/// Returns a normal or 2x image depending on the DPI of the screen.
///
/// @author David Annez
///
/// @param {String} $image-path
///   The path to the image
///
/// @param {String} $format [".png"]
///   The format of the file

@mixin hidpi-image($image-path, $format: ".png") {
  $width: #{image-width(#{$image-path}#{$format})};
  $height: #{image-height(#{$image-path}#{$format})};

  background-size: unquote("#{$width} #{$height}");
  background-image: image-url("#{$image-path}#{$format}");
  @media screen and (-webkit-min-device-pixel-ratio: 1.5), screen and (min--moz-device-pixel-ratio: 1.5), screen and (-o-device-pixel-ratio: 3 / 2), screen and (min-device-pixel-ratio: 1.5) {
    background-image: image-url("#{$image-path}-2x#{$format}");
  }
}