Grease Pencil Canvas Direction

Is there a way from the python API to know which way the grease pencil canvas is facing in world space?

I’m trying to add support for the grease pencil for render addon. I’ve gotten OK results so far. However, one issue I’m running into is that there are strokes in the layer that are coplanar. This leads to results where parts of one stroke or the other will appear. Here’s an image with the Suzanne example (you can see the problem in the eyes).

I’ve sort of worked around the problem with fills by calculating a normal from the triangles and then slightly offsetting the points in the normal direction. Unfortunately, this won’t work with a regular stroke since there’s no triangles to calculate a normal from. So I’m wondering if there’s a way to know which way the canvas is facing and offset the points with that?