使用compass sprite的时候怎么让它不再次生成文件名

我在config.rb贴上这个也不行。

# Make a copy of sprites with a name that has no uniqueness of the hash.
on_sprite_saved do |filename|
if File.exists?(filename)
FileUtils.cp filename, filename.gsub(%r{-s[a-z0-9]{10}\.png$}, '.png')
end
end

# Replace in stylesheets generated references to sprites
# by their counterparts without the hash uniqueness.
on_stylesheet_saved do |filename|
if File.exists?(filename)
css = File.read filename
File.open(filename, 'w+') do |f|
f << css.gsub(%r{-s[a-z0-9]{10}\.png}, '.png')
end
end
end