resize sprites in Compass

gistfile1.scss

@mixin resize-sprite($map, $sprite, $percent) {
  $spritePath:    sprite-path($map);
  $spriteWidth:   image-width($spritePath);
  $spriteHeight:  image-height($spritePath);
  $width: image-width(sprite-file($map, $sprite));
  $height: image-height(sprite-file($map, $sprite));

  @include background-size(ceil($spriteWidth * ($percent/100)) ceil($spriteHeight * ($percent/100)));
  width: ceil($width*($percent/100));
  height: ceil($height*($percent/100));
  background-position: 0 floor(nth(sprite-position($map, $sprite), 2)  * ($percent/100) );
}

Great mixin! But is it somehow possible to recreate all sprite-map classes again automatically for the second size?
I created a question here:
http://stackoverflow.com/questions/14135256/how-to-create-a-sprite-from-a-folder-with-and-without-background-size-using-com

hey, I did extend your implementation, also added files with usage examples: https://gist.github.com/wilkerlucio/6442309

my version has a mixin that resizes all the icons at once, which may be helpful :)

how can we rewrite the function to use px instead of % : I need my icon do a specific px size, not a percent of the original

@mixin resize-sprite($map, $sprite, $px_size) like that