Retina Sprite

_retina-sprite.sass

@import "compass/utilities/sprites/base"
@import "compass/css3/inline-block"
@import "compass/css3/background-size"

@mixin retina-sprite($folder)
  $sprites: sprite-map("#{$folder}/*.png")
  // Generates a sprite containing every icon in the supplied folder.
  $sprites-2x: sprite-map("#{$folder}@2x/*.png")
  // Generates a second sprite containing every icon @2x resolution.

  background-image: sprite-url($sprites)
  background-repeat: no-repeat
  @include inline-block
  text-indent: -9999px
  @each $sprite in sprite-names($sprites)
    &.#{$sprite}
      background-position: sprite-position($sprites, $sprite)
      height: image-height(sprite-file($sprites, $sprite))
      width: image-width(sprite-file($sprites, $sprite))

  @media (min-resolution: 2 dppx), (min-device-pixel-ratio: 2), (-o-min-device-pixel-ratio: 2/1), (-webkit-min-device-pixel-ratio: 2)
    background-image: sprite-url($sprites-2x)
    @include background-size(sprite-size($sprites))
    @each $sprite in sprite-names($sprites-2x)
      &.#{$sprite}
        background-position: nth(sprite-position($sprites-2x, $sprite), 1) nth(sprite-position($sprites-2x, $sprite), 2) / 2


// .test

//  @include retina-sprite("cutlery")

Needs Patch
https://github.com/cwerner1/compass/commit/93224b6f8c5e9f407f33e4771b9b7e2f48051565