Responsive Sprite SASS Mixin

_responsive-sprite-mixin.scss

// Responsive Sprites
// example - @include responsive-sprite(346px, 2192px, 173px, 274px, 0px, 0px);
@mixin responsive-sprite($sprite-width, $sprite-height, $img-width, $img-height, $img-x, $img-y) {
	background-size: percentage($sprite-width/$img-width) percentage($sprite-height/$img-height);
	background-position: percentage($img-x/($sprite-width - $img-width)) percentage($img-y/($sprite-height - $img-height));
}