Creating a image of CSS Sprite using compass

_retina-sprite-background.scss

//  Mixin for Creating a image of CSS Sprite using compass against Retina
//  For use:
//  .pdf-icon {
//     @include retina-sprite-background(pdf);
//  }
//

$sprite-map: sprite-map("sprite/*.png", $spacing: 100px);
$sprite-path: sprite-path($sprite-map);
$sprites-img: sprite-url($sprite-map);
$sprite-size: (image-width($sprite-path) / 2) (image-height($sprite-path) / 2);
@mixin retina-sprite-background($name) {
	$image:    sprite-file($sprite-map, $name);
	$position: round(nth(sprite-position($sprite-map, $name), 2) / 2);
	background-image: $sprites-img;
	background-position: 0 $position;
	background-repeat: no-repeat;
	@include background-size($sprite-size);
	width: image-width($image) / 2;
	height: image-height($image) / 2;
	display: block;
}