CSS3 gradients with CSSTidy

Gradients are one of the new cool stuff CSS3 brought with it. Like the others cool things, it still suffer from a partial implementation and vendor-specific properties.

It also isn't correctly parsed by CSSTidy. Here I'll show you how to patch your CSSTidy to make it eat gradients correctly.

Quick and dirty patch

First, you'll need to edit the huge parse() method in csstidy.php. You'll have to add a condition to explictly tell CSSTidy not to discard -webkit- gradient and -moz-linear-gradient.

Just open your csstidy.php file, find the parse() method and locate the case 'instr' in the huge switch statement.

if (!($this->str_char === ')' && in_array($string{$i}, $GLOBALS['csstidy']['whitespace']) && !$this->str_in_str)) {
  $this->cur_string .= $temp_add;
} else { // the whole else block is new
    if ($this->sub_value=="-webkit-gradient" || $this->sub_value=="-moz-linear-gradient") {
        $this->cur_string.=' ';
    }
}

The else part is the one to add. This will make sure your webkit and firefox gradient rules will get processed correctly.

I don't really understand WHY it work, but it does. The parse() method is a huge uncommented mess, it is quite difficult to understand it. There must be a better way, a more generic one than specifying some properties, but I didn't manage to come with anything better than that.

Fortunatly, the next part is cleaner.

Telling CSSTidy which properties not to merge

If you write a css like the following, only the latest (color:white) rule will get through CSSTidy.

body {
  color:red;
  color:white;
}

That's logical, because CSSTidy will remove any unused CSS declaration. Unfortunatly, this is not what we want, because we need to declare several background: rules, one for Webkit, and one for Firefox.

By looking at CSSTidy source code, we can find that it contain a quick fix to allow the cursor: property to be defined several time (to cope with the old cursor:pointer / cursor:hand issue).

I just extended this quick fix to work for other properties as well, and even managed to allow them to be passed as a config value.

Defining the config value

First, open the csstidy.php file, and around line 310 you should find a list of default config values. Just add the following:

$this->settings['multiple_properties'] = array('cursor', 'background');

This will define the default list of properties that are allowed to be defined several times in a css rule.

Next, we'll edit the set_cfg() method to allow the passing of array values. Just replace the else statement with this one:

else if(isset($this->settings[$setting]) && $value !== '') {
  // Merging array settings
  if (is_array($value) && is_array($this->settings[$setting])) {
    $this->settings[$setting] = array_merge($this->settings[$setting], $value);
  } else {
    // Setting classic setting
  $this->settings[$setting] = $value;
  }

  if ($setting === 'template') {
    $this->_load_template($this->settings['template']);
  }
  return true;
}

You can now pass a list of properties to be added to the existing list by calling ->set_cfg('multiple_properties', array('property1', 'property2'));

Now, find the css_add_property() method, and around line 1066, change theif (strtolower($property) == 'cursor')if statement to this more generic one :

if (in_array($property, $this->get_cfg('multiple_properties')))

And now, in csstidy_print.php, find the _print() method, and replace the case PROPERTY block with this (more concise) one:

case PROPERTY:
  // Converting back multiple properties
  $multipleProperties = $this->parser->get_cfg('multiple_properties');
  foreach($multipleProperties as $property) {
    $propertyLength = strlen($property);
    if (substr($token[1], 0, $propertyLength)==$property) $token[1] = $property;
  }


  // Applying correct casing
  $caseProperties = $this->parser->get_cfg('case_properties');
  if ($caseProperties==2) $token[1] = strtoupper($token[1]);
  if ($caseProperties==1) $token[1] = strtolower($token[1]);

  $out .= $template[4] . $this->_htmlsp($token[1], $plain) . ':' . $template[5];
break;

And that's it

You now can have gradients compressed with CSSTidy. Well sort of, because this is just a quick and dirty patch, as I'm not the creator of CSSTidy.

This could surely be improved in a less hacky way, for example by compressing the color code used in the gradients...