docs: private void initGraphics() {
          if (Double.compare(getPrefWidth(), 0.0) <= 0 || Double.compare(getPrefHeight(), 0.0) <= 0 || Double.compare(getWidth(), 0.0) <= 0 ||
              Double.compare(getHeight(), 0.0) <= 0) {
              if (getPrefWidth() > 0 && getPrefHeight() > 0) {
                  setPrefSize(getPrefWidth(), getPrefHeight());
              } else {
                  setPrefSize(PREFERRED_WIDTH, PREFERRED_HEIGHT);
              }
          }
  
          getStyleClass().add("indicator");
  
          ring = new Circle(PREFERRED_WIDTH * 0.5);
          ring.setStrokeType(StrokeType.INSIDE);
          ring.setStrokeWidth(PREFERRED_WIDTH * 0.078125);
          ring.setStroke(getRingColor());
          ring.setFill(Color.TRANSPARENT);
  
          dot = new Circle(PREFERRED_WIDTH * 0.3125);
          dot.setFill(getDotOnColor());
  
          pane = new Pane(ring, dot);
  
          getChildren().setAll(pane);
      }