An example for background origin.

doc-src/content/examples/compass/css3/background-origin.haml

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+---
+title: Background Origin
+description: See background origin in action.
+framework: compass
+stylesheet: compass/css3/_background_origin.sass
+example: true
+---
+= render "partials/example"

doc-src/content/examples/compass/css3/background-origin/markup.haml

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+.example
+  #padding-box(style="background-image: url(background/);")
+    Padding Box
+  #border-box(style="background-image: url(background/);")
+    Border Box
+  #content-box(style="background-image: url(background/);")
+    Content Box

doc-src/content/examples/compass/css3/background-origin/stylesheet.sass

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+@import compass/css3
+
+.example
+  padding: 2em
+  div
+    background:
+      repeat: repeat
+      position: top left
+    border: 10px solid rgba(255, 0, 0, 0.5)
+    color: white
+    +text-shadow(darken(#00f, 50%), 2px, 2px)
+    padding: 1em
+    text-align: center
+    margin-bottom: 2em
+  #padding-box
+    +background-origin("padding-box")
+  #border-box
+    +background-origin("border-box")
+  #content-box
+    +background-origin("content-box")

frameworks/compass/stylesheets/compass/css3/_background_origin.sass

@@ -1,13 +1,17 @@
 //
-  Position the background off the edge of the padding, border or content
-  
-  * Possible values: [padding-box | border-box | content-box]
-  * browser defaults to padding-box, mixin defaults to content-box
-
-  Override constants to change defaults.
+  Override `!default_background_origin` to change the default.
 
 !default_background_origin ||= "content-box"
 
+//
+  Position the background off the edge of the padding, border or content
+
+  * Possible values:
+    * `"padding-box"`
+    * `"border-box"`
+    * `"content-box"`
+  * browser defaults to `"padding-box"`
+  * mixin defaults to `"content-box"`
 =background-origin(!origin = !default_background_origin)
   // webkit and mozilla use the deprecated short [border | padding | content]
   !deprecated= "padding"