def perform
relative_uri = options[:uri].gsub(/^#{Compass.configuration.images_dir}\//, '')
sprites = Compass::SpriteImporter.new(:uri => relative_uri, :options => Compass.sass_engine_options)
options[:output_file] ||= File.join(Compass.configuration.sass_path, "sprites", "_#{sprites.name}.#{Compass.configuration.preferred_syntax}")
options[:skip_overrides] ||= false
contents = sprites.content_for_images(options[:skip_overrides])
if options[:output_file][-4..-1] != "scss"
contents = Sass::Engine.new(contents, Compass.sass_engine_options.merge(:syntax => :scss)).to_tree.to_sass
end
directory File.dirname(options[:output_file])
write_file options[:output_file], contents
end