resizeHandlebar() {
    let vh = this.viewHeight
    let h = vh * vh / this.height
    this.handlebar.resize(h)
  }
/**
   * show the handlebar and size it
   * @api public
   */
show the handlebar and size it
@api public
show the handlebar and size it @api public
resizeHandlebar() {
    let vh = this.viewHeight
    let h = vh * vh / this.height
    this.handlebar.resize(h)
  }
resizeHandlebar ( ) { let vh = this . viewHeight let h = vh * vh / this . height this . handlebar . resize ( h ) }
show the handlebar and size it
 @api public
show the handlebar and size it @api public