void
OffsetCurveSetBuilder::addPolygon(const Polygon *p)
{
double offsetDistance=distance;
int offsetSide=Position::LEFT;
if (distance < 0.0) {
offsetDistance=-distance;
offsetSide=Position::RIGHT;
}
const LinearRing *shell=(const LinearRing *)p->getExteriorRing();
CoordinateSequence *shellCoord = CoordinateSequence::removeRepeatedPoints(shell->getCoordinatesRO());
// optimization - don't bother computing buffer
// if the polygon would be completely eroded
if (distance < 0.0 && isErodedCompletely(shellCoord, distance))
{
delete shellCoord;
return;
}
addPolygonRing(shellCoord,offsetDistance,offsetSide,Location::EXTERIOR,Location::INTERIOR);
delete shellCoord;
for (int i=0;i<p->getNumInteriorRing(); i++) {
const LinearRing *hole=(const LinearRing *)p->getInteriorRingN(i);
CoordinateSequence *holeCoord=CoordinateSequence::removeRepeatedPoints(hole->getCoordinatesRO());
// optimization - don't bother computing buffer for this hole
// if the hole would be completely covered
if (distance > 0.0 && isErodedCompletely(holeCoord, -distance))
{
delete holeCoord;
continue;
}
// Holes are topologically labelled opposite to the shell, since
// the interior of the polygon lies on their opposite side
// (on the left, if the hole is oriented CCW)
addPolygonRing(holeCoord,offsetDistance,Position::opposite(offsetSide),Location::INTERIOR,Location::EXTERIOR);
delete holeCoord;
}
}
/*private*/
void
OffsetCurveSetBuilder::addPolygon(const Polygon *p)
{
double offsetDistance=distance;
int offsetSide=Position::LEFT;
if (distance < 0.0)
{
offsetDistance = -distance;
offsetSide = Position::RIGHT;
}
// FIXME: avoid the C-style cast
const LinearRing *shell=(const LinearRing *)p->getExteriorRing();
CoordinateSequence *shellCoord = CoordinateSequence::removeRepeatedPoints(shell->getCoordinatesRO());
// optimization - don't bother computing buffer
// if the polygon would be completely eroded
if (distance < 0.0 && isErodedCompletely(shellCoord, distance))
{
delete shellCoord;
return;
}
// don't attemtp to buffer a polygon
// with too few distinct vertices
if (distance <= 0.0 && shellCoord->size() < 3)
{
delete shellCoord;
return;
}
addPolygonRing(
shellCoord,
offsetDistance,
offsetSide,
Location::EXTERIOR,
Location::INTERIOR);
delete shellCoord;
for (size_t i=0, n=p->getNumInteriorRing(); i<n; ++i)
{
const LineString *hls=p->getInteriorRingN(i);
assert(dynamic_cast<const LinearRing *>(hls));
const LinearRing *hole=static_cast<const LinearRing *>(hls);
CoordinateSequence *holeCoord=CoordinateSequence::removeRepeatedPoints(hole->getCoordinatesRO());
// optimization - don't bother computing buffer for this hole
// if the hole would be completely covered
if (distance > 0.0 && isErodedCompletely(holeCoord, -distance))
{
delete holeCoord;
continue;
}
// Holes are topologically labelled opposite to the shell,
// since the interior of the polygon lies on their opposite
// side (on the left, if the hole is oriented CCW)
addPolygonRing(
holeCoord,
offsetDistance,
Position::opposite(offsetSide),
Location::INTERIOR,
Location::EXTERIOR);
delete holeCoord;
}
}