rhythm() | Sass function | Creates a funky vertical rhythm.

_rhythm.scss

/**
 * Rhythm
 * ------------------------------------------------------------------------
 * rhythm()
 * @version 1.0 | April 25th 2013
 * @author  Beau Charman | @beaucharman | http://www.beaucharman.me
 * @link    https://gist.github.com/beaucharman/5459188/
 * @param  {em}    $fontsize   | em unit value
 * @param  {float} $lineheight | decimal value
 * @return {em}    em unit value
 *
 * Creates a funky vertical rhythm
 * Assuming a unitless line height and that we are working with ems for 
 * font sizes. perfect for dynamic vertical rhythm on headings.
 * The $lineheight can be set to a default value of the global line 
 * height of the project, rather than 1.4 (which is a good value anyway).
 * 
 * A quick note on heading typography
 *
 * A line-height of 1.4 across headings is fantastic. This keeps the 
 * top and bottom margins sizes relevent, but allows for a natural 
 * vertical gap between multiple heading lines. This is dependent on
 * the font, and size of course.
 */
 
@function rhythm($fontsize, $lineheight: 1.4) {
  @return ($lineheight + 0em) / $fontsize + 0em;
}