fixes #253

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    compass (0.11.beta.3.01b9cd3)
+    compass (0.11.beta.3.a9b6d8c)
       chunky_png (~> 1.1.0)
       sass (>= 3.1.0.alpha.249)
 

lib/compass/sass_extensions/sprites/base.rb

@@ -55,6 +55,7 @@ module Compass
             image
           end
         end
+        
         # Calculates the overal image dimensions
         # collects image sizes and input parameters for each sprite
         def compute_image_positions!

lib/compass/sass_extensions/sprites/image.rb

@@ -51,6 +51,10 @@ module Compass
           Digest::MD5.file(file).hexdigest
         end
 
+        def mtime
+          File.mtime(file)
+        end
+        
         private
           def dimensions
             @dimensions ||= Compass::SassExtensions::Functions::ImageSize::ImageProperties.new(file).size

spec/sprites_spec.rb

@@ -440,5 +440,32 @@ describe Compass::Sprites do
       }
     CSS
   end
+  
+  it "should calculate corret sprite demsions when givin spacing via issue#253" do
+    css = render <<-SCSS
+      $squares-spacing: 10px;
+      @import "squares/*.png";
+      .foo {
+        @include sprite-background-position($squares-sprites, "twenty-by-twenty");
+      }
+      .bar {
+        @include sprite-background-position($squares-sprites, "ten-by-ten");
+      }
+    SCSS
+    image_size('squares-*.png').should == [20, 40]
+    css.should == <<-CSS
+      .squares-sprite {
+        background: url('/squares-e3c68372d9.png') no-repeat;
+      }
+      
+      .foo {
+        background-position: 0 -20px;
+      }
+      
+      .bar {
+        background-position: 0 0;
+      }
+    CSS
+  end
 
 end