C++ QgsVectorLayer::destroyEditCommand方法代码示例

void QgsMapToolOffsetCurve::canvasReleaseEvent( QMouseEvent * e )
{
  Q_UNUSED( e );
  QgsVectorLayer* vlayer = currentVectorLayer();
  if ( !vlayer )
  {
    deleteRubberBandAndGeometry();
    return;
  }

  if ( !mGeometryModified )
  {
    deleteRubberBandAndGeometry();
    vlayer->destroyEditCommand();
    return;
  }

  if ( mMultiPartGeometry )
  {
    mModifiedGeometry.convertToMultiType();
  }

  vlayer->beginEditCommand( tr( "Offset curve" ) );

  bool editOk;
  if ( mSourceLayerId == vlayer->id() && !mForceCopy )
  {
    editOk = vlayer->changeGeometry( mModifiedFeature, &mModifiedGeometry );
  }
  else
  {
    QgsFeature f;
    f.setGeometry( mModifiedGeometry );

    //add empty values for all fields (allows inserting attribute values via the feature form in the same session)
    QgsAttributes attrs( vlayer->pendingFields().count() );
    const QgsFields& fields = vlayer->pendingFields();
    for ( int idx = 0; idx < fields.count(); ++idx )
    {
      attrs[idx] = QVariant();
    }
    f.setAttributes( attrs );
    editOk = vlayer->addFeature( f );
  }

  if ( editOk )
  {
    vlayer->endEditCommand();
  }
  else
  {
    vlayer->destroyEditCommand();
  }

  deleteRubberBandAndGeometry();
  deleteDistanceItem();
  delete mSnapVertexMarker; mSnapVertexMarker = 0;
  mForceCopy = false;
  mCanvas->refresh();
}

void QgsMapToolShowHideLabels::showHideLabels( QMouseEvent * e )
{
  QgsMapLayer* layer = mCanvas->currentLayer();

  QgsVectorLayer* vlayer = dynamic_cast<QgsVectorLayer*>( layer );
  if ( !vlayer )
  {
    QgsDebugMsg( "Failed to cast label layer to vector layer" );
    return;
  }
  if ( !vlayer->isEditable() )
  {
    QgsDebugMsg( "Vector layer not editable, skipping label" );
    return;
  }

  bool doHide = e->modifiers() & Qt::ShiftModifier;
  bool labelChanged = false;
  QString editTxt = doHide ? tr( "Hid labels" ) : tr( "Showed labels" );
  vlayer->beginEditCommand( editTxt );

  if ( !doHide )
  {
    QgsDebugMsg( "Showing labels operation" );

    QgsFeatureIds selectedFeatIds;
    if ( !selectedFeatures( vlayer, selectedFeatIds ) )
    {
      vlayer->destroyEditCommand();
      return;
    }

    QgsDebugMsg( "Number of selected labels or features: " + QString::number( selectedFeatIds.size() ) );

    if ( selectedFeatIds.isEmpty() )
    {
      vlayer->destroyEditCommand();
      return;
    }

    Q_FOREACH ( QgsFeatureId fid, selectedFeatIds )
    {
      mCurrentLabel.pos.featureId = fid;

      mCurrentLabel.pos.isDiagram = false;
      bool labChanged = showHide( vlayer, true );

      mCurrentLabel.pos.isDiagram = true;
      bool diagChanged = showHide( vlayer, true );

      if ( labChanged || diagChanged )
      {
        // TODO: highlight features (maybe with QTimer?)
        labelChanged = labelChanged || true;
      }
    }

void QgsMapToolShowHideLabels::showHideLabels( QMouseEvent *e )
{
  QgsMapLayer *layer = mCanvas->currentLayer();
  QgsVectorLayer *vlayer = dynamic_cast<QgsVectorLayer *>( layer );
  if ( !vlayer )
    return;

  bool doHide = e->modifiers() & Qt::ShiftModifier;
  QString editTxt = doHide ? tr( "Hid labels" ) : tr( "Showed labels" );
  vlayer->beginEditCommand( editTxt );

  bool labelChanged = false;
  if ( doHide )
  {
    QList<QgsLabelPosition> positions;
    if ( selectedLabelFeatures( vlayer, positions ) )
    {
      for ( const QgsLabelPosition &pos : qgis::as_const( positions ) )
      {
        if ( showHide( pos, false ) )
          labelChanged = true;
      }
    }
  }
  else
  {
    QgsFeatureIds fids;
    if ( selectedFeatures( vlayer, fids ) )
    {
      for ( const QgsFeatureId &fid : qgis::as_const( fids ) )
      {
        QgsLabelPosition pos;
        pos.featureId = fid;
        pos.layerID = vlayer->id();

        // we want to show labels...
        pos.isDiagram = false;
        if ( showHide( pos, true ) )
          labelChanged = true;

        // ... and diagrams
        pos.isDiagram = true;
        if ( showHide( pos, true ) )
          labelChanged = true;
      }
    }
  }

  if ( labelChanged )
  {
    vlayer->endEditCommand();
    vlayer->triggerRepaint();
  }
  else
  {
    vlayer->destroyEditCommand();
  }
}

//.........这里部分代码省略.........
      {
        closePolygon();
      }

      //does compoundcurve contain circular strings?
      //does provider support circular strings?
      bool hasCurvedSegments = captureCurve()->hasCurvedSegments();
      bool providerSupportsCurvedSegments = vlayer->dataProvider()->capabilities() & QgsVectorDataProvider::CircularGeometries;

      QgsCurve *curveToAdd = nullptr;
      if ( hasCurvedSegments && providerSupportsCurvedSegments )
      {
        curveToAdd = captureCurve()->clone();
      }
      else
      {
        curveToAdd = captureCurve()->curveToLine();
      }

      vlayer->beginEditCommand( tr( "Part added" ) );
      if ( mode() == CapturePolygon )
      {
        //avoid intersections
        QgsCurvePolygon *cp = new QgsCurvePolygon();
        cp->setExteriorRing( curveToAdd );
        QgsGeometry *geom = new QgsGeometry( cp );
        geom->avoidIntersections( QgsProject::instance()->avoidIntersectionsLayers() );

        const QgsCurvePolygon *cpGeom = qgsgeometry_cast<const QgsCurvePolygon *>( geom->constGet() );
        if ( !cpGeom )
        {
          stopCapturing();
          delete geom;
          vlayer->destroyEditCommand();
          return;
        }

        errorCode = vlayer->addPart( cpGeom->exteriorRing()->clone() );
        delete geom;
      }
      else
      {
        errorCode = vlayer->addPart( curveToAdd );
      }
      stopCapturing();
    }
    break;
    default:
      Q_ASSERT( !"invalid capture mode" );
      errorCode = 6;
      break;
  }

  QString errorMessage;
  switch ( errorCode )
  {
    case 0:
    {
      // remove previous message
      emit messageDiscarded();

      //add points to other features to keep topology up-to-date
      bool topologicalEditing = QgsProject::instance()->topologicalEditing();
      if ( topologicalEditing )
      {
        addTopologicalPoints( points() );

void QgsMapToolAddFeature::canvasReleaseEvent( QMouseEvent * e )
{
  QgsDebugMsg( "entered." );

  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  QGis::WkbType layerWKBType = vlayer->wkbType();

  QgsVectorDataProvider* provider = vlayer->dataProvider();

  if ( !( provider->capabilities() & QgsVectorDataProvider::AddFeatures ) )
  {
    QMessageBox::information( 0, tr( "Layer cannot be added to" ),
                              tr( "The data provider for this layer does not support the addition of features." ) );
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  // POINT CAPTURING
  if ( mode() == CapturePoint )
  {
    //check we only use this tool for point/multipoint layers
    if ( vlayer->geometryType() != QGis::Point )
    {
      QMessageBox::information( 0, tr( "Wrong editing tool" ),
                                tr( "Cannot apply the 'capture point' tool on this vector layer" ) );
      return;
    }


    QgsPoint idPoint; //point in map coordinates
    QList<QgsSnappingResult> snapResults;
    QgsPoint savePoint; //point in layer coordinates

    if ( mSnapper.snapToBackgroundLayers( e->pos(), snapResults ) == 0 )
    {
      idPoint = snapPointFromResults( snapResults, e->pos() );
      try
      {
        savePoint = toLayerCoordinates( vlayer, idPoint );
        QgsDebugMsg( "savePoint = " + savePoint.toString() );
      }
      catch ( QgsCsException &cse )
      {
        Q_UNUSED( cse );
        QMessageBox::information( 0, tr( "Coordinate transform error" ),
                                  tr( "Cannot transform the point to the layers coordinate system" ) );
        return;
      }
    }

    //only do the rest for provider with feature addition support
    //note that for the grass provider, this will return false since
    //grass provider has its own mechanism of feature addition
    if ( provider->capabilities() & QgsVectorDataProvider::AddFeatures )
    {
      QgsFeature* f = new QgsFeature( 0, "WKBPoint" );

      QgsGeometry *g = 0;
      if ( layerWKBType == QGis::WKBPoint || layerWKBType == QGis::WKBPoint25D )
      {
        g = QgsGeometry::fromPoint( savePoint );
      }
      else if ( layerWKBType == QGis::WKBMultiPoint || layerWKBType == QGis::WKBMultiPoint25D )
      {
        g = QgsGeometry::fromMultiPoint( QgsMultiPoint() << savePoint );
      }

      f->setGeometry( g );

      vlayer->beginEditCommand( tr( "Feature added" ) );

      if ( addFeature( vlayer, f ) )
      {
        vlayer->endEditCommand();
      }
      else
      {
        delete f;
        vlayer->destroyEditCommand();
      }

      mCanvas->refresh();
    }
  }
  else if ( mode() == CaptureLine || mode() == CapturePolygon )
  {
    //check we only use the line tool for line/multiline layers
    if ( mode() == CaptureLine && vlayer->geometryType() != QGis::Line )
//.........这里部分代码省略.........

void QgsMapToolFillRing::cadCanvasReleaseEvent( QgsMapMouseEvent * e )
{
  //check if we operate on a vector layer
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->mapPoint() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      emit messageEmitted( tr( "Cannot transform the point to the layers coordinate system" ), QgsMessageBar::WARNING );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    if ( !isCapturing() )
      return;

    deleteTempRubberBand();

    closePolygon();

    vlayer->beginEditCommand( tr( "Ring added and filled" ) );
    QList< QgsPoint > pointList = points();

    QgsFeatureId modifiedFid;
    int addRingReturnCode = vlayer->addRing( pointList, &modifiedFid );
    if ( addRingReturnCode != 0 )
    {
      QString errorMessage;
      //todo: open message box to communicate errors
      if ( addRingReturnCode == 1 )
      {
        errorMessage = tr( "a problem with geometry type occured" );
      }
      else if ( addRingReturnCode == 2 )
      {
        errorMessage = tr( "the inserted Ring is not closed" );
      }
      else if ( addRingReturnCode == 3 )
      {
        errorMessage = tr( "the inserted Ring is not a valid geometry" );
      }
      else if ( addRingReturnCode == 4 )
      {
        errorMessage = tr( "the inserted Ring crosses existing rings" );
      }
      else if ( addRingReturnCode == 5 )
      {
        errorMessage = tr( "the inserted Ring is not contained in a feature" );
      }
      else
      {
        errorMessage = tr( "an unknown error occured" );
      }
      emit messageEmitted( tr( "could not add ring since %1." ).arg( errorMessage ), QgsMessageBar::CRITICAL );
      vlayer->destroyEditCommand();
    }
    else
    {
      // find parent feature and get it attributes
      double xMin, xMax, yMin, yMax;
      QgsRectangle bBox;

      xMin = std::numeric_limits<double>::max();
      xMax = -std::numeric_limits<double>::max();
      yMin = std::numeric_limits<double>::max();
      yMax = -std::numeric_limits<double>::max();

      Q_FOREACH ( const QgsPoint& point, pointList )
      {
        xMin = qMin( xMin, point.x() );
        xMax = qMax( xMax, point.x() );
        yMin = qMin( yMin, point.y() );
        yMax = qMax( yMax, point.y() );
      }

      bBox.setXMinimum( xMin );
//.........这里部分代码省略.........

void QgsMapToolAddPart::canvasReleaseEvent( QMouseEvent * e )
{
  //check if we operate on a vector layer
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );
  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //inform user at the begin of the digitising action that the island tool only works if exactly one feature is selected
  int nSelectedFeatures = vlayer->selectedFeatureCount();
  QString selectionErrorMsg;
  if ( nSelectedFeatures < 1 )
  {
    selectionErrorMsg = tr( "No feature selected. Please select a feature with the selection tool or in the attribute table" );
  }
  else if ( nSelectedFeatures > 1 )
  {
    selectionErrorMsg = tr( "Several features are selected. Please select only one feature to which an part should be added." );
  }

  if ( !selectionErrorMsg.isEmpty() )
  {
    QMessageBox::critical( 0, tr( "Error. Could not add part." ), selectionErrorMsg );
    stopCapturing();
    return;
  }

  int errorCode;
  switch ( mode() )
  {
    case CapturePoint:
    {
      QgsPoint layerPoint;
      QgsPoint mapPoint;

      if ( nextPoint( e->pos(), layerPoint, mapPoint ) != 0 )
      {
        QgsDebugMsg( "nextPoint failed" );
        return;
      }

      vlayer->beginEditCommand( tr( "Part added" ) );
      errorCode = vlayer->addPart( QList<QgsPoint>() << layerPoint );
    }
    break;

    case CaptureLine:
    case CapturePolygon:
    {
      //add point to list and to rubber band
      if ( e->button() == Qt::LeftButton )
      {
        int error = addVertex( e->pos() );
        if ( error == 1 )
        {
          QgsDebugMsg( "current layer is not a vector layer" );
          return;
        }
        else if ( error == 2 )
        {
          //problem with coordinate transformation
          QMessageBox::information( 0,
                                    tr( "Coordinate transform error" ),
                                    tr( "Cannot transform the point to the layers coordinate system" ) );
          return;
        }

        startCapturing();
        return;
      }
      else if ( e->button() != Qt::RightButton )
      {
        deleteTempRubberBand();

        return;
      }

      if ( mode() == CapturePolygon )
      {
        //close polygon
        closePolygon();
        //avoid intersections
        QgsGeometry* geom = QgsGeometry::fromPolygon( QgsPolygon() << points().toVector() );
        if ( geom )
        {
          geom->avoidIntersections();
          QgsPolygon poly = geom->asPolygon();
          if ( poly.size() < 1 )
          {
            stopCapturing();
            delete geom;
            vlayer->destroyEditCommand();
//.........这里部分代码省略.........

void QgsMapToolReshape::canvasReleaseEvent( QMouseEvent * e )
{
  //check if we operate on a vector layer //todo: move this to a function in parent class to avoid duplication
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->pos() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      QMessageBox::information( 0, tr( "Coordinate transform error" ),
                                   tr( "Cannot transform the point to the layers coordinate system" ) );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    deleteTempRubberBand();

    //find out bounding box of mCaptureList
    if ( size() < 1 )
    {
      stopCapturing();
      return;
    }
    QgsPoint firstPoint = points().at( 0 );
    QgsRectangle bbox( firstPoint.x(), firstPoint.y(), firstPoint.x(), firstPoint.y() );
    for ( int i = 1; i < size(); ++i )
    {
      bbox.combineExtentWith( points().at( i ).x(), points().at( i ).y() );
    }

    //query all the features that intersect bounding box of capture line
    QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest().setFilterRect( bbox ).setSubsetOfAttributes( QgsAttributeList() ) );
    QgsFeature f;
    int reshapeReturn;
    bool reshapeDone = false;

    vlayer->beginEditCommand( tr( "Reshape" ) );
    while ( fit.nextFeature( f ) )
    {
      //query geometry
      //call geometry->reshape(mCaptureList)
      //register changed geometry in vector layer
      QgsGeometry* geom = f.geometry();
      if ( geom )
      {
        reshapeReturn = geom->reshapeGeometry( points() );
        if ( reshapeReturn == 0 )
        {
          vlayer->changeGeometry( f.id(), geom );
          reshapeDone = true;
        }
      }
    }

    if ( reshapeDone )
    {
      vlayer->endEditCommand();
    }
    else
    {
      vlayer->destroyEditCommand();
    }

    stopCapturing();
  }
}

void QgsMapToolAddRing::canvasReleaseEvent( QMouseEvent * e )
{

  emit messageDiscarded();

  //check if we operate on a vector layer
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->pos() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      emit messageEmitted( tr( "Cannot transform the point to the layers coordinate system" ), QgsMessageBar::WARNING );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    if ( !isCapturing() )
      return;

    deleteTempRubberBand();

    closePolygon();

    vlayer->beginEditCommand( tr( "Ring added" ) );
    int addRingReturnCode = vlayer->addRing( points() );
    if ( addRingReturnCode != 0 )
    {
      QString errorMessage;
      //todo: open message box to communicate errors
      if ( addRingReturnCode == 1 )
      {
        errorMessage = tr( "a problem with geometry type occured" );
      }
      else if ( addRingReturnCode == 2 )
      {
        errorMessage = tr( "the inserted ring is not closed" );
      }
      else if ( addRingReturnCode == 3 )
      {
        errorMessage = tr( "the inserted ring is not a valid geometry" );
      }
      else if ( addRingReturnCode == 4 )
      {
        errorMessage = tr( "the inserted ring crosses existing rings" );
      }
      else if ( addRingReturnCode == 5 )
      {
        errorMessage = tr( "the inserted ring is not contained in a feature" );
      }
      else
      {
        errorMessage = tr( "an unknown error occured" );
      }
      emit messageEmitted( tr( "could not add ring since %1." ).arg( errorMessage ), QgsMessageBar::CRITICAL );
      vlayer->destroyEditCommand();
    }
    else
    {
      vlayer->endEditCommand();
    }

    stopCapturing();
  }
}

void QgsMapToolFillRing::canvasReleaseEvent( QMouseEvent * e )
{
  //check if we operate on a vector layer
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->pos() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      QMessageBox::information( 0, tr( "Coordinate transform error" ),
                                tr( "Cannot transform the point to the layers coordinate system" ) );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    deleteTempRubberBand();

    closePolygon();

    vlayer->beginEditCommand( tr( "Ring added and filled" ) );
    int addRingReturnCode = vlayer->addRing( points() );
    if ( addRingReturnCode != 0 )
    {
      QString errorMessage;
      //todo: open message box to communicate errors
      if ( addRingReturnCode == 1 )
      {
        errorMessage = tr( "A problem with geometry type occured" );
      }
      else if ( addRingReturnCode == 2 )
      {
        errorMessage = tr( "The inserted Ring is not closed" );
      }
      else if ( addRingReturnCode == 3 )
      {
        errorMessage = tr( "The inserted Ring is not a valid geometry" );
      }
      else if ( addRingReturnCode == 4 )
      {
        errorMessage = tr( "The inserted Ring crosses existing rings" );
      }
      else if ( addRingReturnCode == 5 )
      {
        errorMessage = tr( "The inserted Ring is not contained in a feature" );
      }
      else
      {
        errorMessage = tr( "An unknown error occured" );
      }
      QMessageBox::critical( 0, tr( "Error, could not add ring" ), errorMessage );
      vlayer->destroyEditCommand();
    }
    else
    {
      // find parent feature and get it attributes
      double xMin, xMax, yMin, yMax;
      QgsRectangle bBox;

      xMin = std::numeric_limits<double>::max();
      xMax = -std::numeric_limits<double>::max();
      yMin = std::numeric_limits<double>::max();
      yMax = -std::numeric_limits<double>::max();

      for ( QList<QgsPoint>::const_iterator it = points().constBegin(); it != points().constEnd(); ++it )
      {
        if ( it->x() < xMin )
        {
          xMin = it->x();
        }
        if ( it->x() > xMax )
        {
          xMax = it->x();
        }
        if ( it->y() < yMin )
        {
          yMin = it->y();
        }
//.........这里部分代码省略.........

void QgsMapToolAddRing::cadCanvasReleaseEvent( QgsMapMouseEvent * e )
{

  emit messageDiscarded();

  //check if we operate on a vector layer
  QgsVectorLayer *vlayer = currentVectorLayer();

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->mapPoint() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      emit messageEmitted( tr( "Cannot transform the point to the layers coordinate system" ), QgsMessageBar::WARNING );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    if ( !isCapturing() )
      return;

    deleteTempRubberBand();

    closePolygon();

    vlayer->beginEditCommand( tr( "Ring added" ) );

    //does compoundcurve contain circular strings?
    //does provider support circular strings?
    bool hasCurvedSegments = captureCurve()->hasCurvedSegments();
    bool providerSupportsCurvedSegments = vlayer->dataProvider()->capabilities() & QgsVectorDataProvider::CircularGeometries;

    QgsCurveV2* curveToAdd = 0;
    if ( hasCurvedSegments && providerSupportsCurvedSegments )
    {
      curveToAdd = dynamic_cast<QgsCurveV2*>( captureCurve()->clone() );
    }
    else
    {
      curveToAdd = captureCurve()->curveToLine();
    }

    int addRingReturnCode = vlayer->addRing( curveToAdd );
    if ( addRingReturnCode != 0 )
    {
      QString errorMessage;
      //todo: open message box to communicate errors
      if ( addRingReturnCode == 1 )
      {
        errorMessage = tr( "a problem with geometry type occured" );
      }
      else if ( addRingReturnCode == 2 )
      {
        errorMessage = tr( "the inserted ring is not closed" );
      }
      else if ( addRingReturnCode == 3 )
      {
        errorMessage = tr( "the inserted ring is not a valid geometry" );
      }
      else if ( addRingReturnCode == 4 )
      {
        errorMessage = tr( "the inserted ring crosses existing rings" );
      }
      else if ( addRingReturnCode == 5 )
      {
        errorMessage = tr( "the inserted ring is not contained in a feature" );
      }
      else
      {
        errorMessage = tr( "an unknown error occured" );
      }
      emit messageEmitted( tr( "could not add ring since %1." ).arg( errorMessage ), QgsMessageBar::CRITICAL );
      vlayer->destroyEditCommand();
    }
    else
    {
      vlayer->endEditCommand();
    }
//.........这里部分代码省略.........

void QgsMapToolShowHideLabels::showHideLabels( QMouseEvent * e )
{
  QgsMapLayer* layer = mCanvas->currentLayer();

  QgsVectorLayer* vlayer = dynamic_cast<QgsVectorLayer*>( layer );
  if ( !vlayer )
  {
    QgsDebugMsg( "Failed to cast label layer to vector layer" );
    return;
  }
  if ( !vlayer->isEditable() )
  {
    QgsDebugMsg( "Vector layer not editable, skipping label" );
    return;
  }

  bool doHide = e->modifiers() & Qt::ShiftModifier ? true : false;

  QgsFeatureIds selectedFeatIds;

  if ( !doHide )
  {
    QgsDebugMsg( "Showing labels operation" );

    if ( !selectedFeatures( vlayer, selectedFeatIds ) )
    {
      return;
    }
  }
  else
  {
    QgsDebugMsg( "Hiding labels operation" );

    if ( !selectedLabelFeatures( vlayer, selectedFeatIds ) )
    {
      return;
    }
  }

  QgsDebugMsg( "Number of selected labels or features: " + QString::number( selectedFeatIds.size() ) );

  if ( selectedFeatIds.isEmpty() )
  {
    return;
  }

  bool labelChanged = false;
  QString editTxt = doHide ? tr( "Hid labels" ) : tr( "Showed labels" );

  vlayer->beginEditCommand( editTxt );
  foreach ( const QgsFeatureId &fid, selectedFeatIds )
  {
    if ( showHideLabel( vlayer, fid, doHide ) )
    {
      // TODO: highlight features (maybe with QTimer?)
      labelChanged = true;
    }
  }

  if ( labelChanged )
  {
    vlayer->endEditCommand();
    mCanvas->refresh();
  }
  else
  {
    vlayer->destroyEditCommand();
  }
}

void QgsMapToolReshape::cadCanvasReleaseEvent( QgsMapMouseEvent * e )
{
  //check if we operate on a vector layer //todo: move this to a function in parent class to avoid duplication
  QgsVectorLayer *vlayer = qobject_cast<QgsVectorLayer *>( mCanvas->currentLayer() );

  if ( !vlayer )
  {
    notifyNotVectorLayer();
    return;
  }

  if ( !vlayer->isEditable() )
  {
    notifyNotEditableLayer();
    return;
  }

  //add point to list and to rubber band
  if ( e->button() == Qt::LeftButton )
  {
    int error = addVertex( e->mapPoint(), e->mapPointMatch() );
    if ( error == 1 )
    {
      //current layer is not a vector layer
      return;
    }
    else if ( error == 2 )
    {
      //problem with coordinate transformation
      emit messageEmitted( tr( "Cannot transform the point to the layers coordinate system" ), QgsMessageBar::WARNING );
      return;
    }

    startCapturing();
  }
  else if ( e->button() == Qt::RightButton )
  {
    deleteTempRubberBand();

    //find out bounding box of mCaptureList
    if ( size() < 1 )
    {
      stopCapturing();
      return;
    }
    QgsPoint firstPoint = points().at( 0 );
    QgsRectangle bbox( firstPoint.x(), firstPoint.y(), firstPoint.x(), firstPoint.y() );
    for ( int i = 1; i < size(); ++i )
    {
      bbox.combineExtentWith( points().at( i ).x(), points().at( i ).y() );
    }

    //query all the features that intersect bounding box of capture line
    QgsFeatureIterator fit = vlayer->getFeatures( QgsFeatureRequest().setFilterRect( bbox ).setSubsetOfAttributes( QgsAttributeList() ) );
    QgsFeature f;
    int reshapeReturn;
    bool reshapeDone = false;

    vlayer->beginEditCommand( tr( "Reshape" ) );
    while ( fit.nextFeature( f ) )
    {
      //query geometry
      //call geometry->reshape(mCaptureList)
      //register changed geometry in vector layer
      QgsGeometry* geom = f.geometry();
      if ( geom )
      {
        reshapeReturn = geom->reshapeGeometry( points() );
        if ( reshapeReturn == 0 )
        {
          //avoid intersections on polygon layers
          if ( vlayer->geometryType() == QGis::Polygon )
          {
            //ignore all current layer features as they should be reshaped too
            QMap<QgsVectorLayer*, QSet<QgsFeatureId> > ignoreFeatures;
            ignoreFeatures.insert( vlayer, vlayer->allFeatureIds() );

            if ( geom->avoidIntersections( ignoreFeatures ) != 0 )
            {
              emit messageEmitted( tr( "An error was reported during intersection removal" ), QgsMessageBar::CRITICAL );
              vlayer->destroyEditCommand();
              stopCapturing();
              return;
            }

            if ( geom->isGeosEmpty() ) //intersection removal might have removed the whole geometry
            {
              emit messageEmitted( tr( "The feature cannot be reshaped because the resulting geometry is empty" ), QgsMessageBar::CRITICAL );
              vlayer->destroyEditCommand();
              stopCapturing();
              return;
            }
          }

          vlayer->changeGeometry( f.id(), geom );
          reshapeDone = true;
        }
      }
    }

//.........这里部分代码省略.........

void QgsMapToolOffsetCurve::applyOffset()
{
  QgsVectorLayer* layer = currentVectorLayer();
  if ( !layer )
  {
    deleteRubberBandAndGeometry();
    notifyNotVectorLayer();
    return;
  }

  // no modification
  if ( !mGeometryModified )
  {
    deleteRubberBandAndGeometry();
    layer->destroyEditCommand();
    deleteDistanceWidget();
    return;
  }

  if ( mMultiPartGeometry )
  {
    mModifiedGeometry.convertToMultiType();
  }

  layer->beginEditCommand( tr( "Offset curve" ) );

  bool editOk;
  if ( mSourceLayerId == layer->id() && !mForceCopy )
  {
    editOk = layer->changeGeometry( mModifiedFeature, &mModifiedGeometry );
  }
  else
  {
    QgsFeature f;
    f.setGeometry( mModifiedGeometry );

    //add empty values for all fields (allows inserting attribute values via the feature form in the same session)
    QgsAttributes attrs( layer->fields().count() );
    const QgsFields& fields = layer->fields();
    for ( int idx = 0; idx < fields.count(); ++idx )
    {
      attrs[idx] = QVariant();
    }
    f.setAttributes( attrs );
    editOk = layer->addFeature( f );
  }

  if ( editOk )
  {
    layer->endEditCommand();
  }
  else
  {
    layer->destroyEditCommand();
  }

  deleteRubberBandAndGeometry();
  deleteDistanceWidget();
  delete mSnapVertexMarker;
  mSnapVertexMarker = nullptr;
  mForceCopy = false;
  mCanvas->refresh();
}