Excellent work. I'll add some integration tests so that we can look visually to confirm that everything is working as expected.

Coverage increased (+0.02%) to 69.244% when pulling 54fba8a on vicencb:master into e7c1175 on pcb2gcode:master.

I see a little bit of confusion around positive and negative. In KiCad, positive x is to the right and positive y is downward. But in gerbv, positive x is to the right and positive y is upward.

Since we're using gerbv as a library, I think that we'll do it the gerbv way. Also it makes the code make more sense so that the handling of x and the handling of y look similar.

Here's my test image:

If I set the axis to be y and the mirror-axis to be -0.5inches, those little marks on the right side line up properly, so that seems great!

I also checked that it works with the tiling features enabled. Great!

The tests should improve coverage.

Hi Eyal,
thank you for adding tests, improving coverage and merging it.
Are you able to merge this one too ?

Regards,
Vicente.