function calcWH(
  positionParams: PositionParams,
  width: number,
  height: number,
  x: number,
  y: number,
  handle: string
): { w: number, h: number }
Given a height and width in pixel values, calculate grid units.
@param  {PositionParams} positionParams  Parameters of grid needed for coordinates calcluations.
@param  {Number} height                  Height in pixels.
@param  {Number} width                   Width in pixels.
@param  {Number} x                       X coordinate in grid units.
@param  {Number} y                       Y coordinate in grid units.
@param {String} handle Resize Handle.
@return {Object}                         w, h as grid units.