Magento AdminHTML Invoice PDF – Draw Table for Purchased Item

In the same file the Mage_Sales_Model_Order_Pdf_Abstract::insertOrder method is what draws the header part of the PDF. To change gray background to white, change:

$page->setFillColor(new Zend_Pdf_Color_GrayScale(0.45));

to

$page->setFillColor(new Zend_Pdf_Color_GrayScale(1));

before the line

$page->drawRectangle(25, $top, 570, $top - 55);

To change color to black in the same file change:

$page->setFillColor(new Zend_Pdf_Color_GrayScale(1));

to

$page->setFillColor(new Zend_Pdf_Color_GrayScale(0));

right after drawRectangle call.

You will have to do the same in Mage_Sales_Model_Order_Pdf_Abstract::insertDocumentNumber() because that is where Invoice # is added.

With all of the above said, you are better off with doing local module which overrides the abstract class or the invoice class. And in it just change what you need. This way in case of future changes in the Abstract.php file in core code pool you will inherit new features and retain your changes as well.

You can customize the invoice layout by modifying this file : Mage_Sales_Model_Order_Pdf_Invoice(app/code/core/Mage/Sales/Model/Order/Pdf/Invoice.php). Of course you need to rewrite the file properly.

Also take a look at these articles for additional info and examples:

1. http://www.atwix.com/magento/customize-magento-pdf-invoice-and-packingslip/
2. http://www.satollo.net/magento-how-to-sligtly-modify-the-invoice-pdf
3. http://www.magentocommerce.com/knowledge-base/entry/custom-pdf-templates/
4. http://www.magentocommerce.com/wiki/5_-_modules_and_development/orders/editing_an_invoice_pdf