Question

I am trying to figure out how to implement background crop like this in Compass sprite:
http://nicolasgallagher.com/css-background-image-hacks/

http://jsfiddle.net/blineberry/BhbrL/

This is what I have in .sass file:

@import "buttons/*.png"
@include all-buttons-sprites

.buttons-arrow
  background-image: none
  width: 30px
  height: 45px

.buttons-arrow:before
  +buttons-sprites(arrow)
  display: block
  content: ""
  width: 15px
  height: 27px

As you see, I tried to make .buttons-arrow without the background image first and then I added back the background-image. However, it gave me this .css file:

.buttons-sprite, .buttons-arrow, .buttons-arrow:before .buttons-arrow {
  background: url('../images/buttons-s5ae2b3a1e9.png') no-repeat;
}

.buttons-arrow {
  background-position: 0 0;
}

.buttons-arrow:hover, .buttons-arrow.arrow_hover, .buttons-arrow.arrow-hover {
  background-position: 0 -27px;
}

.buttons-arrow {
  background-image: none;
  width: 30px;
  height: 45px;
  margin-left: 150px;
}

.buttons-arrow:before {
  display: block;
  content: "";
  width: 15px;
  height: 27px;
}

.buttons-arrow:before .buttons-arrow {
  background-position: 0 0;
}

.buttons-arrow:before .buttons-arrow:hover, .buttons-arrow:before .buttons-arrow.arrow_hover, .buttons-arrow:before .buttons-arrow.arrow-hover {
  background-position: 0 -27px;
}

.buttons-arrow:hover {
  background-color: #ea4800;
}

Obviously it was wrong because it combined into this .buttons-arrow:before .buttons-arrow

I just want a simple result like this

.buttons-arrow {
  width: 30px;
  height: 45px;
  margin-left: 150px;
}

.buttons-arrow:before {
  background-image: url('../images/buttons-s5ae2b3a1e9.png');
  display: block;
  content: "";
  height: 27px;
  width: 15px;

How do I code this in Compass using sprite?

Answer 1

Since this place is pretty much dead, I do will a favor for people searching this from Google. The answer is:

Put this on top:

$buttons: sprite-map("buttons/*.png")

I have arrow.png and arrow_hover.png in there. The idea is to use sprite-map functions instead of @import all. Then make sure to include background image for the :before pseudo element but not original content:

.buttons-arrow
  width: 50px
  height: 50px
  &::before
    content: ""
    background: sprite($buttons, arrow) no-repeat
    display: block
    position: relative
    width: 20px
    height: 20px
  &:hover
    background-color: gray
    &::before
      content: ""
      background: sprite($buttons, arrow_hover) no-repeat
      position: relative
      width: 20px
      height: 20px