Where starts an ellipse?

Hi all,

I want to work on bug 121305. I know already, that I have to replace 
EnhancedCustomShape2d#1691-1725 with a solution with more segments. My 
idea is to use a 12-segment solution from basegfx. That works in 
principle as I have tested already.

My question is, where the ellipse should start. For a solid stroke it 
makes no difference, but if you use e.g. a dash-dash-dot stroke, you get 
different solutions.

Currently we have:
primitive (legacy) ellipse: start at 6 o'clock.
custom shape ellipse: start at 12 o'clock.
primitive (legacy) rounded rectangle: start at 3 o'clock
import from PowerPoint 365: start at 9 o'clock
import from Inkscape: start at 3 o'clock

The method basegfx::utils::createPolygonFromEllipse would generate a 
start a 3 o'clock. But it would be no problem to use a solution with 6, 
9, or 12 o'clock.

Which start do you want me to use?

Kind regards
Regina