static void bufferPolygons(GeoShape shape, double b, out GeoPartList output)
{
foreach (GeoPointList i in shape.getParts())
{
GeoPointList part = i;
if (part.Count < 3)
{
continue;
}
GeoPointList new_part;
// first build the buffered line segments:
SegmentList segments;
foreach (GeoPoint j in part)
{
Vector3D p0 = j;
Vector3D p1 = (j + 1) != part.end() ? *(j + 1) : *part.begin();
Vector3D d = p1 - p0;
d.Normalize();
Vector3D b0 = new Vector3D(p0.X + b * d.Y, p0.Y - b * d.X, p1.z());
Vector3D b1 = new Vector3D(p1.X + b * d.Y, p1.Y - b * d.X, p1.z());
segments.Add(new Segment(b0, b1));
}
// then intersect each pair of segments to find the new verts:
foreach (Segment k in segments)
{
Segment s0 = k;
Segment s1 = (k + 1) != segments.end() ? *(k + 1) : *segments.begin();
Vector3D isect;
if (getLineIntersection(s0, s1, isect))
{
GeoPoint r = new GeoPoint(isect, part[0].getSRS());
r.setDim(part[0].getDim());
new_part.Add(r);
}
}
if (new_part.Count > 2)
{
output.Add(new_part);
}
}
}
// ensures that all single-part shapes have their verts wound CCW.
static Feature wind(Feature input)
{
#if TODO
if (input.getShapeType() == GeoShape.ShapeType.TYPE_POLYGON)
{
foreach (GeoShape i in input.getShapes())
{
GeoShape shape = i;
if (shape.getPartCount() == 1)
{
GeoPointList part = shape.getPart(0);
GeomUtils.openPolygon(part);
if (!GeomUtils.isPolygonCCW(part))
{
std.reverse(part.begin(), part.end());
}
}
}
}
return(input);
#endif
throw new NotImplementedException();
}
