I largely agree with Dr1 Driver --- except --- the thrust line is not the reference line. The reference is an arbitrary longitudinal line (sometimes the mid-line of the fuse) & all other things are referenced to it. For convenience, the extended plane of the horiz stab is often used as the reference line.

The thrust line can be positive or negative relative to the reference line, as can the chord line of the main plane (wing) & the horiz stab, but that is unusual.

Sounds confusing? It can be -- which is why the horiz stab is a good thing to use as a reference.

BTW it is the chord line of the wing, not the centerline.

Taking the plane of the stab as the reference, if the wing chord-line is tilted up at the leading edge, then the wing has positive incidence. Similarly, if the chord-line is tilted down at the leading edge, the wing has negative incidence.

As noted, the engine can be tilted up or down (and often is) relative to the incidence reference. To further confuse you, it can also be angled right or left & offset right or left relative to the axial centerline of the fuse.