The messages are from libart. (art_svp_intersect.c, function
art_svp_intersect_add_horiz).
Thank you for your answer. I don't understand why this occurs. Have
you had any issue with that before ?
Yes, I had this message at once, probably about two years ago, but I do
not remember what was the cause.
these messages are caused by giving libart_lgpl a set of points for a
shape that either:
1) have multiple instances of the same x-coordinate values
2) if they wrap around to form a closed polygon (or even
"start" to do so to form a non-closed polygon), they
do not wrap counter-clockwise (IIRC)
--p
I found out I get more or less of those warnings when I play with the
zoom of the canvas. As I draw many polygons, I suppose that conversion
outputs the same x coordinate when points are too close. 