code: function (mode) {
              var baseVal = presentation.calculateZoomValue.call(this, mode);
              if (mode === ZOOM_FIT_WIDTH) {
                  baseVal /= 2;
              }
              return baseVal;
          }
docs: Calculate the numeric value for a given zoom mode (or return the value if it's already numeric)
  @param   {string} mode The mode to zoom to
  @returns {float}       The zoom value