setBrush(setting) {
    const brush = this.getCanvas().freeDrawingBrush;

    setting = setting || {};
    this.width = setting.width || this.width;
    if (setting.color) {
      this.oColor = new fabric.Color(setting.color);
    }
    brush.width = this.width;
    brush.color = this.oColor.toRgba();
  }
Set brush
@param {{width: ?number, color: ?string}} [setting] - Brush width & color