function scaleY(_scaleY) {
    var scaleX = this.imageData.scaleX;
    return this.scale(isNumber(scaleX) ? scaleX : 1, _scaleY);
  }
function scaleY(_scaleY) {
    var scaleX = this.imageData.scaleX;
    return this.scale(isNumber(scaleX) ? scaleX : 1, _scaleY);
  }
function scaleY ( _scaleY ) { var scaleX = this . imageData . scaleX ; return this . scale ( isNumber ( scaleX ) ? scaleX : 1 , _scaleY ) ; }
Scale the image on the y-axis.
@param {number} scaleY - The scale ratio on the y-axis.
@returns {Cropper} this
Scale the image on the y - axis .