//! Returns a simplified version the specified geometry (Removing duplicated points) when is applied the specified map2pixel context
QgsGeometry* QgsMapToPixelSimplifier::simplify( QgsGeometry* geometry ) const
{
QgsGeometry* g = new QgsGeometry();
size_t wkbSize = geometry->wkbSize();
unsigned char* wkb = ( unsigned char* )malloc( wkbSize );
memcpy( wkb, geometry->asWkb(), wkbSize );
g->fromWkb( wkb, wkbSize );
simplifyGeometry( g, mSimplifyFlags, mTolerance );
return g;
}
//! Returns a simplified version the specified geometry (Removing duplicated points) when is applied the specified map2pixel context
QgsGeometry QgsMapToPixelSimplifier::simplify( const QgsGeometry& geometry ) const
{
if ( geometry.isEmpty() )
{
return QgsGeometry();
}
if ( mSimplifyFlags == QgsMapToPixelSimplifier::NoFlags )
{
return geometry;
}
// Check whether the geometry can be simplified using the map2pixel context
const QgsWkbTypes::Type singleType = QgsWkbTypes::singleType( geometry.wkbType() );
const QgsWkbTypes::Type flatType = QgsWkbTypes::flatType( singleType );
if ( flatType == QgsWkbTypes::Point )
{
return geometry;
}
const bool isaLinearRing = flatType == QgsWkbTypes::Polygon;
const int numPoints = geometry.geometry()->nCoordinates();
if ( numPoints <= ( isaLinearRing ? 6 : 3 ) )
{
// No simplify simple geometries
return geometry;
}
const QgsRectangle envelope = geometry.boundingBox();
if ( qMax( envelope.width(), envelope.height() ) / numPoints > mTolerance * 2.0 )
{
//points are in average too far apart to lead to any significant simplification
return geometry;
}
return simplifyGeometry( mSimplifyFlags, mSimplifyAlgorithm, geometry.wkbType(), *geometry.geometry(), envelope, mTolerance, false );
}
//! Simplify the WKB-geometry using the specified tolerance
QgsGeometry QgsMapToPixelSimplifier::simplifyGeometry(
int simplifyFlags,
SimplifyAlgorithm simplifyAlgorithm,
QgsWkbTypes::Type wkbType,
const QgsAbstractGeometry& geometry,
const QgsRectangle &envelope, double map2pixelTol,
bool isaLinearRing )
{
bool isGeneralizable = true;
// Can replace the geometry by its BBOX ?
if (( simplifyFlags & QgsMapToPixelSimplifier::SimplifyEnvelope ) &&
isGeneralizableByMapBoundingBox( envelope, map2pixelTol ) )
{
return generalizeWkbGeometryByBoundingBox( wkbType, geometry, envelope );
}
if ( !( simplifyFlags & QgsMapToPixelSimplifier::SimplifyGeometry ) )
isGeneralizable = false;
const QgsWkbTypes::Type flatType = QgsWkbTypes::flatType( wkbType );
// Write the geometry
if ( flatType == QgsWkbTypes::LineString || flatType == QgsWkbTypes::CircularString )
{
const QgsCurve& srcCurve = dynamic_cast<const QgsCurve&>( geometry );
QScopedPointer<QgsCurve> output( createEmptySameTypeGeom( srcCurve ) );
double x = 0.0, y = 0.0, lastX = 0.0, lastY = 0.0;
QgsRectangle r;
r.setMinimal();
const int numPoints = srcCurve.numPoints();
if ( numPoints <= ( isaLinearRing ? 4 : 2 ) )
isGeneralizable = false;
bool isLongSegment;
bool hasLongSegments = false; //-> To avoid replace the simplified geometry by its BBOX when there are 'long' segments.
// Check whether the LinearRing is really closed.
if ( isaLinearRing )
{
isaLinearRing = qgsDoubleNear( srcCurve.xAt( 0 ), srcCurve.xAt( numPoints - 1 ) ) &&
qgsDoubleNear( srcCurve.yAt( 0 ), srcCurve.yAt( numPoints - 1 ) );
}
// Process each vertex...
switch ( simplifyAlgorithm )
{
case SnapToGrid:
{
double gridOriginX = envelope.xMinimum();
double gridOriginY = envelope.yMinimum();
// Use a factor for the maximum displacement distance for simplification, similar as GeoServer does
float gridInverseSizeXY = map2pixelTol != 0 ? ( float )( 1.0f / ( 0.8 * map2pixelTol ) ) : 0.0f;
for ( int i = 0; i < numPoints; ++i )
{
x = srcCurve.xAt( i );
y = srcCurve.yAt( i );
if ( i == 0 ||
!isGeneralizable ||
!equalSnapToGrid( x, y, lastX, lastY, gridOriginX, gridOriginY, gridInverseSizeXY ) ||
( !isaLinearRing && ( i == 1 || i >= numPoints - 2 ) ) )
{
output->insertVertex( QgsVertexId( 0, 0, output->numPoints() ), QgsPointV2( x, y ) );
lastX = x;
lastY = y;
}
r.combineExtentWith( x, y );
}
break;
}
case Visvalingam:
{
map2pixelTol *= map2pixelTol; //-> Use mappixelTol for 'Area' calculations.
EFFECTIVE_AREAS ea( srcCurve );
int set_area = 0;
ptarray_calc_areas( &ea, isaLinearRing ? 4 : 2, set_area, map2pixelTol );
for ( int i = 0; i < numPoints; ++i )
{
if ( ea.res_arealist[ i ] > map2pixelTol )
{
output->insertVertex( QgsVertexId( 0, 0, output->numPoints() ), ea.inpts.at( i ) );
}
}
break;
}
case Distance:
{
map2pixelTol *= map2pixelTol; //-> Use mappixelTol for 'LengthSquare' calculations.
for ( int i = 0; i < numPoints; ++i )
{
x = srcCurve.xAt( i );
y = srcCurve.yAt( i );
isLongSegment = false;
if ( i == 0 ||
!isGeneralizable ||
( isLongSegment = ( calculateLengthSquared2D( x, y, lastX, lastY ) > map2pixelTol ) ) ||
( !isaLinearRing && ( i == 1 || i >= numPoints - 2 ) ) )
{
output->insertVertex( QgsVertexId( 0, 0, output->numPoints() ), QgsPointV2( x, y ) );
lastX = x;
lastY = y;
hasLongSegments |= isLongSegment;
}
r.combineExtentWith( x, y );
}
}
}
if ( output->numPoints() < ( isaLinearRing ? 4 : 2 ) )
{
// we simplified the geometry too much!
if ( !hasLongSegments )
{
// approximate the geometry's shape by its bounding box
// (rect for linear ring / one segment for line string)
return generalizeWkbGeometryByBoundingBox( wkbType, geometry, r );
}
else
{
// Bad luck! The simplified geometry is invalid and approximation by bounding box
// would create artifacts due to long segments.
// We will return the original geometry
return QgsGeometry( geometry.clone() );
}
}
if ( isaLinearRing )
{
// make sure we keep the linear ring closed
if ( !qgsDoubleNear( lastX, output->xAt( 0 ) ) || !qgsDoubleNear( lastY, output->yAt( 0 ) ) )
{
output->insertVertex( QgsVertexId( 0, 0, output->numPoints() ), QgsPointV2( output->xAt( 0 ), output->yAt( 0 ) ) );
}
}
return QgsGeometry( output.take() );
}
else if ( flatType == QgsWkbTypes::Polygon )
{
const QgsPolygonV2& srcPolygon = dynamic_cast<const QgsPolygonV2&>( geometry );
QScopedPointer<QgsPolygonV2> polygon( new QgsPolygonV2() );
polygon->setExteriorRing( dynamic_cast<QgsCurve*>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, srcPolygon.exteriorRing()->wkbType(), *srcPolygon.exteriorRing(), envelope, map2pixelTol, true ).geometry()->clone() ) );
for ( int i = 0; i < srcPolygon.numInteriorRings(); ++i )
{
const QgsCurve* sub = srcPolygon.interiorRing( i );
polygon->addInteriorRing( dynamic_cast<QgsCurve*>( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, true ).geometry()->clone() ) );
}
return QgsGeometry( polygon.take() );
}
else if ( QgsWkbTypes::isMultiType( flatType ) )
{
const QgsGeometryCollection& srcCollection = dynamic_cast<const QgsGeometryCollection&>( geometry );
QScopedPointer<QgsGeometryCollection> collection( createEmptySameTypeGeom( srcCollection ) );
const int numGeoms = srcCollection.numGeometries();
for ( int i = 0; i < numGeoms; ++i )
{
const QgsAbstractGeometry* sub = srcCollection.geometryN( i );
collection->addGeometry( simplifyGeometry( simplifyFlags, simplifyAlgorithm, sub->wkbType(), *sub, envelope, map2pixelTol, false ).geometry()->clone() );
}
return QgsGeometry( collection.take() );
}
return QgsGeometry( geometry.clone() );
}
//! Simplifies the geometry (Removing duplicated points) when is applied the specified map2pixel context
bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry ) const
{
return simplifyGeometry( geometry, mSimplifyFlags, mTolerance );
}