CodingForums.com - function to split a description into lines of 68 chars long

Im just wondering if anyone can help me out. Iv been trying to figure this out all day.
I have these variables

PHP Code:


		
			
$booking['occasion']
$booking['date']
$booking['venue']

and I want to make a description out of them like this.

$description = "Deposit for supplying a DJ for an $occasion on the
$date in the $venue";

I want to display the description over 3 or 4 lines in a pdf file like this

PHP Code:


		
			
$pdf->writeHTMLCell(139, 5, '20', '125', $line1, '', 1, 1, true, 'L', true);
$pdf->writeHTMLCell(139, 5, '25', '125', $line2, '', 1, 1, true, 'L', true);
$pdf->writeHTMLCell(139, 5, '30', '125', $line3, '', 1, 1, true, 'L', true);
$pdf->writeHTMLCell(139, 5, '35', '125', $line4, '', 1, 1, true, 'L', true);
$pdf->writeHTMLCell(139, 5, '40', '125', $line5, '', 1, 1, true, 'L', true);

I want to wrap the description to a next line after every 68 characters but only want to wrap after completed words

Can anyone help me create a function to split the desicprtion into 3 or 4 lines so far I have this code which I know is along the lines that I want.

PHP Code:


		
			
$description = "Deposit for suppling a DJ and Equipment for a $occasion on the 
$date in $venue";
$decriptionLength = strlen($description);
if($decriptionLength <= 68){
    $line1 = $description;    
}
elseif($decriptionLength > 68)
{
    $line1 = substr($description, 0, 68);
    $line2 = substr($description, 68, 136);
}

This code will wrap the text even in the middle of a word so I don’t want this.
I know this might be a lot to ask but if anyone can come up with some code I would be greatly appreciated.