bool QgsGeometryValidator::intersectLines( const QgsPoint& p, QgsVector v, const QgsPoint& q, QgsVector w, QgsPoint &s )
{
  double d = v.y() * w.x() - v.x() * w.y();

  if ( qgsDoubleNear( d, 0 ) )
    return false;

  double dx = q.x() - p.x();
  double dy = q.y() - p.y();
  double k = ( dy * w.x() - dx * w.y() ) / d;

  s = p + v * k;

  return true;
}
bool QgsGeometryUtils::lineIntersection( const QgsPointV2& p1, const QgsVector& v, const QgsPointV2& q1, const QgsVector& w, QgsPointV2& inter )
{
  double d = v.y() * w.x() - v.x() * w.y();

  if ( d == 0 )
    return false;

  double dx = q1.x() - p1.x();
  double dy = q1.y() - p1.y();
  double k = ( dy * w.x() - dx * w.y() ) / d;

  inter = QgsPointV2( p1.x() + v.x() * k, p1.y() + v.y() * k );

  return true;
}
void QgsSelectedFeature::moveSelectedVertexes( QgsVector v )
{
  int nUpdates = 0;
  Q_FOREACH ( QgsVertexEntry *entry, mVertexMap )
  {
    if ( entry->isSelected() )
      nUpdates++;
  }

  if ( nUpdates == 0 )
    return;

  mVlayer->beginEditCommand( QObject::tr( "Moved vertices" ) );
  int topologicalEditing = QgsProject::instance()->readNumEntry( "Digitizing", "/TopologicalEditing", 0 );

  beginGeometryChange();

  QMultiMap<double, QgsSnappingResult> currentResultList;
  for ( int i = mVertexMap.size() - 1; i > -1 && nUpdates > 0; i-- )
  {
    QgsVertexEntry *entry = mVertexMap.value( i, nullptr );
    if ( !entry || !entry->isSelected() )
      continue;

    if ( topologicalEditing )
    {
      // snap from current vertex
      currentResultList.clear();
      mVlayer->snapWithContext( entry->pointV1(), ZERO_TOLERANCE, currentResultList, QgsSnapper::SnapToVertex );
    }

    // only last update should trigger the geometry update
    // as vertex selection gets lost on the update
    if ( --nUpdates == 0 )
      endGeometryChange();

    QgsPointV2 p = entry->point();
    p.setX( p.x() + v.x() );
    p.setY( p.y() + v.y() );
    mVlayer->moveVertex( p, mFeatureId, i );

    if ( topologicalEditing )
    {
      QMultiMap<double, QgsSnappingResult>::iterator resultIt =  currentResultList.begin();

      for ( ; resultIt != currentResultList.end(); ++resultIt )
      {
        // move all other
        if ( mFeatureId !=  resultIt.value().snappedAtGeometry )
          mVlayer->moveVertex( p, resultIt.value().snappedAtGeometry, resultIt.value().snappedVertexNr );
      }
    }
  }

  if ( nUpdates > 0 )
    endGeometryChange();

  mVlayer->endEditCommand();
}
//
// distance of point q from line through p in direction v
// return >0  => q lies left of the line
//        <0  => q lies right of the line
//
double QgsGeometryValidator::distLine2Point( const QgsPoint& p, QgsVector v, const QgsPoint& q )
{
  if ( qgsDoubleNear( v.length(), 0 ) )
  {
    throw QgsException( QObject::tr( "invalid line" ) );
  }

  return ( v.x()*( q.y() - p.y() ) - v.y()*( q.x() - p.x() ) ) / v.length();
}
void QgsMapToolNodeTool::canvasMoveEvent( QMouseEvent * e )
{
  if ( !mSelectedFeature || !mClicked )
    return;

  QgsVectorLayer* vlayer = mSelectedFeature->vlayer();
  Q_ASSERT( vlayer );

  mSelectAnother = false;

  if ( mMoving )
  {
    // create rubberband, if none exists
    if ( mRubberBands.empty() )
    {
      if ( mIsPoint )
      {
        QList<QgsVertexEntry*> &vertexMap = mSelectedFeature->vertexMap();
        for ( int i = 0; i < vertexMap.size(); i++ )
        {
          if ( vertexMap[i]->isSelected() )
          {
            QgsRubberBand* rb = createRubberBandMarker( vertexMap[i]->point(), vlayer );
            mRubberBands.append( rb );
          }
        }
      }
      createMovingRubberBands();

      QList<QgsSnappingResult> snapResults;
      QgsPoint posMapCoord = snapPointFromResults( snapResults, e->pos() );
      mPosMapCoordBackup = posMapCoord;
    }
    else
    {
      // move rubberband
      QList<QgsSnappingResult> snapResults;
      mSnapper.snapToBackgroundLayers( e->pos(), snapResults, QList<QgsPoint>() << mClosestMapVertex );

      // get correct coordinates to move to
      QgsPoint posMapCoord = snapPointFromResults( snapResults, e->pos() );

      QgsPoint pressMapCoords;
      if ( snapResults.size() > 0 )
      {
        pressMapCoords = mClosestMapVertex;
      }
      else
      {
        pressMapCoords = toMapCoordinates( mPressCoordinates );
      }

      QgsVector offset = posMapCoord - pressMapCoords;

      // handle points
      if ( mIsPoint )
      {
        for ( int i = 0; i < mRubberBands.size(); i++ )
        {
          mRubberBands[i]->setTranslationOffset( offset.x(), offset.y() );
        }
        return;
      }

      // move points
      QList<QgsVertexEntry*> &vertexMap = mSelectedFeature->vertexMap();
      for ( int i = 0; i < vertexMap.size(); i++ )
      {
        if ( !vertexMap[i]->isSelected() )
          continue;

        QgsPoint p = toMapCoordinates( vlayer, vertexMap[i]->point() ) + offset;

        mRubberBands[vertexMap[i]->rubberBandNr()]->movePoint( vertexMap[i]->rubberBandIndex(), p );

        if ( vertexMap[i]->rubberBandIndex() == 0 )
        {
          mRubberBands[vertexMap[i]->rubberBandNr()]->movePoint( 0, p );
        }
      }

      // topological editing
      offset = posMapCoord - mPosMapCoordBackup;
      for ( int i = 0; i < mTopologyRubberBand.size(); i++ )
      {
        for ( int pointIndex = 0; pointIndex < mTopologyRubberBand[i]->numberOfVertices(); pointIndex++ )
        {
          if ( mTopologyRubberBandVertexes[i]->contains( pointIndex ) )
          {
            const QgsPoint* point = mTopologyRubberBand[i]->getPoint( 0, pointIndex );
            if ( point == 0 )
            {
              break;
            }
            mTopologyRubberBand[i]->movePoint( pointIndex, *point + offset );
          }
        }
      }

      mPosMapCoordBackup = posMapCoord;
    }
  }
  else
  {
    if ( !mSelectionRectangle )
    {
      mSelectionRectangle = true;
      mSelectionRubberBand = new QRubberBand( QRubberBand::Rectangle, mCanvas );
      mRect = new QRect();
      mRect->setTopLeft( mPressCoordinates );
    }
    mRect->setBottomRight( e->pos() );
    QRect normalizedRect = mRect->normalized();
    mSelectionRubberBand->setGeometry( normalizedRect );
    mSelectionRubberBand->show();
  }
}