paint method
Implementation
void paint(ChartCanvas canvas) {
  canvas.drawingView = 'BaseView';
  _layoutManager.paintOrderedViews.forEach((LayoutView view) {
    canvas.drawingView = view.runtimeType.toString();
    view.paint(canvas, animatingThisDraw ? animationPercent : 1.0);
  });
  canvas.drawingView = 'PostRender';
  fireOnPostrender(canvas);
  canvas.drawingView = null;
  if (animationPercent == 1.0) {
    fireOnAnimationComplete();
  }
}