[BUG] Holes in Polygons do not always appear

[JaffaKetchup]

What is the bug?

The points of holes in Polygons must be specified in a winding direction opposite to the winding direction used to specify the normal points - otherwise, a hole is not cut.

The bug was introduced in #1901.

How can we reproduce it?

Reverse the order of the inner hole points in the example application.

Do you have a potential solution?

Using proper Path.combine techniques in the painter appears to fix the issue:

filledPath = Path.combine(
	PathOperation.xor,
	filledPath,
	Path()..addPolygon(holeOffsets, true),
);

However, this is not supported on the Web HTML backend: flutter/flutter#44572.

Instead, the following line works, but was inadvertantely removed and the introduced bug was not found in testing:

filledPath.fillType = PathFillType.evenOdd;

Platforms

All

Severity

Obtrusive: Prevents normal functioning but causes no errors in the console