Winding Style Parameter
The Winding Style parameter is available in these layers:
It determines the way in which Synfig decides whether a point is 'inside' or 'outside' which coloring the layer in.
The Winding Style parameter has two possible values:
- Non Zero
- Even/Odd
The easiest way to see the distinction is to draw a region which contains a loop inside itself:
The top two images have their region winding styles set to "Non Zero" and the bottom two have their region winding styles set to "Even/Odd". "Even/Odd" makes the region see-through when it crosses itself.
The left two images have their outline winding styles set to "Non Zero" and the right two have their outline winding styles set to "Even/Odd". "Even/Odd" makes the outline see-through when it crosses itself.
http://dooglus.rincevent.net/synfig/regions.html has notes I made while investigating how region filling works, and describes the Winding Style parameter.
