Allowed extensions

doc-src/content/help/tutorials/extending.markdown

@@ -14,6 +14,8 @@ The sprite engine is the work horse of sprite generation it's the interface for
 
 ### Requirements
 
+A sprite engine requires a constant be defined called `VALID_EXTENSIONS` that returns and array of valid image extensions ex. `['.png', '.jpg']`
+
 A sprite engine requires two methods `construct_sprite`, and `save(filename)`
 
 Once inside the class you have access to `images` which is a collection of [Compass::SassExtensions::Sprites::Image](http://rdoc.info/github/chriseppstein/compass/dda7c9/Compass/SassExtensions/Sprites/Image)

lib/compass/sass_extensions.rb

@@ -2,7 +2,9 @@
   raise LoadError, "It looks like you've got an incompatible version of Sass. This often happens when you have an old haml gem installed. Please upgrade Haml to v3.1 or above."
 end
 
-module Compass::SassExtensions
+module Compass
+  module SassExtensions
+  end
 end
 
 require 'compass/sass_extensions/functions'

lib/compass/sass_extensions/sprites.rb

@@ -1,13 +1,11 @@
-require 'digest/md5'
-require 'compass/sprite_importer'
-
 module Compass
   module SassExtensions
     module Sprites
     end
   end
 end
 
+require 'digest/md5'
 require 'compass/sass_extensions/sprites/images'
 require 'compass/sass_extensions/sprites/layout'
 require 'compass/sass_extensions/sprites/image_row'
@@ -18,4 +16,5 @@ module Sprites
 require 'compass/sass_extensions/sprites/image_methods'
 require 'compass/sass_extensions/sprites/sprite_map'
 require 'compass/sass_extensions/sprites/engines'
+require 'compass/sprite_importer'
 

lib/compass/sass_extensions/sprites/engines.rb

@@ -1,9 +1,10 @@
+
 module Compass
   module SassExtensions
     module Sprites
       class Engine
         attr_accessor :width, :height, :images, :canvas
-        def initialize(width, height, images)
+        def initialize(width=nil, height=nil, images=nil)
           @width, @height, @images = width, height, images
           @canvas = nil
         end
@@ -21,5 +22,4 @@ def save(filename)
   end
 end
 
-
-require 'compass/sass_extensions/sprites/engines/chunky_png_engine'
+require 'compass/sass_extensions/sprites/engines/chunky_png_engine'

lib/compass/sass_extensions/sprites/engines/chunky_png_engine.rb

@@ -9,6 +9,8 @@ module SassExtensions
     module Sprites
       class ChunkyPngEngine < Compass::SassExtensions::Sprites::Engine
 
+        VALID_EXTENSIONS = ['.png']
+
         def construct_sprite
           @canvas = ChunkyPNG::Image.new(width, height, ChunkyPNG::Color::TRANSPARENT)
           images.each do |image|

lib/compass/sass_extensions/sprites/sprite_map.rb

@@ -32,6 +32,10 @@ def self.relative_name(sprite)
           end
         end
 
+        def self.sprite_engine_class      
+          constantize("Compass::SassExtensions::Sprites::#{self.modulize}Engine")
+        end
+
         def initialize(sprites, path, name, context, kwargs)
           @image_names = sprites
           @path = path
@@ -81,10 +85,23 @@ def method_missing(meth, *args, &block)
 
         private 
 
-        def modulize
+        def self.modulize
           @modulize ||= Compass::configuration.sprite_engine.to_s.scan(/([^_.]+)/).flatten.map {|chunk| "#{chunk[0].chr.upcase}#{chunk[1..-1]}" }.join
         end
 
+        def self.constantize(camel_cased_word)
+          names = camel_cased_word.split('::')
+          names.shift if names.empty? || names.first.empty?
+
+          constant = Object
+          names.each do |name|
+            constant = constant.const_defined?(name) ? constant.const_get(name) : constant.const_missing(name)
+          end
+          constant
+        end
+
+
+
       end
     end
   end

lib/compass/sass_extensions/sprites/sprite_methods.rb

@@ -18,7 +18,7 @@ def compute_image_metadata!
         end
 
         def init_engine
-          @engine = eval("::Compass::SassExtensions::Sprites::#{modulize}Engine.new(nil, nil, nil)")
+          @engine = self.class.sprite_engine_class.new
           @engine.width = @width
           @engine.height = @height
           @engine.images = @images

lib/compass/sprite_importer.rb

@@ -1,10 +1,14 @@
 require 'erb'
+require 'compass'
 require 'compass/sprite_importer/binding'
+
+
+
+
 module Compass
   class SpriteImporter < Sass::Importers::Base
     VAILD_FILE_NAME       = /\A#{Sass::SCSS::RX::IDENT}\Z/
-    SPRITE_IMPORTER_REGEX = %r{((.+/)?([^\*.]+))/(.+?)\.png}
-    VALID_EXTENSIONS      = ['.png']
+    SPRITE_IMPORTER_REGEX = %r{((.+/)?([^\*.]+))/(.+?)}
 
     TEMPLATE_FOLDER       = File.join(File.expand_path('../', __FILE__), 'sprite_importer')
     CONTENT_TEMPLATE_FILE = File.join(TEMPLATE_FOLDER, 'content.erb')
@@ -15,7 +19,7 @@ class SpriteImporter < Sass::Importers::Base
     # finds all sprite files
     def self.find_all_sprite_map_files(path)
       hex = "[0-9a-f]"
-      glob = "*-s#{hex*10}{#{VALID_EXTENSIONS.join(",")}}"
+      glob = "*-s#{hex*10}{#{valid_extensions.join(",")}}"
       Sass::Util.glob(File.join(path, "**", glob))
     end
 
@@ -53,7 +57,7 @@ def key(uri, options={})
     end
 
     def self.path_and_name(uri)
-      if uri =~ SPRITE_IMPORTER_REGEX
+      if uri =~ sprite_importer_regex_with_ext
         [$1, $3]
       else
         raise Compass::Error, "invalid sprite path"
@@ -107,6 +111,16 @@ def self.content_for_images(uri, name, skip_overrides = false)
       binder = Compass::Sprites::Binding.new(:name => name, :uri => uri, :skip_overrides => skip_overrides, :sprite_names => sprite_names(uri), :files => files(uri))
       CONTENT_TEMPLATE.result(binder.get_binding)
     end
+
+  private
+
+    def self.valid_extensions
+      @valid_extensions ||= SassExtensions::Sprites::SpriteMap.sprite_engine_class::VALID_EXTENSIONS
+    end
+
+    def self.sprite_importer_regex_with_ext
+      @importer_regex ||= %r{#{SPRITE_IMPORTER_REGEX}(#{valid_extensions.join('|')})}
+    end
   end
 end