public static CompiledDrawing FromFace(FillFace face)
{
var fill = new CompiledDrawing();
// Simplify the face by subdividing overlapping curves
var newFace = face.SubdivideOverlapping();
// Build the fill polygons and triangulate them
fill.Triangles = Triangulator.YMonotone.Triangulate(newFace.Contours.Select(FillPolygon).ToArray());
// Collect all curve triangles
var curves = newFace.Contours.SelectMany(v => v.Where(c => c.Type != CurveType.Line)).ToArray();
var curveTriangles = new List <CurveTriangle>();
var doubleCurveTriangles = new List <DoubleCurveTriangle>();
if (curves.Length > 0)
{
// Check first if the last and first curve aren't joinable
bool lastFirstJoin = curves.Length > 1 && FillFace.AreCurvesFusable(curves[curves.Length - 1], curves[0]);
if (lastFirstJoin)
{
doubleCurveTriangles.AddRange(FuseCurveTriangles(curves[curves.Length - 1], curves[0]));
}
else
{
curveTriangles.AddRange(CurveVertex.MakeTriangleFan(curves[0].CurveVertices));
}
// Now, scan the curve list for pairs of scannable curves
var k = lastFirstJoin ? 1 : 0;
for (int i = k; i < curves.Length - k; i++)
{
if (i < curves.Length - 1 && FillFace.AreCurvesFusable(curves[i], curves[i + 1]))
{
doubleCurveTriangles.AddRange(FuseCurveTriangles(curves[i], curves[i + 1]));
i++;
}
else
{
curveTriangles.AddRange(CurveVertex.MakeTriangleFan(curves[i].CurveVertices));
}
}
}
fill.CurveTriangles = curveTriangles.ToArray();
fill.DoubleCurveTriangles = doubleCurveTriangles.ToArray();
return(fill);
}
private static Double2[] FillPolygon(Curve[] contour)
{
// "Guess" a capacity for the list, add the first point
var list = new List <Double2>((int)(1.4 * contour.Length));
// Check first if the last and first curve aren't joinable
bool lastFirstJoin = FillFace.AreCurvesFusable(contour[contour.Length - 1], contour[0]);
if (lastFirstJoin)
{
list.Add(contour[0].At(1));
}
// Now, scan the curve list for pairs of scannable curves
var k = lastFirstJoin ? 1 : 0;
for (int i = k; i < contour.Length - k; i++)
{
if (i < contour.Length - 1 && FillFace.AreCurvesFusable(contour[i], contour[i + 1]))
{
// If they describe a positive winding on the plane, add only its endpoint
var endp0 = contour[i].At(0);
var endp1 = contour[i + 1].At(1);
var pth = (endp0 + endp1) / 2;
if (contour[i].WindingRelativeTo(pth) + contour[i + 1].WindingRelativeTo(pth) > 0)
{
list.Add(endp1);
}
else
{
// Else, compute the convex hull and add the correct point sequence
var points = contour[i].EnclosingPolygon.Concat(contour[i + 1].EnclosingPolygon).ToArray();
var hull = GeometricUtils.ConvexHull(points);
var hl = hull.Length;
// We have to go through the hull clockwise. Find the first point
int ik;
for (ik = 0; ik < hl; ik++)
{
if (hull[ik] == endp0)
{
break;
}
}
// And run through it
for (int i0 = ik; i0 != (ik + 1) % hl; i0 = (i0 + hl - 1) % hl)
{
list.Add(hull[i0]);
}
}
i++;
}
else if (contour[i].Type == CurveType.Line || contour[i].IsConvex)
{
list.Add(contour[i].At(1));
}
else
{
list.AddRange(contour[i].EnclosingPolygon.Skip(1));
}
}
// Sanitize the list; identical vertices
var indices = new List <int>();
for (int i = 0; i < list.Count; i++)
{
if (DoubleUtils.RoughlyEquals(list[i], list[(i + 1) % list.Count]))
{
indices.Add(i);
}
}
list.ExtractIndices(indices.ToArray());
return(list.ToArray());
}