This add-on enables POS to read and print tare barcodes. We print a barcode tare label to sell loose goods in a Bring Your Own Container (BYOC) scheme.

The BYOC scheme has four steps:
    1. The cashier weighs the container and sticks the tare bar code onto the customer's pot.
    2. The customer takes the desired quantity of the goods s-he wants to buy.
    3. The cashier weighs the filled container and goods, and POS gives the corresponding price.
    4. The cashier scans the tare bar code, and POS removes the container's weight from the latest product of the order.

This add-on adds a news screen to POS to print (web) the tare barcode labels. This add-on enables POS to read a tare barcode. Reading a barcode makes POS adjust the weight of the latest article in the order list. The new weight is equal to the total weight minus the tare weight. The price is updated accordingly to the weight change.

POS home screen is now:
.. image:: ../static/description/POS_with_button.png

The label screen is:
.. image:: ../static/description/null_weight.png

When we read a weight the impression button is enabled
.. image:: ../static/description/ready_to_print.png

A barcode label looks like:
.. image:: ../static/description/label.png

Zoom on the action widget:
.. image:: ../static/description/zoom_action_widget.png