QgsConstWkbPtr QgsClipper::clippedLineWKB( QgsConstWkbPtr wkbPtr, const QgsRectangle& clipExtent, QPolygonF& line )
{
QgsWKBTypes::Type wkbType = wkbPtr.readHeader();
int nPoints;
wkbPtr >> nPoints;
int skipZM = ( QgsWKBTypes::coordDimensions( wkbType ) - 2 ) * sizeof( double );
if ( static_cast<int>( nPoints * ( 2 * sizeof( double ) + skipZM ) ) > wkbPtr.remaining() )
{
QgsDebugMsg( QString( "%1 points exceed wkb length (%2>%3)" ).arg( nPoints ).arg( nPoints * ( 2 * sizeof( double ) + skipZM ) ).arg( wkbPtr.remaining() ) );
return QgsConstWkbPtr( nullptr, 0 );
}
double p0x, p0y, p1x = 0.0, p1y = 0.0; //original coordinates
double p1x_c, p1y_c; //clipped end coordinates
double lastClipX = 0.0, lastClipY = 0.0; //last successfully clipped coords
line.clear();
line.reserve( nPoints + 1 );
for ( int i = 0; i < nPoints; ++i )
{
if ( i == 0 )
{
wkbPtr >> p1x >> p1y;
wkbPtr += skipZM;
continue;
}
else
{
//! Generalize the WKB-geometry using the BBOX of the original geometry
static bool generalizeWkbGeometryByBoundingBox(
QGis::WkbType wkbType,
QgsConstWkbPtr sourceWkbPtr,
QgsWkbPtr targetWkbPtr,
int &targetWkbSize,
const QgsRectangle &envelope, bool writeHeader )
{
QgsWkbPtr savedTargetWkb( targetWkbPtr );
unsigned int geometryType = QGis::singleType( QGis::flatType( wkbType ) );
int skipZM = ( QGis::wkbDimensions( wkbType ) - 2 ) * sizeof( double );
Q_ASSERT( skipZM >= 0 );
// If the geometry is already minimal skip the generalization
int minimumSize = geometryType == QGis::WKBLineString ? 4 + 2 * ( 2 * sizeof( double ) + skipZM ) : 8 + 5 * ( 2 * sizeof( double ) + skipZM );
if ( writeHeader )
minimumSize += 5;
if ( sourceWkbPtr.remaining() <= minimumSize )
{
targetWkbSize = 0;
return false;
}
double x1 = envelope.xMinimum();
double y1 = envelope.yMinimum();
double x2 = envelope.xMaximum();
double y2 = envelope.yMaximum();
// Write the main header of the geometry
if ( writeHeader )
{
targetWkbPtr << ( char ) QgsApplication::endian() << geometryType;
if ( geometryType == QGis::WKBPolygon ) // numRings
{
targetWkbPtr << 1;
}
}
// Write the generalized geometry
if ( geometryType == QGis::WKBLineString )
{
targetWkbPtr << 2 << x1 << y1 << x2 << y2;
}
else
{
targetWkbPtr << 5 << x1 << y1 << x2 << y1 << x2 << y2 << x1 << y2 << x1 << y1;
}
targetWkbSize += targetWkbPtr - savedTargetWkb;
return true;
}
QgsConstWkbPtr QgsClipper::clippedLineWKB( QgsConstWkbPtr& wkbPtr, const QgsRectangle& clipExtent, QPolygonF& line )
{
QgsWKBTypes::Type wkbType = wkbPtr.readHeader();
int nPoints;
wkbPtr >> nPoints;
int skipZM = ( QgsWKBTypes::coordDimensions( wkbType ) - 2 ) * sizeof( double );
if ( static_cast<int>( nPoints * ( 2 * sizeof( double ) + skipZM ) ) > wkbPtr.remaining() )
{
QgsDebugMsg( QString( "%1 points exceed wkb length (%2>%3)" ).arg( nPoints ).arg( nPoints * ( 2 * sizeof( double ) + skipZM ) ).arg( wkbPtr.remaining() ) );
return QgsConstWkbPtr( nullptr, 0 );
}
double p0x, p0y, p1x = 0.0, p1y = 0.0; //original coordinates
double p1x_c, p1y_c; //clipped end coordinates
double lastClipX = 0.0, lastClipY = 0.0; //last successfully clipped coords
QPolygonF pts;
wkbPtr -= sizeof( unsigned int );
wkbPtr >> pts;
nPoints = pts.size();
line.clear();
line.reserve( nPoints + 1 );
QPointF *ptr = pts.data();
for ( int i = 0; i < nPoints; ++i, ++ptr )
{
if ( i == 0 )
{
p1x = ptr->rx();
p1y = ptr->ry();
continue;
}
else
{
p0x = p1x;
p0y = p1y;
p1x = ptr->rx();
p1y = ptr->ry();
p1x_c = p1x;
p1y_c = p1y;
if ( clipLineSegment( clipExtent.xMinimum(), clipExtent.xMaximum(), clipExtent.yMinimum(), clipExtent.yMaximum(),
p0x, p0y, p1x_c, p1y_c ) )
{
bool newLine = !line.isEmpty() && ( !qgsDoubleNear( p0x, lastClipX ) || !qgsDoubleNear( p0y, lastClipY ) );
if ( newLine )
{
//add edge points to connect old and new line
connectSeparatedLines( lastClipX, lastClipY, p0x, p0y, clipExtent, line );
}
if ( line.size() < 1 || newLine )
{
//add first point
line << QPointF( p0x, p0y );
}
//add second point
lastClipX = p1x_c;
lastClipY = p1y_c;
line << QPointF( p1x_c, p1y_c );
}
}
}
return wkbPtr;
}