Text_Diff_Renderer::_block

    function _block($xbeg, $xlen, $ybeg, $ylen, &$edits)
    {
        $output = $this->_startBlock($this->_blockHeader($xbeg, $xlen, $ybeg, $ylen));

        foreach ($edits as $edit) {
            switch (strtolower(get_class($edit))) {
            case 'text_diff_op_copy':
                $output .= $this->_context($edit->orig);
                break;

            case 'text_diff_op_add':
                $output .= $this->_added($edit->final);
                break;

            case 'text_diff_op_delete':
                $output .= $this->_deleted($edit->orig);
                break;

            case 'text_diff_op_change':
                $output .= $this->_changed($edit->orig, $edit->final);
                break;
            }
        }

        return $output . $this->_endBlock();
    }