Magento – magento: invoice PDF design customization

Change the file Mage_Sales_Model_Order_Pdf_Items_Invoice_Default which is in

 app/code/core/Mage/Sales/Model/Order/Pdf/Items/Invoice

First of all, copying files that can just be overridden from the Core to Local is not best practise as it can possibly give you more work when upgrading Magento.

I have tested your case and found your solution:

First of all I rewrite it in my own extension:

 <models>
            <sales>
                <rewrite><order_pdf_items_invoice_default>MycompanyName_Myextensionname_Model_Order_Pdf_Items_Invoice_Default</order_pdf_items_invoice_default></rewrite>
            </sales>
 </models>

Then I override the function you mentioned above:

 $options = $this->getItemOptions();
    if ($options) {
        foreach ($options as $option) {
            if ($option['value']) {
                if (isset($option['print_value'])) {
                    $_printValue = $option['print_value'];
                } else {
                    $_printValue = strip_tags($option['value']);
                }
                $values = explode(', ', $_printValue);
                foreach ($values as $value) {
                    $lines[][] = array(
                        'text' => Mage::helper('core/string')->str_split(strip_tags($option['label'] . " - " . $value), 40, true, true),
                        'feed' => 40
                    );
                }
            }
        }
    }

What I have done here is just removed the part where you draw the label and added it to the part where you print the value.

If you have long labels/values and you want to keep it on one line, I would increase the value in str_split.