JavaFX - Come creare SnapShot/Screenshot di (invisibile) WebView

Question

Voglio creare uno SnapShot/Screenshot/Immagine da una WebView in JavaFX (8).
Questa WebView non deve essere visibile (nel mio caso).

La mia domanda:
E 'possibile (in qualsiasi modo), per creare una schermata/Immagine da una WebView,
quando il WebView è non visibile (o non aggiunti a qualsiasi contenitore visibile)?

Vedi il mio codice di esempio, quando WebView (o è genitore ScrollPane) è visibile = false,
lo screenshot non funziona (rispettivamente è vuoto Fai/vuoto).

codice Esempio:

package test; 

import javafx.animation.KeyFrame; 
import javafx.animation.Timeline; 
import javafx.application.Application; 
import javafx.beans.value.ChangeListener; 
import javafx.beans.value.ObservableValue; 
import javafx.concurrent.Worker; 
import javafx.geometry.Pos; 
import javafx.scene.Scene; 
import javafx.scene.SnapshotResult; 
import javafx.scene.control.Label; 
import javafx.scene.control.ScrollPane; 
import javafx.scene.image.ImageView; 
import javafx.scene.layout.VBox; 
import javafx.scene.web.WebView; 
import javafx.stage.Stage; 
import javafx.util.Duration; 

public class JavaFXApplication extends Application 
{ 
    @Override 
    public void start(Stage primaryStage) 
    { 
     ImageView webviewPreviewImage = new ImageView(); 
     Label waitLabel = new Label("Please wait..."); 
     WebView webView = new WebView(); 
     webView.setMaxHeight(480d); 
     webView.setMinHeight(480d); 
     webView.setMaxWidth(640d); 
     webView.setMinWidth(640d); 
     webView.setZoom(0.4); 

     ScrollPane scrollpane = new ScrollPane(webView); 
     scrollpane.setHbarPolicy(ScrollPane.ScrollBarPolicy.NEVER); 
     scrollpane.setVbarPolicy(ScrollPane.ScrollBarPolicy.NEVER); 
     scrollpane.setMaxWidth(0); //WORKAROUND: hide the WebView/ScrollPane 
     scrollpane.setMaxHeight(0); //WORKAROUND: hide the WebView/ScrollPane 
     scrollpane.setMinWidth(0); //WORKAROUND: hide the WebView/ScrollPane 
     scrollpane.setMinHeight(0); //WORKAROUND: hide the WebView/ScrollPane 

     //scrollpane.setVisible(false); //when WebView is invisible, SnapShot doesn't work! 

     webView.getEngine().getLoadWorker().stateProperty().addListener(new ChangeListener<Worker.State>() 
     { 
      @Override 
      public void changed(ObservableValue ov, Worker.State oldState, Worker.State newState) 
      { 
       if (newState == Worker.State.SUCCEEDED) 
       { 
       //When SUCCEEDED is called, the WebPage may not has fully finished rendering! 
       //so, wait for few seceonds before making the screenshot... 
       Timeline timeline = new Timeline(new KeyFrame(
         Duration.millis(1500), 
         ae -> takeSnapshot())); 
       timeline.play(); 
       } 
      } 

      private KeyFrame takeSnapshot() 
      { 
       webView.snapshot((SnapshotResult param) -> 
       { 
       webviewPreviewImage.setImage(param.getImage()); 
       webviewPreviewImage.setFitHeight(240d); 
       webviewPreviewImage.setFitWidth(320d); 
       webviewPreviewImage.setPreserveRatio(true); 
       waitLabel.setVisible(false); 
       return null; 
       }, null, null); 
       return null; 
      } 
     }); 
     webView.getEngine().load("http://www.bing.com"); 

     VBox root = new VBox(); 
     root.setAlignment(Pos.CENTER); 
     root.setSpacing(10d); 
     root.getChildren().add(waitLabel); 
     root.getChildren().add(scrollpane); 
     root.getChildren().add(webviewPreviewImage); 

     Scene scene = new Scene(root, 800, 600); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } 

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

Answer 1

utilizzare la classe di robot per simulare dei tasti (Fn e PrintScreen), carico e poi ritagliarla.