void object::test<1>()
{
using geos::operation::buffer::BufferBuilder;
using geos::operation::buffer::BufferParameters;
using geos::algorithm::CGAlgorithms;
using geos::geom::LineString;
// Original input from test in ticket #633
//std::string wkt0("LINESTRING ("
// "665.7317504882812500 133.0762634277343700,"
// "1774.4752197265625000 19.9391822814941410,"
// "756.2413940429687500 466.8306579589843700,"
// "626.1337890625000000 1898.0147705078125000,"
// "433.8007202148437500 404.6052856445312500)");
//double const distance = 57.164000837203;
// Simplified equivalent input
std::string wkt0("LINESTRING(0 0, 50 -10, 10 10, 0 50, -10 10)");
double const distance = 5;
GeomPtr g0(wktreader.read(wkt0));
ensure(0 != g0.get());
ensure_equals(g0->getNumPoints(), std::size_t(5));
BufferParameters params;
params.setEndCapStyle(BufferParameters::CAP_FLAT);
params.setQuadrantSegments(8);
params.setJoinStyle(BufferParameters::JOIN_MITRE);
params.setMitreLimit(5.57F);
//params.setSingleSided(true); // DO NOT switch for non-areal input, see ticket #633
BufferBuilder builder(params);
ensure(distance > 0);
// left-side
{
GeomPtr gB(builder.bufferLineSingleSided(g0.get(), distance, true));
ensure(0 != gB.get());
ensure_equals(gB->getGeometryTypeId(), geos::geom::GEOS_LINESTRING);
// Left-side offset curve expected with 5+ vertices
ensure(gB->getNumPoints() >= g0->getNumPoints());
// For left-side offset curve, the offset will be at the left side of the input line
// and retain the same direction.
ensure_equals(
CGAlgorithms::isCCW(dynamic_cast<LineString*>(g0.get())->getCoordinatesRO()),
CGAlgorithms::isCCW(dynamic_cast<LineString*>(gB.get())->getCoordinatesRO()));
}
// right-side
{
GeomPtr gB(builder.bufferLineSingleSided(g0.get(), distance, false));
ensure(0 != gB.get());
ensure_equals(gB->getGeometryTypeId(), geos::geom::GEOS_LINESTRING);
// Right-side offset curve expected with 5+ vertices
ensure(gB->getNumPoints() >= g0->getNumPoints());
// For right-side offset curve, it'll be at the right side
// and in the opposite direction.
ensure_equals(
CGAlgorithms::isCCW(dynamic_cast<LineString*>(g0.get())->getCoordinatesRO()),
!CGAlgorithms::isCCW(dynamic_cast<LineString*>(gB.get())->getCoordinatesRO()));
}
}
/*public*/
Geometry*
BufferBuilder::bufferLineSingleSided( const Geometry* g, double distance,
bool leftSide )
{
// Returns the line used to create a single-sided buffer.
// Input requirement: Must be a LineString.
const LineString* l = dynamic_cast< const LineString* >( g );
if ( !l ) throw util::IllegalArgumentException("BufferBuilder::bufferLineSingleSided only accept linestrings");
// Get geometry factory and precision model.
const PrecisionModel* precisionModel = workingPrecisionModel;
if ( !precisionModel ) precisionModel = l->getPrecisionModel();
assert( precisionModel );
assert( l );
geomFact = l->getFactory();
// First, generate the two-sided buffer using a butt-cap.
BufferParameters modParams = bufParams;
modParams.setEndCapStyle(BufferParameters::CAP_FLAT);
Geometry* buf = 0;
// This is a (temp?) hack to workaround the fact that
// BufferBuilder BufferParamaters are immutable after
// construction, while we want to force the end cap
// style to FLAT for single-sided buffering
{
BufferBuilder tmp(modParams);
buf = tmp.buffer( l, distance );
}
// Create MultiLineStrings from this polygon.
Geometry* bufLineString = buf->getBoundary();
#ifdef GEOS_DEBUG_SSB
std::cerr << "input|" << *l << std::endl;
std::cerr << "buffer|" << *bufLineString << std::endl;
#endif
// Then, get the raw (i.e. unnoded) single sided offset curve.
OffsetCurveBuilder curveBuilder( precisionModel, modParams );
std::vector< CoordinateSequence* > lineList;
std::auto_ptr< CoordinateSequence > coords ( g->getCoordinates() );
curveBuilder.getSingleSidedLineCurve( coords.get(), distance,
lineList, leftSide, !leftSide );
coords.reset();
// Create a SegmentString from these coordinates.
SegmentString::NonConstVect curveList;
for ( unsigned int i = 0; i < lineList.size(); ++i )
{
CoordinateSequence* seq = lineList[i];
SegmentString* ss = new NodedSegmentString(seq, NULL);
curveList.push_back( ss );
}
// Node these SegmentStrings.
Noder* noder = getNoder( precisionModel );
noder->computeNodes( &curveList );
SegmentString::NonConstVect* nodedEdges = noder->getNodedSubstrings();
// Create a geometry out of the noded substrings.
std::vector< Geometry* >* singleSidedNodedEdges =
new std::vector< Geometry * >();
for ( unsigned int i = 0, n = nodedEdges->size(); i < n; ++i )
{
SegmentString* ss = ( *nodedEdges )[i];
Geometry* tmp = geomFact->createLineString(
ss->getCoordinates()->clone()
);
singleSidedNodedEdges->push_back( tmp );
}
if ( nodedEdges != &curveList ) delete nodedEdges;
for (size_t i=0, n=curveList.size(); i<n; ++i) delete curveList[i];
curveList.clear();
for (size_t i=0, n=lineList.size(); i<n; ++i) delete lineList[i];
lineList.clear();
Geometry* singleSided = geomFact->createMultiLineString(
singleSidedNodedEdges );
#ifdef GEOS_DEBUG_SSB
std::cerr << "edges|" << *singleSided << std::endl;
#endif
// Use the boolean operation intersect to obtain the line segments lying
// on both the butt-cap buffer and this multi-line.
//Geometry* intersectedLines = singleSided->intersection( bufLineString );
// NOTE: we use Snapped overlay because the actual buffer boundary might
// diverge from original offset curves due to the addition of
// intersections with caps and joins curves
using geos::operation::overlay::snap::SnapOverlayOp;
Geometry* intersectedLines = SnapOverlayOp::overlayOp(*singleSided, *bufLineString, OverlayOp::opINTERSECTION).release();
#ifdef GEOS_DEBUG_SSB
std::cerr << "intersection" << "|" << *intersectedLines << std::endl;
#endif
// Merge result lines together.
LineMerger lineMerge;
lineMerge.add( intersectedLines );
std::auto_ptr< std::vector< LineString* > > mergedLines (
lineMerge.getMergedLineStrings() );
// Convert the result into a std::vector< Geometry* >.
std::vector< Geometry* >* mergedLinesGeom = new std::vector< Geometry* >();
const Coordinate& startPoint = l->getCoordinatesRO()->front();
const Coordinate& endPoint = l->getCoordinatesRO()->back();
while( !mergedLines->empty() )
{
// Remove end points if they are a part of the original line to be
// buffered.
CoordinateSequence::AutoPtr coords(mergedLines->back()->getCoordinates());
if ( NULL != coords.get() )
{
// Use 98% of the buffer width as the point-distance requirement - this
// is to ensure that the point that is "distance" +/- epsilon is not
// included.
const double ptDistAllowance = 0.98 * distance;
// Use 102% of the buffer width as the line-length requirement - this
// is to ensure that line segments that is length "distance" +/-
// epsilon is removed.
const double segLengthAllowance = 1.02 * distance;
// Clean up the front of the list.
// Loop until the line's end is not inside the buffer width from
// the startPoint.
while ( coords->size() > 1 &&
coords->front().distance( startPoint ) < ptDistAllowance )
{
// Record the end segment length.
double segLength = coords->front().distance( ( *coords )[1] );
// Stop looping if there are no more points, or if the segment
// length is larger than the buffer width.
if ( coords->size() <= 1 || segLength > segLengthAllowance )
{
break;
}
// If the first point is less than buffer width away from the
// reference point, then delete the point.
coords->deleteAt( 0 );
}
while ( coords->size() > 1 &&
coords->front().distance( endPoint ) < ptDistAllowance )
{
double segLength = coords->front().distance( ( *coords )[1] );
if ( coords->size() <= 1 || segLength > segLengthAllowance )
{
break;
}
coords->deleteAt( 0 );
}
// Clean up the back of the list.
while ( coords->size() > 1 &&
coords->back().distance( startPoint ) < ptDistAllowance )
{
double segLength = coords->back().distance(
( *coords )[coords->size()-2] );
if ( coords->size() <= 1 || segLength > segLengthAllowance )
{
break;
}
coords->deleteAt( coords->size()-1 );
}
while ( coords->size() > 1 &&
coords->back().distance( endPoint ) < ptDistAllowance )
{
double segLength = coords->back().distance(
( *coords )[coords->size()-2] );
if ( coords->size() <= 1 || segLength > segLengthAllowance )
{
break;
}
coords->deleteAt( coords->size()-1 );
}
// Add the coordinates to the resultant line string.
if ( coords->size() > 1 )
{
mergedLinesGeom->push_back( geomFact->createLineString( coords.release() ) );
}
}
geomFact->destroyGeometry( mergedLines->back() );
mergedLines->pop_back();
}
// Clean up.
if ( noder != workingNoder ) delete noder;
geomFact->destroyGeometry( buf );
geomFact->destroyGeometry( bufLineString );
geomFact->destroyGeometry( singleSided );
geomFact->destroyGeometry( intersectedLines );
if ( mergedLinesGeom->size() > 1 ) return geomFact->createMultiLineString( mergedLinesGeom );
else
{
// Must be a single line
Geometry* single = (*mergedLinesGeom)[0];
delete mergedLinesGeom;
return single;
}
}
