sale_layout allows you do add page breaks and subtotals to a sale invoice or sales order.

It is important to note that the sale_layout module has changed completely from OpenERP 6.1 to Odoo 8.0 (It did not officially exist in 7.0).

In 6.1 the visual elements (page breaks, subtotals) would be inserted like a line. To achieve that, sale_order_lines had an additional field layout_type. We used this in combination with Aeroo Reports using a parser that would check the layout_type and inserting the corresponding element into the generated OpenOffice-Document.

However 8.0 changes the architecture: you create a Report Layout Category. You can set a page break or subtotal per Category. Odoo then prints each Category on its own and inserts page breaks if configured to do so.

I am not sure yet how to combine that with Aeroo Reports. I will look into creating a custom parser.py that handles the extraction of the category and its formatting options in pyhton but if someone has a more "canonical" way I would be very interested to hear it.