yf_diff class

    public function custom_style()
    {
        return '<style>' . PHP_EOL .
        '.Differences .ChangeReplace .Left {text-decoration: none;background-color: #f2dede;}' . PHP_EOL .
        '.Differences .ChangeReplace .Right {text-decoration: none;background-color: #dff0d8;}' . PHP_EOL .
        '.Differences ins, .Differences del {text-decoration: none;font-weight: bold;}' . PHP_EOL .
        '</style>' . PHP_EOL;
    }

    public function get_diff($str1, $str2, $type = 'side_by_side')
    {
        $type = isset($this->diff_types[$type]) ? $this->diff_types[$type] : current($this->diff_types);

        // Options for generating the diff
        $options = [
            //'context' => 300,
            //'ignoreNewLines' => true,
            //'ignoreWhitespace' => true,
            //'ignoreCase' => true,
        ];

        //Prepare content
        $str1 = explode("\n", $str1);
        $str2 = explode("\n", $str2);

        // Initialize the diff class
        $diff = new Diff($str1, $str2, $options);

        $diff_type_class = 'Diff_Renderer_Html_' . $type;
        $renderer = new $diff_type_class();
        return $this->custom_style() . $diff->Render($renderer);
    }

    public function __construct()
    {
        require_php_lib('php_diff');

        $this->diff_types = [
            'side_by_side' => 'SideBySide',
            'inline' => 'Inline',
            'unified' => 'Unified',
            'context' => 'Context',
        ];
    }