Plugin.backend = backend;
shapeFactories = new HashMap<String, ShapeFactory>();
shapeFactories.put(Line.NAME, new LineFactory());
shapeFactories.put(Polyline.NAME, new PolylineFactory());
shapeFactories.put(Rectangle.NAME, new RectangleFactory());
shapeFactories.put(Ellipse.NAME, new EllipseFactory());
shapeFactories.put(Polygon.NAME, new PolygonFactory());
shapeFactories.put(TextShape.NAME, new TextShapeFactory());
}