/**
  * Draw a line of text at the specified position.
  *
  * @param string $text
  * @param float $x
  * @param float $y
  * @param string $charEncoding (optional) Character encoding of source text.
  *   Defaults to current locale.
  * @throws Zend_Pdf_Exception
  * @return Zend_Pdf_Canvas_Interface
  */
 public function drawText($text, $x, $y, $charEncoding = '')
 {
     if ($this->_font === null) {
         require_once 'Zend/Pdf/Exception.php';
         throw new Zend_Pdf_Exception('Font has not been set');
     }
     $this->_addProcSet('Text');
     $textObj = new Zend_Pdf_Element_String($this->_font->encodeString($text, $charEncoding));
     $xObj = new Zend_Pdf_Element_Numeric($x);
     $yObj = new Zend_Pdf_Element_Numeric($y);
     $this->_contents .= "BT\n" . $xObj->toString() . ' ' . $yObj->toString() . " Td\n" . $textObj->toString() . " Tj\n" . "ET\n";
     return $this;
 }