cap-height-to-font-size.scss

/*
  When measuring type in comps using a cross-hair tool you may not
  always have a descender to check the font-size in pixels, meaning in most cases
  (especially for all-caps titles) you only have the ability to measure from
  baseline to cap-height.

  This algorithm will help you convert that cap-height measurement into the correct
  font-size within about pixel (often it's less than half a pixel off).

  Adjust for optics and browser-rendering on case-by-case basis.

  @return scaled unit (more than likely this will be px but it's not enforced)
*/
@function cap-height-to-font-size($cap-height, $unit-tweak: 0) {
  @return ((16 / 13) * $cap-height) + $unit-tweak;
}