setBrush(option) {
    const drawingMode = this._drawingMode;
    let compName = components.FREE_DRAWING;

    if (drawingMode === drawingModes.LINE_DRAWING) {
      compName = components.LINE;
    }

    this.getComponent(compName).setBrush(option);
  }
Set brush option
@param {Object} option brush option
 @param {Number} option.width width
 @param {String} option.color color like 'FFFFFF', 'rgba(0, 0, 0, 0.5)'