@charset "utf-8";

/*
 * @description: header css
 * @author: chenglong.wang@yoho.cn
 * @date: 2015/4/16
 */

//------------------------------------------------

/*
 * @description:用于生成retina下的图片精灵
 */

@mixin retina-sprite ($map,$sprite,$horizontal: false,$vertical: false) {

  $width: image-width(sprite-file($map, $sprite));
  $height: image-height(sprite-file($map, $sprite));
  $offsetY: ceil(nth(sprite-position($map,$sprite),2)/2);

  background: sprite-url($map) 0 $offsetY no-repeat;

  $zoomX: ceil(image_width(sprite-path($map))/2);
  $zoomY: auto;
  @include background-size($zoomX $zoomY);

  display: block;
  width: ceil($width/2)+1;
  height: ceil($height/2)+1;


  $ifabsolute: true;

  @if $horizontal {

    @if $ifabsolute {
      position: absolute;
      $ifabsolute: false;
    }

    @if $horizontal == true {
      left: 50%;
      margin-left: -(round($width/4));
    }
    @else{
      left: $horizontal;
    }
  }


  @if $vertical {

    @if $ifabsolute {
      position: absolute;
      $ifabsolute: false;
    }

    @if $vertical == true {
      top: 50%;
      margin-top: -(round($height/4));
    }
    @else{
      top: $vertical;
    }
  }
}

/*
 * @description:用于生成retina下的背景图片
 */

@mixin retain-background ($url) {
  background: image-url($url) center center no-repeat;
  $width: image-width($url);
  @include background-size($width/2 auto);
}