//! 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() );
}
//! Simplify the WKB-geometry using the specified tolerance
bool QgsMapToPixelSimplifier::simplifyWkbGeometry(
int simplifyFlags,
SimplifyAlgorithm simplifyAlgorithm,
QGis::WkbType wkbType,
QgsConstWkbPtr sourceWkbPtr,
QgsWkbPtr targetWkbPtr,
int &targetWkbSize,
const QgsRectangle &envelope, double map2pixelTol,
bool writeHeader, bool isaLinearRing )
{
bool isGeneralizable = true;
bool result = false;
// Save initial WKB settings to use when the simplification creates invalid geometries
QgsConstWkbPtr sourcePrevWkbPtr( sourceWkbPtr );
QgsWkbPtr targetPrevWkbPtr( targetWkbPtr );
int targetWkbPrevSize = targetWkbSize;
// Can replace the geometry by its BBOX ?
if (( simplifyFlags & QgsMapToPixelSimplifier::SimplifyEnvelope ) &&
isGeneralizableByMapBoundingBox( envelope, map2pixelTol ) )
{
isGeneralizable = generalizeWkbGeometryByBoundingBox( wkbType, sourceWkbPtr, targetWkbPtr, targetWkbSize, envelope, writeHeader );
if ( isGeneralizable )
return true;
}
if ( !( simplifyFlags & QgsMapToPixelSimplifier::SimplifyGeometry ) )
isGeneralizable = false;
// Write the main header of the geometry
if ( writeHeader )
{
QgsWKBTypes::Type geometryType = sourceWkbPtr.readHeader();
targetWkbPtr << ( char ) QgsApplication::endian() << QgsWKBTypes::flatType( geometryType );
targetWkbSize += targetWkbPtr - targetPrevWkbPtr;
}
unsigned int flatType = QGis::flatType( wkbType );
// Write the geometry
if ( flatType == QGis::WKBLineString || isaLinearRing )
{
QgsWkbPtr savedTargetWkbPtr( targetWkbPtr );
double x = 0.0, y = 0.0, lastX = 0, lastY = 0;
QgsRectangle r;
r.setMinimal();
int skipZM = ( QGis::wkbDimensions( wkbType ) - 2 ) * sizeof( double );
Q_ASSERT( skipZM >= 0 );
int numPoints;
sourceWkbPtr >> numPoints;
if ( numPoints <= ( isaLinearRing ? 5 : 2 ) )
isGeneralizable = false;
QgsWkbPtr numPtr( targetWkbPtr );
int numTargetPoints = 0;
targetWkbPtr << numTargetPoints;
targetWkbSize += 4;
bool isLongSegment;
bool hasLongSegments = false; //-> To avoid replace the simplified geometry by its BBOX when there are 'long' segments.
bool badLuck = false;
// Check whether the LinearRing is really closed.
if ( isaLinearRing )
{
QgsConstWkbPtr checkPtr( sourceWkbPtr );
double x1, y1, x2, y2;
checkPtr >> x1 >> y1;
checkPtr += skipZM + ( numPoints - 2 ) * ( 2 * sizeof( double ) + skipZM );
checkPtr >> x2 >> y2;
isaLinearRing = qgsDoubleNear( x1, x2 ) && qgsDoubleNear( y1, y2 );
}
// Process each vertex...
if ( simplifyAlgorithm == 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 )
{
sourceWkbPtr >> x >> y;
sourceWkbPtr += skipZM;
if ( i == 0 ||
!isGeneralizable ||
!equalSnapToGrid( x, y, lastX, lastY, gridOriginX, gridOriginY, gridInverseSizeXY ) ||
( !isaLinearRing && ( i == 1 || i >= numPoints - 2 ) ) )
{
targetWkbPtr << x << y;
lastX = x;
lastY = y;
numTargetPoints++;
}
r.combineExtentWith( x, y );
}
}
//! Simplify the WKB-geometry using the specified tolerance
bool QgsMapToPixelSimplifier::simplifyWkbGeometry(
int simplifyFlags, QGis::WkbType wkbType,
const unsigned char* sourceWkb, size_t sourceWkbSize,
unsigned char* targetWkb, size_t& targetWkbSize,
const QgsRectangle& envelope, double map2pixelTol,
bool writeHeader, bool isaLinearRing )
{
bool isGeneralizable = true;
bool hasZValue = QGis::wkbDimensions( wkbType ) == 3;
bool result = false;
// Save initial WKB settings to use when the simplification creates invalid geometries
const unsigned char* sourcePrevWkb = sourceWkb;
unsigned char* targetPrevWkb = targetWkb;
size_t targetWkbPrevSize = targetWkbSize;
// Can replace the geometry by its BBOX ?
if (( simplifyFlags & QgsMapToPixelSimplifier::SimplifyEnvelope ) &&
isGeneralizableByMapBoundingBox( envelope, map2pixelTol ) )
{
isGeneralizable = generalizeWkbGeometryByBoundingBox( wkbType, sourceWkb, sourceWkbSize, targetWkb, targetWkbSize, envelope, writeHeader );
if ( isGeneralizable )
return true;
}
if ( !( simplifyFlags & QgsMapToPixelSimplifier::SimplifyGeometry ) )
isGeneralizable = false;
// Write the main header of the geometry
if ( writeHeader )
{
targetWkb[0] = sourceWkb[0]; // byteOrder
sourceWkb += 1;
targetWkb += 1;
int geometryType;
memcpy( &geometryType, sourceWkb, 4 );
int flatType = QGis::flatType(( QGis::WkbType )geometryType );
memcpy( targetWkb, &flatType, 4 ); // type
sourceWkb += 4;
targetWkb += 4;
targetWkbSize += 5;
}
const unsigned char* wkb1 = sourceWkb;
unsigned char* wkb2 = targetWkb;
unsigned int flatType = QGis::flatType( wkbType );
// Write the geometry
if ( flatType == QGis::WKBLineString || isaLinearRing )
{
double x, y, lastX = 0, lastY = 0;
QgsRectangle r;
r.setMinimal();
int sizeOfDoubleX = sizeof( double );
int sizeOfDoubleY = QGis::wkbDimensions( wkbType ) == 3 /*hasZValue*/ ? 2 * sizeof( double ) : sizeof( double );
int numPoints;
memcpy( &numPoints, sourceWkb, 4 );
sourceWkb += 4;
if ( numPoints <= ( isaLinearRing ? 5 : 2 ) )
isGeneralizable = false;
int numTargetPoints = 0;
memcpy( targetWkb, &numTargetPoints, 4 );
targetWkb += 4;
targetWkbSize += 4;
double* ptr = ( double* )targetWkb;
map2pixelTol *= map2pixelTol; //-> Use mappixelTol for 'LengthSquare' calculations.
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 )
{
double x1, y1, x2, y2;
const unsigned char* startWkbX = sourceWkb;
const unsigned char* startWkbY = startWkbX + sizeOfDoubleX;
const unsigned char* finalWkbX = sourceWkb + ( numPoints - 1 ) * ( sizeOfDoubleX + sizeOfDoubleY );
const unsigned char* finalWkbY = finalWkbX + sizeOfDoubleX;
memcpy( &x1, startWkbX, sizeof( double ) );
memcpy( &y1, startWkbY, sizeof( double ) );
memcpy( &x2, finalWkbX, sizeof( double ) );
memcpy( &y2, finalWkbY, sizeof( double ) );
isaLinearRing = ( x1 == x2 ) && ( y1 == y2 );
}
// Process each vertex...
for ( int i = 0; i < numPoints; ++i )
{
memcpy( &x, sourceWkb, sizeof( double ) ); sourceWkb += sizeOfDoubleX;
memcpy( &y, sourceWkb, sizeof( double ) ); sourceWkb += sizeOfDoubleY;
isLongSegment = false;
if ( i == 0 ||
!isGeneralizable ||
( isLongSegment = ( calculateLengthSquared2D( x, y, lastX, lastY ) > map2pixelTol ) ) ||
( !isaLinearRing && ( i == 1 || i >= numPoints - 2 ) ) )
{
memcpy( ptr, &x, sizeof( double ) ); lastX = x; ptr++;
memcpy( ptr, &y, sizeof( double ) ); lastY = y; ptr++;
numTargetPoints++;
hasLongSegments |= isLongSegment;
}
r.combineExtentWith( x, y );
}
targetWkb = wkb2 + 4;
if ( numTargetPoints < ( 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)
unsigned char* targetTempWkb = targetWkb;
size_t targetWkbTempSize = targetWkbSize;
sourceWkb = sourcePrevWkb;
targetWkb = targetPrevWkb;
targetWkbSize = targetWkbPrevSize;
if ( generalizeWkbGeometryByBoundingBox( wkbType, sourceWkb, sourceWkbSize, targetWkb, targetWkbSize, r, writeHeader ) )
return true;
targetWkb = targetTempWkb;
targetWkbSize = targetWkbTempSize;
}
else
{
// Bad luck! The simplified geometry is invalid and approximation by bounding box
// would create artifacts due to long segments. Worst of all, we may have overwritten
// the original coordinates by the simplified ones (source and target WKB ptr can be the same)
// so we cannot even undo the changes here. We will return invalid geometry and hope that
// other pieces of QGIS will survive that :-/
}
}
if ( isaLinearRing )
{
// make sure we keep the linear ring closed
memcpy( &x, targetWkb + 0, sizeof( double ) );
memcpy( &y, targetWkb + sizeof( double ), sizeof( double ) );
if ( lastX != x || lastY != y )
{
memcpy( ptr, &x, sizeof( double ) ); ptr++;
memcpy( ptr, &y, sizeof( double ) ); ptr++;
numTargetPoints++;
}
}
targetWkbSize += numTargetPoints * sizeof( double ) * 2;
targetWkb = wkb2;
memcpy( targetWkb, &numTargetPoints, 4 );
result = numPoints != numTargetPoints;
}
else if ( flatType == QGis::WKBPolygon )
{
int numRings;
memcpy( &numRings, sourceWkb, 4 );
sourceWkb += 4;
memcpy( targetWkb, &numRings, 4 );
targetWkb += 4;
targetWkbSize += 4;
for ( int i = 0; i < numRings; ++i )
{
int numPoints_i;
memcpy( &numPoints_i, sourceWkb, 4 );
QgsRectangle envelope_i = numRings == 1 ? envelope : calculateBoundingBox( wkbType, sourceWkb + 4, numPoints_i );
size_t sourceWkbSize_i = 4 + numPoints_i * ( hasZValue ? 3 : 2 ) * sizeof( double );
size_t targetWkbSize_i = 0;
result |= simplifyWkbGeometry( simplifyFlags, wkbType, sourceWkb, sourceWkbSize_i, targetWkb, targetWkbSize_i, envelope_i, map2pixelTol, false, true );
sourceWkb += sourceWkbSize_i;
targetWkb += targetWkbSize_i;
targetWkbSize += targetWkbSize_i;
}
}
else if ( flatType == QGis::WKBMultiLineString || flatType == QGis::WKBMultiPolygon )
{
int numGeoms;
memcpy( &numGeoms, sourceWkb, 4 );
sourceWkb += 4;
wkb1 += 4;
memcpy( targetWkb, &numGeoms, 4 );
targetWkb += 4;
targetWkbSize += 4;
for ( int i = 0; i < numGeoms; ++i )
{
size_t sourceWkbSize_i = 0;
size_t targetWkbSize_i = 0;
// ... calculate the wkb-size of the current child complex geometry
if ( flatType == QGis::WKBMultiLineString )
{
int numPoints_i;
memcpy( &numPoints_i, wkb1 + 5, 4 );
int wkbSize_i = 4 + numPoints_i * ( hasZValue ? 3 : 2 ) * sizeof( double );
sourceWkbSize_i += 5 + wkbSize_i;
wkb1 += 5 + wkbSize_i;
}
else
{
int numPrings_i;
memcpy( &numPrings_i, wkb1 + 5, 4 );
sourceWkbSize_i = 9;
wkb1 += 9;
for ( int j = 0; j < numPrings_i; ++j )
{
int numPoints_i;
memcpy( &numPoints_i, wkb1, 4 );
int wkbSize_i = 4 + numPoints_i * ( hasZValue ? 3 : 2 ) * sizeof( double );
sourceWkbSize_i += wkbSize_i;
wkb1 += wkbSize_i;
}
}
result |= simplifyWkbGeometry( simplifyFlags, QGis::singleType( wkbType ), sourceWkb, sourceWkbSize_i, targetWkb, targetWkbSize_i, envelope, map2pixelTol, true, false );
sourceWkb += sourceWkbSize_i;
targetWkb += targetWkbSize_i;
targetWkbSize += targetWkbSize_i;
}
}
return result;
}