Taking snapshots of JavaFX TextArea and WebView - javafx

Question

I have the following problem:
I'm writing a program that is like a blank paper where you can write on (free hand-writing), insert text, add images, add pdfs etc...
For one specific feature I need to convert the Nodes added to the Pane by the user to images. Thankfully, JavaFX-Nodes provide a nice method:
public void snapshot(...)
But there is one issue: When I'm trying to make Snapshots of text-objects they fail. The only Node that I can take snapshots of is javafx.scene.text.Text.
The following classes fail:
javafx.scene.control.TextArea
javafx.scene.web.WebView
Here is an example to illustrate my problem:
import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.SnapshotParameters;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.control.TextArea;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.text.Text;
public class Main extends Application {
#Override
public void start(Stage primaryStage) {
try {
TextArea textArea = new TextArea("Lorem Ipsum is simply dummy text"
+ " of the printing and typesetting industry. Lorem Ipsum has been \n"
+ "the industry's standard dummy text ever since the 1500s, when an \n"
+ "unknown printer took a galley of type and scrambled it to make a type\n"
+ " specimen book. It has survived not only five centuries, but also the\n"
+ " leap into electronic typesetting, remaining essentially unchanged. It\n"
+ " was popularised in the 1960s with the release of Letraset sheets containing\n"
+ " Lorem Ipsum passages, and more recently with desktop publishing software \n"
+ "like Aldus PageMaker including versions of Lorem Ipsum");
SnapshotParameters snapshotParameters = new SnapshotParameters();
snapshotParameters.setFill(Color.TRANSPARENT);
Image img = textArea.snapshot(snapshotParameters, null);
ImageView imgVw = new ImageView( img );
System.out.printf("img.width: %s height: %s%n", img.getWidth(), img.getHeight()); // <= width and height of the image img is 1:1! WHY?
Pane pane = new Pane();
pane.getChildren().addAll(imgVw);
Scene scene = new Scene(pane, 800,800);
pane.setMinWidth(800);
pane.setMinHeight(800);
pane.setMaxWidth(800);
pane.setMaxHeight(800);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
I could think of a work-around by creating a javafx.scene.text.Text-Object and take a snapshot of that. But this will fail for formatted Text displayed by javafx.scene.web.WebView.
Thanks in advance for your help!

Answer 1

The TextArea needs to be a Scene before you snapshot it. Add the following line to your code before the snapshot call and the code will work as you expect:
Scene snapshotScene = new Scene(textArea);
This requirement is mentioned in the snapshot javadoc:
NOTE: In order for CSS and layout to function correctly, the node must
be part of a Scene (the Scene may be attached to a Stage, but need not
be).