Class: YUI::CSS

Inherits:
Object
  • Object
show all
Defined in:
lib/yui/css_compressor.rb

Overview

Methods for working with CSS.

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.input_size ⇒ Object (readonly)

Returns the value of attribute input_size.



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# File 'lib/yui/css_compressor.rb', line 51

def input_size
  @input_size
end

.output_size ⇒ Object (readonly)

Returns the value of attribute output_size.



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# File 'lib/yui/css_compressor.rb', line 51

def output_size
  @output_size
end

Class Method Details

.compress(css, line_length = 0) ⇒ String

Compress CSS using the Ruby port of the YUI Compressor (by <a href=“github.com/rhulse”>Richard Hulse</a>).

Parameters:

  • css (String) —

    The CSS to be compressed.

  • line_length (Integer) (defaults to: 0) —

    (optional) Number of columns to wrap to. Default is no wrapping.

Returns:

  • (String) —

    Compressed CSS.



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# File 'lib/yui/css_compressor.rb', line 62

def compress(css, line_length=0)
  @preservedTokens = []
  @comments = []
  @output_size = 0
  @input_size = css.length
  
  css = process_comments_and_strings(css)
  
  # Normalize all whitespace strings to single spaces. Easier to work with that way.
  css.gsub!(/\s+/, ' ')
  
  # Remove the spaces before the things that should not have spaces before them.
  # But, be careful not to turn "p :link {...}" into "p:link{...}"
  # Swap out any pseudo-class colons with the token, and then swap back.
  css.gsub!(/(?:^|\})[^\{:]+\s+:+[^\{]*\{/) do |match|
    match.gsub(':', '___PSEUDOCLASSCOLON___')
  end
  css.gsub!(/\s+([!\{\};:>+\(\)\],])/, '\1')
  css.gsub!(/([!\{\}:;>+\(\[,])\s+/, '\1')
  css.gsub!('___PSEUDOCLASSCOLON___', ':')
  
  # special case for IE
  css.gsub!(/:first-(line|letter)(\{|,)/, ':first-\1 \2')
  
  # no space after the end of a preserved comment
  css.gsub!(/\*\/ /, '*/')
  
  # If there is a @charset, then only allow one, and push to the top of the file.
  css.gsub!(/^(.*)(@charset "[^"]*";)/i, '\2\1')
  css.gsub!(/^(\s*@charset [^;]+;\s*)+/i, '\1')
  
  # Put the space back in some cases, to support stuff like
  # @media screen and (-webkit-min-device-pixel-ratio:0){
  css.gsub!(/\band\(/i, "and (")
  
  # remove unnecessary semicolons
  css.gsub!(/;+\}/, '}')
  
  # Replace 0(%, em, ex, px, in, cm, mm, pt, pc) with just 0.
  css.gsub!(/([\s:])([+-]?0)(?:%|em|ex|px|in|cm|mm|pt|pc)/i, '\1\2')
  
  # Replace 0 0 0 0; with 0.
  css.gsub!(/:(?:0 )+0(;|\})/, ':0\1')
  
  # Restore background-position:0 0; if required
  css.gsub!(/background-position:0(;|\})/i, 'background-position:0 0\1')
  
  # Replace 0.6 with .6, but only when preceded by : or a space.
  css.gsub!(/(:|\s)0+\.(\d+)/, '\1.\2')
  
  # Shorten colors from rgb(51,102,153) to #336699
  # This makes it more likely that it'll get further compressed in the next step.
  css.gsub!(/rgb\s*\(\s*([0-9,\s]+)\s*\)/) do |match|
    '#' << $1.scan(/\d+/).map{|n| n.to_i.to_s(16).rjust(2, '0') }.join
  end
  
  # Shorten colors from #AABBCC to #ABC. Note that we want to make sure
  # the color is not preceded by either ", " or =. Indeed, the property
  #     filter: chroma(color="#FFFFFF");
  # would become
  #     filter: chroma(color="#FFF");
  # which makes the filter break in IE.
  css.gsub!(/([^"'=\s])(\s?)\s*#([0-9a-f])\3([0-9a-f])\4([0-9a-f])\5/i, '\1\2#\3\4\5')
  
  # shorter opacity IE filter
  css.gsub!(/progid:DXImageTransform\.Microsoft\.Alpha\(Opacity=/i, "alpha(opacity=")
  
  # Remove empty rules.
  css.gsub!(/[^\};\{\/]+\{\}/, '')
  
  if (line_length > 0)
    # Some source control tools don't like it when files containing lines longer
    # than, say 8000 characters, are checked in. The linebreak option is used in
    # that case to split long lines after a specific column.
    startIndex = 0
    index = 0
    length = css.length
    while (index < length)
      index += 1
      if (css[index - 1,1] === '}' && index - startIndex > line_length)
        css = css.slice(0, index) + "\n" + css.slice(index, length)
        startIndex = index
      end
    end
  end
  
  # Replace multiple semi-colons in a row by a single one
  # See SF bug #1980989
  css.gsub!(/[;]+/, ';')
  
  #restore preserved comments and strings
  css = restore_preserved_comments_and_strings(css)
  
  # top and tail whitespace
  css.strip!
  
  @output_size = css.length
  css
end