Totals on Invoice and Credit memo

Question

I see that the totals on PDF invoices, and on credit memo are pulled from one same abstract.php

Can I somehow make different totals on credit memo than on invoice? is there a way to make a copy of abstract.php only for credit memos?

I need to display some negative valuues in front of totals on my credit memo, so thats why I need this.

Answer 1

Although I don't know exactly which classes you are referring to Abstract.php is likely not called directly but extended from a different class. If that's the case I suggest you rewrite the class that is extending Abstract and overwrite the method that is in abstract.

So let's say you have the abstract class

class Mage_Sales_Model_Abstract
{
   public function getTotals()
   {
      [...]
      here the totals come from
      [...]
   }
}

and the credit class

class Mage_Sales_Model_Creditmemo extends Mage_Sales_Model_Abstract
{
   [...]
   the credit memo methods
   [...]           
}

You will need to rewrite the Mage_Sales_Model_Creditmemo class with your own extension. It would look something like this

class [Namespace]_[Module]_Model_Creditmemo extends Mage_Sales_Model_Creditmemo
{
   public function getTotals()
   {
      [...]
      Here is your edited totals function
      [...]
   }
}