_retina-border.sass

/*  Retina-Border SASS Mixin
 *  The MIT License (MIT)
 *  Copyright (c) 2015 Malik Dellidj – @Dathink
 *
 *  – How to use : 
 *  .foo
 *
 *    +retina-border(top $primary-color, bottom #bada55)
 *  You can use : top, right, bottom, left directions in the order of your choice.
 *  The color is always after the direction, and separated by a space.
 *  Obviously if you don't specify, no border.   
 */

=retina-border($v...)
  $o: ()
  $r: ()
  $pY: 0
  $pX: 0
  $h: 0
  $w: 0
  @each $d in $v
    $p: nth($d, 1)
    $c: nth($d, 2)
    @if $p == bottom or $p == top
      $r: repeat-x
      $h: "0.5"
      $w: "1"
      @if $p == bottom
        $pY: "0.5"
    @else
      $r: repeat-y
      $h: "1"
      $w: "0.5"
      $pY: "0"
      @if $p == right
        $pX: "0.5"

    $m: $r $p url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='1' height='1'><rect x='#{$pX}' y='#{$pY}' width='#{$w}' height='#{$h}' fill='#{$c}'/></svg>")
    $o: append($o, $m, comma)
      
  background: $o