C++ QgsSymbolV2List类代码示例

void QgsVectorLayerRenderer::drawRendererV2Levels( QgsFeatureIterator& fit )
{
  QHash< QgsSymbolV2*, QList<QgsFeature> > features; // key = symbol, value = array of features

  QgsSingleSymbolRendererV2* selRenderer = NULL;
  if ( !mSelectedFeatureIds.isEmpty() )
  {
    selRenderer = new QgsSingleSymbolRendererV2( QgsSymbolV2::defaultSymbol( mGeometryType ) );
    selRenderer->symbol()->setColor( mContext.selectionColor() );
    selRenderer->setVertexMarkerAppearance( mVertexMarkerStyle, mVertexMarkerSize );
    selRenderer->startRender( mContext, mFields );
  }

  // 1. fetch features
  QgsFeature fet;
  while ( fit.nextFeature( fet ) )
  {
    if ( !fet.geometry() )
      continue; // skip features without geometry

    if ( mContext.renderingStopped() )
    {
      qDebug( "rendering stop!" );
      stopRendererV2( selRenderer );
      return;
    }

    QgsSymbolV2* sym = mRendererV2->symbolForFeature( fet );
    if ( !sym )
    {
      continue;
    }

    if ( !features.contains( sym ) )
    {
      features.insert( sym, QList<QgsFeature>() );
    }
    features[sym].append( fet );

    if ( mCache )
    {
      // Cache this for the use of (e.g.) modifying the feature's uncommitted geometry.
      mCache->cacheGeometry( fet.id(), *fet.geometry() );
    }

    if ( sym && mContext.labelingEngine() )
    {
      if ( mLabeling )
      {
        mContext.labelingEngine()->registerFeature( mLayerID, fet, mContext );
      }
      if ( mDiagrams )
      {
        mContext.labelingEngine()->registerDiagramFeature( mLayerID, fet, mContext );
      }
    }
  }

  // find out the order
  QgsSymbolV2LevelOrder levels;
  QgsSymbolV2List symbols = mRendererV2->symbols();
  for ( int i = 0; i < symbols.count(); i++ )
  {
    QgsSymbolV2* sym = symbols[i];
    for ( int j = 0; j < sym->symbolLayerCount(); j++ )
    {
      int level = sym->symbolLayer( j )->renderingPass();
      if ( level < 0 || level >= 1000 ) // ignore invalid levels
        continue;
      QgsSymbolV2LevelItem item( sym, j );
      while ( level >= levels.count() ) // append new empty levels
        levels.append( QgsSymbolV2Level() );
      levels[level].append( item );
    }
  }

  // 2. draw features in correct order
  for ( int l = 0; l < levels.count(); l++ )
  {
    QgsSymbolV2Level& level = levels[l];
    for ( int i = 0; i < level.count(); i++ )
    {
      QgsSymbolV2LevelItem& item = level[i];
      if ( !features.contains( item.symbol() ) )
      {
        QgsDebugMsg( "level item's symbol not found!" );
        continue;
      }
      int layer = item.layer();
      QList<QgsFeature>& lst = features[item.symbol()];
      QList<QgsFeature>::iterator fit;
      for ( fit = lst.begin(); fit != lst.end(); ++fit )
      {
        if ( mContext.renderingStopped() )
        {
          stopRendererV2( selRenderer );
          return;
        }

        bool sel = mSelectedFeatureIds.contains( fit->id() );
//.........这里部分代码省略.........

QgsSymbolV2List QgsSingleSymbolRendererV2::symbols()
{
  QgsSymbolV2List lst;
  lst.append( mSymbol.data() );
  return lst;
}

void QgsDxfExport::writeEntitiesSymbolLevels( QgsVectorLayer* layer )
{
  if ( !layer )
  {
    return;
  }

  QgsFeatureRendererV2* renderer = layer->rendererV2();
  if ( !renderer )
  {
    //return error
  }
  QHash< QgsSymbolV2*, QList<QgsFeature> > features;

  QgsRenderContext ctx = renderContext();
  QgsSymbolV2RenderContext sctx( ctx, QgsSymbolV2::MM , 1.0, false, 0, 0 );
  renderer->startRender( ctx, layer->pendingFields() );

  //get iterator
  QgsFeatureRequest req;
  if ( layer->wkbType() == QGis::WKBNoGeometry )
  {
    req.setFlags( QgsFeatureRequest::NoGeometry );
  }
  req.setSubsetOfAttributes( QStringList( renderer->usedAttributes() ), layer->pendingFields() );
  if ( !mExtent.isEmpty() )
  {
    req.setFilterRect( mExtent );
  }
  QgsFeatureIterator fit = layer->getFeatures( req );

  //fetch features
  QgsFeature fet;
  QgsSymbolV2* featureSymbol = 0;
  while ( fit.nextFeature( fet ) )
  {
    featureSymbol = renderer->symbolForFeature( fet );
    if ( !featureSymbol )
    {
      continue;
    }

    QHash< QgsSymbolV2*, QList<QgsFeature> >::iterator it = features.find( featureSymbol );
    if ( it == features.end() )
    {
      it = features.insert( featureSymbol, QList<QgsFeature>() );
    }
    it.value().append( fet );
  }

  //find out order
  QgsSymbolV2LevelOrder levels;
  QgsSymbolV2List symbols = renderer->symbols();
  for ( int i = 0; i < symbols.count(); i++ )
  {
    QgsSymbolV2* sym = symbols[i];
    for ( int j = 0; j < sym->symbolLayerCount(); j++ )
    {
      int level = sym->symbolLayer( j )->renderingPass();
      if ( level < 0 || level >= 1000 ) // ignore invalid levels
        continue;
      QgsSymbolV2LevelItem item( sym, j );
      while ( level >= levels.count() ) // append new empty levels
        levels.append( QgsSymbolV2Level() );
      levels[level].append( item );
    }
  }

  //export symbol layers and symbology
  for ( int l = 0; l < levels.count(); l++ )
  {
    QgsSymbolV2Level& level = levels[l];
    for ( int i = 0; i < level.count(); i++ )
    {
      QgsSymbolV2LevelItem& item = level[i];
      QHash< QgsSymbolV2*, QList<QgsFeature> >::iterator levelIt = features.find( item.symbol() );

      int llayer = item.layer();
      QList<QgsFeature>& featureList = levelIt.value();
      QList<QgsFeature>::iterator featureIt = featureList.begin();
      for ( ; featureIt != featureList.end(); ++featureIt )
      {
        addFeature( sctx, layer->name(), levelIt.key()->symbolLayer( llayer ), levelIt.key() );
      }
    }
  }
  renderer->stopRender( ctx );
}

void QgsVectorLayerRenderer::drawRendererV2( QgsFeatureIterator& fit )
{
  QgsExpressionContextScope* symbolScope = QgsExpressionContextUtils::updateSymbolScope( nullptr, new QgsExpressionContextScope() );
  mContext.expressionContext().appendScope( symbolScope );

  QgsFeature fet;
  while ( fit.nextFeature( fet ) )
  {
    try
    {
      if ( mContext.renderingStopped() )
      {
        QgsDebugMsg( QString( "Drawing of vector layer %1 cancelled." ).arg( layerID() ) );
        break;
      }

      if ( !fet.constGeometry() )
        continue; // skip features without geometry

      mContext.expressionContext().setFeature( fet );

      bool sel = mContext.showSelection() && mSelectedFeatureIds.contains( fet.id() );
      bool drawMarker = ( mDrawVertexMarkers && mContext.drawEditingInformation() && ( !mVertexMarkerOnlyForSelection || sel ) );

      if ( mCache )
      {
        // Cache this for the use of (e.g.) modifying the feature's uncommitted geometry.
        mCache->cacheGeometry( fet.id(), *fet.constGeometry() );
      }

      // render feature
      bool rendered = mRendererV2->renderFeature( fet, mContext, -1, sel, drawMarker );

      // labeling - register feature
      if ( rendered )
      {
        if ( mContext.labelingEngine() )
        {
          if ( mLabeling )
          {
            mContext.labelingEngine()->registerFeature( mLayerID, fet, mContext );
          }
          if ( mDiagrams )
          {
            mContext.labelingEngine()->registerDiagramFeature( mLayerID, fet, mContext );
          }
        }
        // new labeling engine
        if ( mContext.labelingEngineV2() )
        {
          QScopedPointer<QgsGeometry> obstacleGeometry;
          QgsSymbolV2List symbols = mRendererV2->originalSymbolsForFeature( fet, mContext );

          if ( !symbols.isEmpty() && fet.constGeometry()->type() == QGis::Point )
          {
            obstacleGeometry.reset( QgsVectorLayerLabelProvider::getPointObstacleGeometry( fet, mContext, symbols ) );
          }

          if ( !symbols.isEmpty() )
          {
            QgsExpressionContextUtils::updateSymbolScope( symbols.at( 0 ), symbolScope );
          }

          if ( mLabelProvider )
          {
            mLabelProvider->registerFeature( fet, mContext, obstacleGeometry.data() );
          }
          if ( mDiagramProvider )
          {
            mDiagramProvider->registerFeature( fet, mContext, obstacleGeometry.data() );
          }
        }
      }
    }
    catch ( const QgsCsException &cse )
    {
      Q_UNUSED( cse );
      QgsDebugMsg( QString( "Failed to transform a point while drawing a feature with ID '%1'. Ignoring this feature. %2" )
                   .arg( fet.id() ).arg( cse.what() ) );
    }
  }

  delete mContext.expressionContext().popScope();

  stopRendererV2( nullptr );
}

void QgsDxfExport::writeEntities()
{
  startSection();
  writeGroup( 2, "ENTITIES" );

  //label engine
  QgsDxfPalLabeling labelEngine( this, mExtent.isEmpty() ? dxfExtent() : mExtent, mSymbologyScaleDenominator, mMapUnits );
  QgsRenderContext& ctx = labelEngine.renderContext();

  //iterate through the maplayers
  QList< QgsMapLayer* >::iterator layerIt = mLayers.begin();
  for ( ; layerIt != mLayers.end(); ++layerIt )
  {
    QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( *layerIt );
    if ( !vl || !layerIsScaleBasedVisible( vl ) )
    {
      continue;
    }

    QgsSymbolV2RenderContext sctx( ctx, QgsSymbolV2::MM , 1.0, false, 0, 0 );
    QgsFeatureRendererV2* renderer = vl->rendererV2();
    renderer->startRender( ctx, vl->pendingFields() );

    QStringList attributes = renderer->usedAttributes();

    bool labelLayer = ( labelEngine.prepareLayer( vl, attributes, ctx ) != 0 );

    if ( mSymbologyExport == QgsDxfExport::SymbolLayerSymbology && ( renderer->capabilities() & QgsFeatureRendererV2::SymbolLevels ) &&
         renderer->usingSymbolLevels() )
    {
      writeEntitiesSymbolLevels( vl );
      renderer->stopRender( ctx );
      continue;
    }

    QgsFeatureRequest freq = QgsFeatureRequest().setSubsetOfAttributes(
                               attributes, vl->pendingFields() );
    if ( !mExtent.isEmpty() )
    {
      freq.setFilterRect( mExtent );
    }
    QgsFeatureIterator featureIt = vl->getFeatures( freq );
    QgsFeature fet;
    while ( featureIt.nextFeature( fet ) )
    {
      sctx.setFeature( &fet );
      if ( mSymbologyExport == NoSymbology )
      {
        addFeature( sctx, dxfLayerName( vl->name() ), 0, 0 ); //no symbology at all
      }
      else
      {
        if ( !renderer )
        {
          continue;
        }
        QgsSymbolV2List symbolList = renderer->symbolsForFeature( fet );
        if ( symbolList.size() < 1 )
        {
          continue;
        }

        if ( mSymbologyExport == QgsDxfExport::SymbolLayerSymbology ) //symbol layer symbology, but layer does not use symbol levels
        {
          QgsSymbolV2List::iterator symbolIt = symbolList.begin();
          for ( ; symbolIt != symbolList.end(); ++symbolIt )
          {
            int nSymbolLayers = ( *symbolIt )->symbolLayerCount();
            for ( int i = 0; i < nSymbolLayers; ++i )
            {
              addFeature( sctx, dxfLayerName( vl->name() ), ( *symbolIt )->symbolLayer( i ), *symbolIt );
            }
          }
        }
        else
        {
          //take first symbollayer from first symbol
          QgsSymbolV2* s = symbolList.first();
          if ( !s || s->symbolLayerCount() < 1 )
          {
            continue;
          }
          addFeature( sctx, dxfLayerName( vl->name() ), s->symbolLayer( 0 ), s );
        }

        if ( labelLayer )
        {
          labelEngine.registerFeature( vl->id(), fet, ctx );
        }
      }
    }
    renderer->stopRender( ctx );
  }

  labelEngine.drawLabeling( ctx );
  endSection();
}