Changes the grid offset to relative or absolute x_offs and y_offs. For non-zero values always use units, e.g. SetGrifOffs(0.5mm, 0.1mm).

The final grid offset alues will be scaled down so they are always between 0 and the current grid size. For example with a 25 mil grid, a value of 7mil will be taken as 7mil offset, but a value of 27 mil will be taken as a 2mil offset.

If an offset starts with + or -, it is taken as relative, which means it is added to the current offset value.