sprite module files

lib/compass/sass_extensions/sprites/image_methods.rb

@@ -0,0 +1,32 @@
+module Compass
+  module SassExtensions
+    module Sprites
+      module ImageMethods
+        # Fetches the Sprite::Image object for the supplied name
+         def image_for(name)
+           @images.detect { |img| img.name == name}
+         end
+
+         # Returns true if the image name has a hover selector image
+         def has_hover?(name)
+           !image_for("#{name}_hover").nil?
+         end
+
+         # Returns true if the image name has a target selector image
+         def has_target?(name)
+           !image_for("#{name}_target").nil?
+         end
+
+         # Returns true if the image name has an active selector image
+         def has_active?(name)
+           !image_for("#{name}_active").nil?
+         end
+
+         # Return and array of image names that make up this sprite
+         def sprite_names
+           image_names.map { |f| File.basename(f, '.png') }
+         end
+      end
+    end
+  end
+end

lib/compass/sass_extensions/sprites/sprite_methods.rb

@@ -0,0 +1,126 @@
+module Compass
+  module SassExtensions
+    module Sprites
+      module SpriteMethods
+        
+        # Changing this string will invalidate all previously generated sprite images.
+        # We should do so only when the packing algorithm changes
+        SPRITE_VERSION = "1"
+        
+        # Calculates the overal image dimensions
+        # collects image sizes and input parameters for each sprite
+        # Calculates the height
+        def compute_image_metadata!
+          @width = 0
+          init_images
+          compute_image_positions!
+          @height = @images.last.top + @images.last.height
+        end
+        
+        # Creates the Sprite::Image objects for each image and calculates the width
+        def init_images
+          @images = image_names.collect do |relative_file|
+            image = Compass::SassExtensions::Sprites::Image.new(self, relative_file, kwargs)
+            @width = [ @width, image.width + image.offset ].max
+            image
+          end
+        end
+        
+        # Calculates the overal image dimensions
+        # collects image sizes and input parameters for each sprite
+        def compute_image_positions!
+          @images.each_with_index do |image, index|
+            image.left = image.position.unit_str == "%" ? (@width - image.width) * (image.position.value / 100) : image.position.value
+            next if index == 0
+            last_image = @images[index-1]
+            image.top = last_image.top + last_image.height + [image.spacing,  last_image.spacing].max
+          end
+        end
+        
+        # Validates that the sprite_names are valid sass
+        def validate!
+          for sprite_name in sprite_names
+            unless sprite_name =~ /\A#{Sass::SCSS::RX::IDENT}\Z/
+              raise Sass::SyntaxError, "#{sprite_name} must be a legal css identifier"
+            end
+          end
+        end
+
+        # The on-the-disk filename of the sprite
+        def filename
+          File.join(Compass.configuration.images_path, "#{path}-s#{uniqueness_hash}.png")
+        end
+
+        # Generate a sprite image if necessary
+        def generate
+          if generation_required?
+            if kwargs.get_var('cleanup').value
+              cleanup_old_sprites
+            end
+            sprite_data = construct_sprite
+            save!(sprite_data)
+            Compass.configuration.run_callback(:sprite_generated, sprite_data)
+          end
+        end
+        
+        def cleanup_old_sprites
+          Dir[File.join(Compass.configuration.images_path, "#{path}-*.png")].each do |file|
+            FileUtils.rm file
+          end
+        end
+        
+        # Does this sprite need to be generated
+        def generation_required?
+          !File.exists?(filename) || outdated?
+        end
+
+        # Returns the uniqueness hash for this sprite object
+        def uniqueness_hash
+          @uniqueness_hash ||= begin
+            sum = Digest::MD5.new
+            sum << SPRITE_VERSION
+            sum << path
+            images.each do |image|
+              [:relative_file, :height, :width, :repeat, :spacing, :position, :digest].each do |attr|
+                sum << image.send(attr).to_s
+              end
+            end
+            sum.hexdigest[0...10]
+          end
+          @uniqueness_hash
+        end
+
+        # Saves the sprite engine
+        def save!(output_png)
+          saved = output_png.save filename
+          Compass.configuration.run_callback(:sprite_saved, filename)
+          saved
+        end
+
+        # All the full-path filenames involved in this sprite
+        def image_filenames
+          @images.map(&:file)
+        end
+
+        # Checks whether this sprite is outdated
+        def outdated?
+          if File.exists?(filename)
+            return @images.map(&:mtime).any? { |imtime| imtime.to_i > self.mtime.to_i }
+          end
+          true
+        end
+
+        # Mtime of the sprite file
+        def mtime
+          @mtime ||= File.mtime(filename)
+        end
+        
+       # Calculate the size of the sprite
+        def size
+          [width, height]
+        end
+
+      end
+    end
+  end
+end