//! Simplify the WKB-geometry using the specified tolerance
bool QgsMapToPixelSimplifier::simplifyWkbGeometry(
int simplifyFlags, QGis::WkbType wkbType,
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
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 = generalizeWkbGeometry( 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;
}
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.
// Check whether the LinearRing is really closed.
if ( isaLinearRing )
{
double x1, y1, x2, y2;
unsigned char* startWkbX = sourceWkb;
unsigned char* startWkbY = startWkbX + sizeOfDoubleX;
unsigned char* finalWkbX = sourceWkb + ( numPoints - 1 ) * ( sizeOfDoubleX + sizeOfDoubleY );
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;
if ( i == 0 ||
!isGeneralizable ||
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++;
}
r.combineExtentWith( x, y );
}
targetWkb = wkb2 + 4;
// Fix the topology of the geometry
if ( numTargetPoints <= ( isaLinearRing ? 2 : 1 ) )
{
unsigned char* targetTempWkb = targetWkb;
int targetWkbTempSize = targetWkbSize;
sourceWkb = sourcePrevWkb;
targetWkb = targetPrevWkb;
targetWkbSize = targetWkbPrevSize;
if ( generalizeWkbGeometry( wkbType, sourceWkb, sourceWkbSize, targetWkb, targetWkbSize, r, writeHeader ) )
return true;
targetWkb = targetTempWkb;
targetWkbSize = targetWkbTempSize;
}
if ( isaLinearRing )
{
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;
}
//! Simplify the WKB-geometry using the specified tolerance
bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbType wkbType, unsigned char* sourceWkb, size_t sourceWkbSize, unsigned char* targetWkb, size_t& targetWkbSize, const QgsRectangle& envelope, double map2pixelTol, bool writeHeader, bool isaLinearRing )
{
bool canbeGeneralizable = true;
bool hasZValue = QGis::wkbDimensions( wkbType ) == 3;
bool result = false;
// Can replace the geometry by its BBOX ?
if (( simplifyFlags & QgsMapToPixelSimplifier::SimplifyEnvelope ) && ( envelope.xMaximum() - envelope.xMinimum() ) < map2pixelTol && ( envelope.yMaximum() - envelope.yMinimum() ) < map2pixelTol )
{
canbeGeneralizable = generalizeWkbGeometry( wkbType, sourceWkb, sourceWkbSize, targetWkb, targetWkbSize, envelope, writeHeader );
if ( canbeGeneralizable ) return true;
}
if ( !( simplifyFlags & QgsMapToPixelSimplifier::SimplifyGeometry ) ) canbeGeneralizable = false;
// Write the main header of the geometry
if ( writeHeader )
{
memcpy( targetWkb, sourceWkb, 1 ); // 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;
}
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;
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 ) ) canbeGeneralizable = false;
int numTargetPoints = 0;
memcpy( targetWkb, &numTargetPoints, 4 );
targetWkb += 4;
targetWkbSize += 4;
double* ptr = ( double* )targetWkb;
map2pixelTol *= map2pixelTol; //-> Use mappixelTol for 'LengthSquare' calculations.
// Process each vertex...
for ( int i = 0, numPoints_i = ( isaLinearRing ? numPoints - 1 : numPoints ); i < numPoints_i; ++i )
{
memcpy( &x, sourceWkb, sizeof( double ) ); sourceWkb += sizeOfDoubleX;
memcpy( &y, sourceWkb, sizeof( double ) ); sourceWkb += sizeOfDoubleY;
if ( i == 0 || !canbeGeneralizable || QgsMapToPixelSimplifier::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++;
}
}
targetWkb = wkb2 + 4;
// Fix the topology of the geometry
if ( isaLinearRing )
{
memcpy( &x, targetWkb + 0, sizeof( double ) );
memcpy( &y, targetWkb + 8, sizeof( double ) );
memcpy( ptr, &x, sizeof( double ) ); ptr++;
memcpy( ptr, &y, sizeof( double ) ); ptr++;
numTargetPoints++;
}
targetWkbSize += numTargetPoints * 16;
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;
}
