added positioning of images

lib/compass/sass_extensions/functions/sprites.rb

@@ -1,11 +1,12 @@
 require 'chunky_png'
 
 module Compass::SassExtensions::Functions::Sprites
+  SASS_NULL = Sass::Script::Number::new(0)
+  
   def sprite_image(uri)
     uri = uri.value
     path, name = Compass::Sprites.path_and_name(uri)
     last_spacing = 0
-    default_spacing = number_from_var("#{name}-spacing")
     width = 0
     height = 0
     images = Compass::Sprites.sprites(name)
@@ -14,7 +15,7 @@ module Compass::SassExtensions::Functions::Sprites
     images.each do |image|
       current_spacing = number_from_var("#{name}-#{image[:name]}-spacing")
       if height > 0
-        height += [current_spacing, last_spacing, default_spacing].max
+        height += [current_spacing, last_spacing].max
       end
       image[:y] = height
       height += image[:height]
@@ -26,21 +27,32 @@ module Compass::SassExtensions::Functions::Sprites
     output_png = ChunkyPNG::Image.new(width, height, ChunkyPNG::Color::TRANSPARENT)
     images.each do |image|
       input_png  = ChunkyPNG::Image.from_file(image[:file])
-      x = 0
+      position = environment.var("#{name}-#{image[:name]}-position")
-      y = image[:y]
+      if position.unit_str == "%"
-      output_png.replace input_png, x, y
+        image[:x] = (width - image[:width]) * (position.value / 100)
+      else
+        image[:x] = position.value
+      end
+      output_png.replace input_png, image[:x], image[:y]
     end
     output_png.save File.join(File.join(Compass.configuration.images_path, "#{path}.png"))
     
     image_url(Sass::Script::String.new("#{path}.png"))
   end
 
-  def sprite_position(file)
+  def sprite_position(file, x_shift = SASS_NULL, y_shift = SASS_NULL)
     name = File.dirname(file.value)
-    sprite = File.basename(file.value, '.png')
+    image_name = File.basename(file.value, '.png')
-    y = Compass::Sprites.sprites(name).detect{ |sprite_info| sprite_info[:name] == sprite }[:y]
+    image = Compass::Sprites.sprites(name).detect{ |image| image[:name] == image_name }
-    y = "-#{y}px" unless y == 0
+    if x_shift.unit_str == "%"
-    Sass::Script::String.new("0 #{y}")
+      x = x_shift.to_s
+    else
+      x = x_shift.value - image[:x]
+      x = "#{x}px" unless x == 0
+    end
+    y = y_shift.value - image[:y]
+    y = "#{y}px" unless y == 0
+    Sass::Script::String.new("#{x} #{y}")
   end
   
 private

lib/compass/sprites.rb

@@ -42,6 +42,15 @@ module Compass
         contents = <<-SCSS
           $#{name}-sprite-base-class: ".#{name}-sprite" !default;
           $#{name}-sprite-dimensions: false !default;
+          $#{name}-position: 0% !default;
+          $#{name}-spacing: 0 !default;
+
+          #{images.map do |sprite| 
+            <<-SCSS
+              $#{name}-#{sprite[:name]}-position: $#{name}-position !default;
+              $#{name}-#{sprite[:name]}-spacing: $#{name}-spacing !default;
+            SCSS
+          end.join}
         
           \#{$#{name}-sprite-base-class} {
             background: sprite-image("#{uri}") no-repeat;
@@ -52,13 +61,13 @@ module Compass
             width: image-width("#{name}/\#{$sprite}.png");
           }
           
-          @mixin #{name}-sprite-position($sprite) {
+          @mixin #{name}-sprite-position($sprite, $x: 0, $y: 0) {
-            background-position: sprite-position("#{path}/\#{$sprite}.png");  
+            background-position: sprite-position("#{path}/\#{$sprite}.png", $x, $y);  
           }
         
-          @mixin #{name}-sprite($sprite, $dimensions: $#{name}-sprite-dimensions) {
+          @mixin #{name}-sprite($sprite, $dimensions: $#{name}-sprite-dimensions, $x: 0, $y: 0) {
             @extend \#{$#{name}-sprite-base-class};
-            @include #{name}-sprite-position($sprite);
+            @include #{name}-sprite-position($sprite, $x, $y);
             @if $dimensions {
               @include #{name}-sprite-dimensions($sprite);
             }
@@ -66,8 +75,12 @@ module Compass
         
           @mixin all-#{name}-sprites {
             #{images.map do |sprite| 
-                %Q(.#{name}-#{sprite[:name]} { @include #{name}-sprite("#{sprite[:name]}"); })
+              <<-SCSS
-              end.join}
+                .#{name}-#{sprite[:name]} {
+                  @include #{name}-sprite("#{sprite[:name]}");
+                }
+              SCSS
+            end.join}
           }
         SCSS
         options.merge! :filename => name, :syntax => :scss, :importer => self

spec/sprites_spec.rb

@@ -1,5 +1,6 @@
 require File.expand_path(File.dirname(__FILE__) + '/spec_helper')
 require "compass/sprites"
+require 'digest/md5'
 
 describe Compass::Sprites do
   
@@ -20,6 +21,12 @@ describe Compass::Sprites do
     IO.read(File.join(@images_tmp_path, file))[0x10..0x18].unpack('NN')
   end
 
+  def image_md5(file)
+    md5 = Digest::MD5.new
+    md5.update IO.read(File.join(@images_tmp_path, file))
+    md5.hexdigest
+  end
+  
   def render(scss)
     scss = %Q(@import "compass"; #{scss})
     options = Compass.sass_engine_options
@@ -53,6 +60,7 @@ describe Compass::Sprites do
       }
     CSS
     image_size('squares.png').should == [20, 30]
+    image_md5('squares.png').should == 'ac68084abb8f43794a75c5fb28bd62fe'
   end
 
   it "should generate sprite classes with dimensions" do
@@ -238,4 +246,80 @@ describe Compass::Sprites do
     image_size('squares.png').should == [20, 52]
   end
   
+  it "should use position adjustments in functions" do
+    css = render <<-SCSS
+      $squares-position: 100%;
+      @import "squares/*.png";
+      
+      .adjusted-percentage {
+        background-position: sprite-position("squares/10x10.png", 100%);
+      }
+      
+      .adjusted-px-1 {
+        background-position: sprite-position("squares/10x10.png", 4px);
+      }
+      
+      .adjusted-px-2 {
+        background-position: sprite-position("squares/20x20.png", -3px, 2px);
+      }
+    SCSS
+    css.should == <<-CSS
+      .squares-sprite {
+        background: url('/squares.png') no-repeat;
+      }
+      
+      .adjusted-percentage {
+        background-position: 100% 0;
+      }
+      
+      .adjusted-px-1 {
+        background-position: -6px 0;
+      }
+      
+      .adjusted-px-2 {
+        background-position: -3px -8px;
+      }
+    CSS
+    image_size('squares.png').should == [20, 30]
+    image_md5('squares.png').should == 'e274a620ff44c14774fa470d0a9020a1'
+  end
+  
+  it "should use position adjustments in mixins" do
+    css = render <<-SCSS
+      $squares-position: 100%;
+      @import "squares/*.png";
+      
+      .adjusted-percentage {
+        @include squares-sprite("10x10", $x: 100%);
+      }
+      
+      .adjusted-px-1 {
+        @include squares-sprite("10x10", $x: 4px);
+      }
+      
+      .adjusted-px-2 {
+        @include squares-sprite("20x20", $x: -3px, $y: 2px);
+      }
+    SCSS
+    css.should == <<-CSS
+      .squares-sprite, .adjusted-percentage, .adjusted-px-1, .adjusted-px-2 {
+        background: url('/squares.png') no-repeat;
+      }
+      
+      .adjusted-percentage {
+        background-position: 100% 0;
+      }
+      
+      .adjusted-px-1 {
+        background-position: -6px 0;
+      }
+      
+      .adjusted-px-2 {
+        background-position: -3px -8px;
+      }
+    CSS
+    image_size('squares.png').should == [20, 30]
+    image_md5('squares.png').should == 'e274a620ff44c14774fa470d0a9020a1'
+  end
+  
 end