Compute the area of a layer inside a PCell instance from the callback

Hi everyone,

During the development of my latest PCell, I came across a problem when trying to compute the area of one of my layers in the design.
I want to be able to compute the total area of one layer, let's call it cap_1 in order to update a field in my CDF.
This layer can be holed so i thought about getting the point list of the polygons and add them up but i can't seem to find a way of getting access to my instance from the callback.

Surely using the "Tools" menu and "Area and Density Calculator" from Layout XL does give me the area but i want it to be computed automatically.
Is there a way of running this tool using a skill function ?
I already have the code to compute the area i just need to access the layer data in order to compute it.

Thank you