[Someone]

Yes, it is a well-known issue with Linux and Windows :-)

Seriously, you have to pick one: you either deform letter shapes so that they fit the grid better, with the disadvantage that your line breaks change and/or your letter and/or word spacing look awful, or you ignore the grid until the last moment, compute what percentage of each pixel is covered by each 'infinite resolution' graphene, and color them gray accordingly, with the disadvantage that text looks a bit more blurry.

(technically, there is a third way: layout each character of each font at some set of fixed point sizes by hand, so that it fits the grid perfectly. The original Mac used that method; it became infeasible when the LaserWriter shipped)