[php] Truncating Text in PHP?

I'm trying to truncate some text in PHP and have stumbled across this method (http://theodin.co.uk/blog/development/truncate-text-in-php-the-easy-way.html), which judging by the comments seems like a great easy-to-implement solution. The problem is I don't know how to implement it :S.

Would someone mind pointing me in the direction of what to do to implement this? Any help whatsoever would be appreciated.

Thanks in advance.

$text="abc1234567890";

// truncate to 4 chars

echo substr(str_pad($text,4),0,4);

This avoids the problem of truncating a 4 char string to 10 chars .. (i.e. source is smaller than the required)

$mystring = "this is the text I would like to truncate";

// Pass your variable to the function
$mystring = truncate($mystring);

// Truncated tring printed out;
echo $mystring;

//truncate text function
public function truncate($text) {

    //specify number fo characters to shorten by
    $chars = 25;

    $text = $text." ";
    $text = substr($text,0,$chars);
    $text = substr($text,0,strrpos($text,' '));
    $text = $text."...";
    return $text;
}