页呈现为图像的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

I'm looking for a way to load up a page and save the rendering as an image just as you would do with CutyCapt (QT + webkit EXE to do just that).

At the moment and without JavaFX, I do it by calling an external process from java and rendering to file than loading that file into an ImageBuffer... Neither very optimized nor practical and even less cross platform...

Using JavaFX2+ I tried playing with the WebView & WebEngine:

public class WebComponentTrial extends Application {
    private Scene scene;

    @Override
    public void start(final Stage primaryStage) throws Exception {
        primaryStage.setTitle("Web View");
        final Browser browser = new Browser();
        scene = new Scene(browser, 1180, 800, Color.web("#666970"));
        primaryStage.setScene(scene);
        scene.getStylesheets().add("webviewsample/BrowserToolbar.css");
        primaryStage.show();
    }

    public static void main(final String[] args) {
        launch(args);
    }
}
class Browser extends Region {
    static { // use system proxy settings when standalone application
    // System.setProperty("java.net.useSystemProxies", "true");
    }

    final WebView browser = new WebView();
    final WebEngine webEngine = browser.getEngine();

    public Browser() {
        getStyleClass().add("browser");
        webEngine.load("http://www.google.com/");
        getChildren().add(browser);
    }

    @Override
    protected void layoutChildren() {
        final double w = getWidth();
        final double h = getHeight();
        layoutInArea(browser, 0, 0, w, h, 0, HPos.CENTER, VPos.CENTER);
    }

    @Override
    protected double computePrefWidth(final double height) {
        return 800;
    }

    @Override
    protected double computePrefHeight(final double width) {
        return 600;
    }
}

There is a deprecated method : renderToImage in Scene (see links below) that would do something that comes close and with which I'd might be able to work but it is deprecated... It being deprecated in JavaFX seems to mean that there is no javadoc advertising the replacement method and because I don't have access to the code, I cannot see how it was done...

Here are a couple of sites where I found some information but nothing to render a webpage to an image:

http://tornorbye.blogspot.com/2010/02/how-to-render-javafx-node-into-image.html

canvasImage and saveImage(canvasImage, fc.getSelectedFile()) from this one : 

http://javafx.com/samples/EffectsPlayground/src/Main.fx.html

Others: 

http://download.oracle.com/javafx/2.0/webview/jfxpub-webview.htm
http://download.oracle.com/javafx/2.0/get_started/jfxpub-get_started.htm
http://fxexperience.com/2011/05/maps-in-javafx-2-0/

解决方案

I have done this by launching JavaFX WebView on a Swing JFrame and JFXPanel. And then I use the paint() method on JFXPanel once the WebEngine status is SUCCEEDED.

You may follow this tutorial to make a WebView: Integrating JavaFX into Swing Applications

The code below demonstrate how I capture the rendered screen from JFXPanel.

public static void main(String args[]) {
    jFrame = new JFrame("Demo Browser");
    jfxPanel = new JFXPanel();
    jFrame.add(jfxPanel);
    jFrame.setVisible(true);
    jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    SwingUtilities.invokeLater(new Runnable() {
        @Override
        public void run() {
            Platform.runLater(new Runnable() {
                @Override
                public void run() {
                    browser = new FXBrowser();
                    jfxPanel.setScene(browser.getScene());
                    jFrame.setSize((int) browser.getWebView().getWidth(), (int) browser.getWebView().getHeight());

                    browser.getWebEngine().getLoadWorker().stateProperty().addListener(
                            new ChangeListener() {
                                @Override
                                public void changed(ObservableValue observable,
                                                    Object oldValue, Object newValue) {
                                    State oldState = (State) oldValue;
                                    State newState = (State) newValue;
                                    if (State.SUCCEEDED == newValue) {
                                        captureView();
                                    }
                                }
                            });
                }
            });
        }
    });
}

private static void captureView() {
    BufferedImage bi = new BufferedImage(jfxPanel.getWidth(), jfxPanel.getHeight(), BufferedImage.TYPE_INT_ARGB);
    Graphics graphics = bi.createGraphics();
    jfxPanel.paint(graphics);
    try {
        ImageIO.write(bi, "PNG", new File("demo.png"));
    } catch (IOException e) {
        e.printStackTrace();
    }
    graphics.dispose();
    bi.flush();
}

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