Modify a loaded SVG document with Graphics2D?

Hi,

is it possible to load an SVG document from file and display it in an
SVGCanvas and additionally modify that document via a Graphics2D object?

For example, is the following possible:
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final JFrame jFrame= new JFrame();
final SVGCanvas canvas= new SVGCanvas();
canvas.setURI(new File("mySVGFile.svg").toURI().toString());
jFrame.getContentPane().add(canvas);
jFrame.pack();
jFrame.setVisible(true);

[...]

final SVGGraphics2D g= new SVGGraphics2D(canvas.getSVGDocument());
final Rectangle r= new Rectangle(10,10,100,100);
g.setPaint(Color.RED);
g.setStroke(new BasicStroke(15f));
g.draw(r);

[...]
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to modify the image in the canvas?
What I want to achieve is to paint on the loaded SVG File in the canvas.
The painted elements need to be visible additionally to the elements
loaded from the file.


Regards
Marco