resetSize(width, height) {
    if (!width) {
      width = this.getConf('width');
      height = this.getConf('height');
    }

    this.setConf('width', Utils.courtship(width));
    this.setConf('height', Utils.courtship(height));
  }
Set the stage size of the scene
@param {number} width - stage width
@param {number} height - stage height
@public