Matrix Orbital Corp

My display is GLK24064. I want to calculate the absolute pixel position of a character. Are the font metrics values based on 0 or 1? In other words, is the leftmost pixel of Left Margin 0 or is it 1. And is 0 a valid value? Thanks, Vernon.

The coordinates are 1 based. 0 is invalid. While this isn't the "normal" convention, it was carried over from the alpha-numeric display where the upper left was row 1 column 1.