private static List <List <Point2d> > clipGeometries(
List <List <Point2d> > geoms
, GeomType geomType
, long extent
, uint bufferSize
)
{
List <List <Point2d> > retVal = new List <List <Point2d> >();
//points: simply remove them if one part of the coordinate pair is out of bounds:
// <0 || >extent
if (geomType == GeomType.POINT)
{
foreach (var geomPart in geoms)
{
List <Point2d> outGeom = new List <Point2d>();
foreach (var geom in geomPart)
{
if (
geom.X < (0L - bufferSize) ||
geom.Y < (0L - bufferSize) ||
geom.X > (extent + bufferSize) ||
geom.Y > (extent + bufferSize)
)
{
continue;
}
outGeom.Add(geom);
}
if (outGeom.Count > 0)
{
retVal.Add(outGeom);
}
}
return(retVal);
}
//use clipper for lines and polygons
bool closed = true;
if (geomType == GeomType.LINESTRING)
{
closed = false;
}
Polygons subjects = new Polygons();
Polygons clip = new Polygons(1);
Polygons solution = new Polygons();
clip.Add(new Polygon(4));
clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, 0L - bufferSize));
clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, 0L - bufferSize));
clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, extent + bufferSize));
clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, extent + bufferSize));
foreach (var geompart in geoms)
{
Polygon part = new Polygon();
foreach (var geom in geompart)
{
part.Add(new InternalClipper.IntPoint(geom.X, geom.Y));
}
subjects.Add(part);
}
InternalClipper.Clipper c = new InternalClipper.Clipper();
c.AddPaths(subjects, InternalClipper.PolyType.ptSubject, closed);
c.AddPaths(clip, InternalClipper.PolyType.ptClip, true);
bool succeeded = false;
if (geomType == GeomType.LINESTRING)
{
InternalClipper.PolyTree lineSolution = new InternalClipper.PolyTree();
succeeded = c.Execute(
InternalClipper.ClipType.ctIntersection
, lineSolution
, InternalClipper.PolyFillType.pftNonZero
, InternalClipper.PolyFillType.pftNonZero
);
if (succeeded)
{
solution = InternalClipper.Clipper.PolyTreeToPaths(lineSolution);
}
}
else
{
succeeded = c.Execute(
InternalClipper.ClipType.ctIntersection
, solution
, InternalClipper.PolyFillType.pftNonZero
, InternalClipper.PolyFillType.pftNonZero
);
}
if (succeeded)
{
retVal = new List <List <Point2d> >();
foreach (var part in solution)
{
List <Point2d> geompart = new List <Point2d>();
foreach (var geom in part)
{
geompart.Add(new Point2d()
{
X = geom.X, Y = geom.Y
});
}
retVal.Add(geompart);
}
return(retVal);
}
else
{
//if clipper was not successfull return original geometries
return(geoms);
}
}
/// <summary>
/// TO BE REMOVED!!! Processing geometries is out of scope.
/// Clip geometries extending beyond the tile border.
/// </summary>
/// <param name="geoms">Raw tile geometries of the feature</param>
/// <param name="geomType">Geometry type of the feature</param>
/// <param name="extent">Extent of the layer </param>
/// <param name="bufferSize">Units (in internal tile coordinates) to go beyond the tile border. Pass '0' to clip exactly at the tile border</param>
/// <param name="scale">Factor for scaling the geometries</param>
/// <returns></returns>
public static List <List <Point2d <long> > > ClipGeometries(
List <List <Point2d <long> > > geoms
, GeomType geomType
, long extent
, uint bufferSize
, float scale
)
{
List <List <Point2d <long> > > retVal = new List <List <Point2d <long> > >();
//points: simply remove them if one part of the coordinate pair is out of bounds:
// <0 || >extent
if (geomType == GeomType.POINT)
{
foreach (var geomPart in geoms)
{
List <Point2d <long> > outGeom = new List <Point2d <long> >();
foreach (var geom in geomPart)
{
if (
geom.X < (0L - bufferSize) ||
geom.Y < (0L - bufferSize) ||
geom.X > (extent + bufferSize) ||
geom.Y > (extent + bufferSize)
)
{
continue;
}
outGeom.Add(geom);
}
if (outGeom.Count > 0)
{
retVal.Add(outGeom);
}
}
return(retVal);
}
//use clipper for lines and polygons
bool closed = true;
if (geomType == GeomType.LINESTRING)
{
closed = false;
}
Polygons subjects = new Polygons();
Polygons clip = new Polygons(1);
Polygons solution = new Polygons();
clip.Add(new Polygon(4));
clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, 0L - bufferSize));
clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, 0L - bufferSize));
clip[0].Add(new InternalClipper.IntPoint(extent + bufferSize, extent + bufferSize));
clip[0].Add(new InternalClipper.IntPoint(0L - bufferSize, extent + bufferSize));
foreach (var geompart in geoms)
{
Polygon part = new Polygon();
foreach (var geom in geompart)
{
part.Add(new InternalClipper.IntPoint(geom.X, geom.Y));
}
subjects.Add(part);
}
InternalClipper.Clipper c = new InternalClipper.Clipper();
c.AddPaths(subjects, InternalClipper.PolyType.ptSubject, closed);
c.AddPaths(clip, InternalClipper.PolyType.ptClip, true);
bool succeeded = false;
if (geomType == GeomType.LINESTRING)
{
InternalClipper.PolyTree lineSolution = new InternalClipper.PolyTree();
succeeded = c.Execute(
InternalClipper.ClipType.ctIntersection
, lineSolution
, InternalClipper.PolyFillType.pftNonZero
, InternalClipper.PolyFillType.pftNonZero
);
if (succeeded)
{
solution = InternalClipper.Clipper.PolyTreeToPaths(lineSolution);
}
}
else
{
succeeded = c.Execute(
InternalClipper.ClipType.ctIntersection
, solution
, InternalClipper.PolyFillType.pftNonZero
, InternalClipper.PolyFillType.pftNonZero
);
}
if (succeeded)
{
retVal = new List <List <Point2d <long> > >();
foreach (var part in solution)
{
List <Point2d <long> > geompart = new List <Point2d <long> >();
// HACK:
// 1. clipper may or may not reverse order of vertices of LineStrings
// 2. clipper semms to drop the first vertex of a Polygon
// * We don't care about 1.
// * Added a check for 2 and insert a copy of last vertex as first
foreach (var geom in part)
{
geompart.Add(new Point2d <long>()
{
X = geom.X, Y = geom.Y
});
}
if (geomType == GeomType.POLYGON)
{
if (!geompart[0].Equals(geompart[geompart.Count - 1]))
{
geompart.Insert(0, geompart[geompart.Count - 1]);
}
}
retVal.Add(geompart);
}
return(retVal);
}
else
{
//if clipper was not successfull return original geometries
return(geoms);
}
}
