Thanks for that. I recompiled 1.12.2 with the fix, then switched back to SNA. Now I got something different from both previous ones
Looks sharp though, so I'll stick with it.
Cairo asks for Imprecise rendering by default, so the driver is allowed to take a few shortcuts and avoid the overhead of enforcing an 15x17 sampling grid for trapezoidal rasterisation, but still has to obey various rules to ensure that rendering a set of trapezoids is still deterministic. Hopefully I have chosen a good compromise between speed and quality, it should still be higher quality than using skia for example ;-)