src/SketchPlugin/SketchPlugin_Offset.cpp

   1 // Copyright (C) 2020  CEA/DEN, EDF R&D
   2 //
   3 // This library is free software; you can redistribute it and/or
   4 // modify it under the terms of the GNU Lesser General Public
   5 // License as published by the Free Software Foundation; either
   6 // version 2.1 of the License, or (at your option) any later version.
   7 //
   8 // This library is distributed in the hope that it will be useful,
   9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11 // Lesser General Public License for more details.
  12 //
  13 // You should have received a copy of the GNU Lesser General Public
  14 // License along with this library; if not, write to the Free Software
  15 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  16 //
  17 // See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
  18 //
  19
  20 #include <SketchPlugin_Offset.h>
  21
  22 #include <SketchPlugin_Sketch.h>
  23 #include <SketchPlugin_Line.h>
  24 #include <SketchPlugin_Point.h>
  25 #include <SketchPlugin_Arc.h>
  26 #include <SketchPlugin_Circle.h>
  27 #include <SketchPlugin_Ellipse.h>
  28 #include <SketchPlugin_EllipticArc.h>
  29 #include <SketchPlugin_BSpline.h>
  30 #include <SketchPlugin_BSplinePeriodic.h>
  31 #include <SketchPlugin_Tools.h>
  32
  33 #include <Events_InfoMessage.h>
  34
  35 #include <ModelAPI_AttributeBoolean.h>
  36 #include <ModelAPI_AttributeDouble.h>
  37 #include <ModelAPI_AttributeDoubleArray.h>
  38 #include <ModelAPI_AttributeInteger.h>
  39 #include <ModelAPI_AttributeRefList.h>
  40 #include <ModelAPI_ResultConstruction.h>
  41 #include <ModelAPI_Tools.h>
  42
  43 #include <GeomAlgoAPI_Offset.h>
  44 #include <GeomAlgoAPI_ShapeTools.h>
  45 #include <GeomAlgoAPI_WireBuilder.h>
  46
  47 #include <GeomAPI_Edge.h>
  48 #include <GeomAPI_Circ.h>
  49 #include <GeomAPI_Ellipse.h>
  50 #include <GeomAPI_BSpline.h>
  51
  52 #include <GeomDataAPI_Point2D.h>
  53 #include <GeomDataAPI_Point2DArray.h>
  54
  55 #include <iostream>
  56
  57 SketchPlugin_Offset::SketchPlugin_Offset()
  58   : SketchPlugin_SketchEntity()
  59 {
  60 }
  61
  62 void SketchPlugin_Offset::initDerivedClassAttributes()
  63 {
  64   data()->addAttribute(EDGES_ID(), ModelAPI_AttributeRefList::typeId());
  65   data()->addAttribute(VALUE_ID(), ModelAPI_AttributeDouble::typeId());
  66   data()->addAttribute(REVERSED_ID(), ModelAPI_AttributeBoolean::typeId());
  67 }
  68
  69 void SketchPlugin_Offset::execute()
  70 {
  71   ModelAPI_Tools::removeFeaturesAndReferences(myCreatedFeatures);
  72   myCreatedFeatures.clear();
  73
  74   SketchPlugin_Sketch* aSketch = sketch();
  75   if (!aSketch) return;
  76
  77   // 1. Sketch plane
  78   std::shared_ptr<GeomAPI_Pln> aPlane = aSketch->plane();
  79
  80   // 2. Offset value
  81   AttributeDoublePtr aValueAttr = real(VALUE_ID());
  82   if (!aValueAttr->isInitialized()) return;
  83   double aValue = aValueAttr->value();
  84   const double tolerance = 1.e-7;
  85   if (aValue < tolerance) return;
  86
  87   // 2.a. Reversed?
  88   AttributeBooleanPtr aReversedAttr = boolean(REVERSED_ID());
  89   if (!aReversedAttr->isInitialized()) return;
  90   if (aReversedAttr->value()) aValue = -aValue; // reverse offset direction
  91
  92   // 3. List of all selected edges
  93   AttributeRefListPtr aSelectedEdges = reflist(EDGES_ID());
  94   std::list<ObjectPtr> anEdgesList = aSelectedEdges->list();
  95
  96   // 4. Put all selected edges in a set to pass them into findWireOneWay() below
  97   std::set<FeaturePtr> anEdgesSet;
  98   std::list<ObjectPtr>::const_iterator anEdgesIt = anEdgesList.begin();
  99   for (; anEdgesIt != anEdgesList.end(); anEdgesIt++) {
 100     FeaturePtr aFeature = ModelAPI_Feature::feature(*anEdgesIt);
 101     if (aFeature) {
 102       anEdgesSet.insert(aFeature);
 103     }
 104   }
 105
 106   // 5. Gather wires and make offset for each wire
 107   for (anEdgesIt = anEdgesList.begin(); anEdgesIt != anEdgesList.end(); anEdgesIt++) {
 108     FeaturePtr aFeature = ModelAPI_Feature::feature(*anEdgesIt);
 109     if (aFeature.get()) {
 110       if (anEdgesSet.find(aFeature) == anEdgesSet.end())
 111         continue;
 112
 113       // 5.a. End points (if any)
 114       std::shared_ptr<GeomDataAPI_Point2D> aStartPoint, anEndPoint;
 115       SketchPlugin_SegmentationTools::getFeaturePoints(aFeature, aStartPoint, anEndPoint);
 116
 117       // 5.b. Find a chain of edges
 118       std::list<FeaturePtr> aChain;
 119       aChain.push_back(aFeature);
 120       if (aStartPoint && anEndPoint) { // not closed edge
 121         bool isClosed = findWireOneWay(aFeature, aFeature, aStartPoint, anEdgesSet, aChain);
 122         if (!isClosed)
 123           findWireOneWay(aFeature, aFeature, anEndPoint, anEdgesSet, aChain);
 124       }
 125       std::set<FeaturePtr>::iterator aPos = anEdgesSet.find(aFeature);
 126       if (aPos != anEdgesSet.end())
 127         anEdgesSet.erase(aPos);
 128
 129       // 5.c. Make wire
 130       ListOfShape aTopoChain;
 131       std::list<FeaturePtr>::iterator aChainIt = aChain.begin();
 132       for (; aChainIt != aChain.end(); ++aChainIt) {
 133         FeaturePtr aChainFeature = (*aChainIt);
 134         GeomShapePtr aTopoEdge = aChainFeature->lastResult()->shape();
 135         if (aTopoEdge->shapeType() == GeomAPI_Shape::EDGE) {
 136           aTopoChain.push_back(aTopoEdge);
 137         }
 138       }
 139       GeomShapePtr anEdgeOrWire = GeomAlgoAPI_WireBuilder::wire(aTopoChain);
 140
 141       // 5.d. Make offset for each wire
 142       std::shared_ptr<GeomAPI_Shape> anOffsetShape =
 143         GeomAlgoAPI_Offset::OffsetInPlane(aPlane, anEdgeOrWire, aValue);
 144
 145       // 5.e. Store offset results.
 146       //      Create sketch feature for each edge of anOffsetShape, and also store
 147       //      created features in myCreatedFeatures to remove them on next execute()
 148       addToSketch(anOffsetShape);
 149     }
 150   }
 151 }
 152
 153 bool SketchPlugin_Offset::findWireOneWay (const FeaturePtr& theFirstEdge,
 154                                           const FeaturePtr& theEdge,
 155                                           const std::shared_ptr<GeomDataAPI_Point2D>& theEndPoint,
 156                                           std::set<FeaturePtr>& theEdgesSet,
 157                                           std::list<FeaturePtr>& theChain)
 158 {
 159   // 1. Find a single edge, coincident to theEndPoint by one of its ends
 160   if (!theEndPoint) return false;
 161
 162   std::shared_ptr<GeomAPI_Pnt2d> aP2d = theEndPoint->pnt();
 163
 164   FeaturePtr aNextEdgeFeature;
 165   int nbFound = 0;
 166
 167   std::set<AttributePoint2DPtr> aCoincPoints;
 168   std::map<AttributePoint2DArrayPtr, int> aCoincPointsInArray;
 169   SketchPlugin_Tools::findPointsCoincidentToPoint(theEndPoint, aCoincPoints, aCoincPointsInArray);
 170
 171   // store all found attributes to a single array
 172   std::set<AttributePtr> anAllCoincPoints;
 173   anAllCoincPoints.insert(aCoincPoints.begin(), aCoincPoints.end());
 174   for (auto it = aCoincPointsInArray.begin(); it != aCoincPointsInArray.end(); ++it)
 175     anAllCoincPoints.insert(it->first);
 176
 177   std::set<AttributePtr>::iterator aPointsIt = anAllCoincPoints.begin();
 178   for (; aPointsIt != anAllCoincPoints.end(); aPointsIt++) {
 179     AttributePtr aP = (*aPointsIt);
 180     FeaturePtr aCoincFeature = std::dynamic_pointer_cast<ModelAPI_Feature>(aP->owner());
 181
 182     // Condition 1: not a point feature
 183     if (aCoincFeature->getKind() != SketchPlugin_Point::ID()) {
 184       // Condition 2: it is not the current edge
 185       if (aCoincFeature != theEdge) {
 186         // Condition 3: it is in the set of interest.
 187         //              Empty set means all sketch edges.
 188         bool isInSet = true;
 189         if (theEdgesSet.size()) {
 190           isInSet = (theEdgesSet.find(aCoincFeature) != theEdgesSet.end());
 191         }
 192         if (isInSet) {
 193           // Condition 4: consider only features with two end points
 194           std::shared_ptr<GeomDataAPI_Point2D> aP1, aP2;
 195           SketchPlugin_SegmentationTools::getFeaturePoints(aCoincFeature, aP1, aP2);
 196           if (aP1 && aP2) {
 197             // Condition 5: consider only features, that have aP as one of they ends.
 198             //              For example, we do not need an arc, coincident to aP by its center.
 199             if (theEndPoint->pnt()->isEqual(aP1->pnt()) ||
 200                 theEndPoint->pnt()->isEqual(aP2->pnt())) {
 201               // Condition 6: only one edge can prolongate the chain. If several, we stop here.
 202               nbFound++;
 203               if (nbFound > 1)
 204                 return false;
 205
 206               // One found
 207               aNextEdgeFeature = aCoincFeature;
 208             }
 209           }
 210         }
 211       }
 212     }
 213   }
 214
 215   // Only one edge can prolongate the chain. If several or none, we stop here.
 216   if (nbFound != 1)
 217     return false;
 218
 219   // 2. So, we have the single edge, that prolongate the chain
 220
 221   // Condition 7: if we reached the very first edge of the chain
 222   if (aNextEdgeFeature == theFirstEdge)
 223     // Closed chain found
 224     return true;
 225
 226   // 3. Add the found edge to the chain
 227   theChain.push_back(aNextEdgeFeature);
 228   // remove from the set, if the set is used
 229   if (theEdgesSet.size()) {
 230     std::set<FeaturePtr>::iterator aPos = theEdgesSet.find(aNextEdgeFeature);
 231     if (aPos != theEdgesSet.end())
 232       theEdgesSet.erase(aPos);
 233   }
 234
 235   // 4. Which end of aNextEdgeFeature we need to proceed
 236   std::shared_ptr<GeomDataAPI_Point2D> aP1, aP2;
 237   SketchPlugin_SegmentationTools::getFeaturePoints(aNextEdgeFeature, aP1, aP2);
 238   if (aP2->pnt()->isEqual(theEndPoint->pnt())) {
 239     // reversed
 240     aP2 = aP1;
 241   }
 242
 243   // 5. Continue gathering the chain (recursive)
 244   return findWireOneWay (theFirstEdge, aNextEdgeFeature, aP2, theEdgesSet, theChain);
 245 }
 246
 247 void SketchPlugin_Offset::addToSketch(const std::shared_ptr<GeomAPI_Shape>& anOffsetShape)
 248 {
 249   //GeomAPI_ShapeExplorer::GeomAPI_ShapeExplorer
 250   ListOfShape aResEdges = GeomAlgoAPI_ShapeTools::getLowLevelSubShapes(anOffsetShape);
 251   std::list<GeomShapePtr>::const_iterator aResEdgesIt = aResEdges.begin();
 252   for (; aResEdgesIt != aResEdges.end(); aResEdgesIt++) {
 253     GeomShapePtr aResShape = (*aResEdgesIt);
 254     if (aResShape->shapeType() == GeomAPI_Shape::EDGE) {
 255       // Add new feature
 256       FeaturePtr aResFeature;
 257       std::shared_ptr<GeomAPI_Edge> aResEdge (new GeomAPI_Edge(aResShape));
 258
 259       std::shared_ptr<GeomAPI_Pnt2d> aFP, aLP;
 260       std::shared_ptr<GeomAPI_Pnt> aFP3d = aResEdge->firstPoint();
 261       std::shared_ptr<GeomAPI_Pnt> aLP3d = aResEdge->lastPoint();
 262       //if (aFP3d.get() && aLP3d.get()) {
 263       if (aFP3d && aLP3d) {
 264         aFP = sketch()->to2D(aFP3d);
 265         aLP = sketch()->to2D(aLP3d);
 266       }
 267
 268       if (aResEdge->isLine()) {
 269         aResFeature = sketch()->addFeature(SketchPlugin_Line::ID());
 270
 271         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 272           (aResFeature->attribute(SketchPlugin_Line::START_ID()))->setValue(aFP);
 273         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 274           (aResFeature->attribute(SketchPlugin_Line::END_ID()))->setValue(aLP);
 275       }
 276       else if (aResEdge->isArc()) {
 277         std::shared_ptr<GeomAPI_Circ> aCircEdge = aResEdge->circle();
 278         std::shared_ptr<GeomAPI_Pnt> aCP3d = aCircEdge->center();
 279         std::shared_ptr<GeomAPI_Pnt2d> aCP = sketch()->to2D(aCP3d);
 280
 281         aResFeature = sketch()->addFeature(SketchPlugin_Arc::ID());
 282
 283         bool aWasBlocked = aResFeature->data()->blockSendAttributeUpdated(true);
 284         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 285           (aResFeature->attribute(SketchPlugin_Arc::CENTER_ID()))->setValue(aCP);
 286         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 287           (aResFeature->attribute(SketchPlugin_Arc::START_ID()))->setValue(aFP);
 288         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 289           (aResFeature->attribute(SketchPlugin_Arc::END_ID()))->setValue(aLP);
 290         aResFeature->data()->blockSendAttributeUpdated(aWasBlocked);
 291       }
 292       else if (aResEdge->isCircle()) {
 293         std::shared_ptr<GeomAPI_Circ> aCircEdge = aResEdge->circle();
 294         std::shared_ptr<GeomAPI_Pnt> aCP3d = aCircEdge->center();
 295         std::shared_ptr<GeomAPI_Pnt2d> aCP = sketch()->to2D(aCP3d);
 296
 297         aResFeature = sketch()->addFeature(SketchPlugin_Circle::ID());
 298         std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 299           (aResFeature->attribute(SketchPlugin_Circle::CENTER_ID()))->setValue(aCP);
 300         aResFeature->real(SketchPlugin_Circle::RADIUS_ID())->setValue(aCircEdge->radius());
 301       }
 302       else if (aResEdge->isEllipse()) {
 303         std::shared_ptr<GeomAPI_Ellipse> anEllipseEdge = aResEdge->ellipse();
 304
 305         GeomPointPtr aCP3d = anEllipseEdge->center();
 306         GeomPnt2dPtr aCP = sketch()->to2D(aCP3d);
 307
 308         GeomPointPtr aFocus3d = anEllipseEdge->firstFocus();
 309         GeomPnt2dPtr aFocus = sketch()->to2D(aFocus3d);
 310
 311         if (aFP3d && aLP3d) {
 312           // Elliptic arc
 313           aResFeature = sketch()->addFeature(SketchPlugin_EllipticArc::ID());
 314
 315           bool aWasBlocked = aResFeature->data()->blockSendAttributeUpdated(true);
 316           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 317             (aResFeature->attribute(SketchPlugin_EllipticArc::CENTER_ID()))->setValue(aCP);
 318           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 319             (aResFeature->attribute(SketchPlugin_EllipticArc::FIRST_FOCUS_ID()))->setValue(aFocus);
 320           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 321             (aResFeature->attribute(SketchPlugin_EllipticArc::START_POINT_ID()))->setValue(aFP);
 322           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 323             (aResFeature->attribute(SketchPlugin_EllipticArc::END_POINT_ID()))->setValue(aLP);
 324           aResFeature->data()->blockSendAttributeUpdated(aWasBlocked);
 325         }
 326         else {
 327           // Ellipse
 328           aResFeature = sketch()->addFeature(SketchPlugin_Ellipse::ID());
 329
 330           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 331             (aResFeature->attribute(SketchPlugin_Ellipse::CENTER_ID()))->setValue(aCP);
 332           std::dynamic_pointer_cast<GeomDataAPI_Point2D>
 333             (aResFeature->attribute(SketchPlugin_Ellipse::FIRST_FOCUS_ID()))->setValue(aFocus);
 334           aResFeature->real(SketchPlugin_Ellipse::MINOR_RADIUS_ID())->setValue(anEllipseEdge->minorRadius());
 335         }
 336       }
 337       else if (aResEdge->isBSpline()) {
 338         mkBSpline(aResFeature, aResEdge);
 339       }
 340       else {
 341       }
 342
 343       if (aResFeature.get()) {
 344         myCreatedFeatures.insert(aResFeature);
 345
 346         aResFeature->boolean(SketchPlugin_SketchEntity::AUXILIARY_ID())->setValue
 347           (boolean(SketchPlugin_SketchEntity::AUXILIARY_ID())->value());
 348         aResFeature->execute();
 349       }
 350     }
 351   }
 352 }
 353
 354 void SketchPlugin_Offset::mkBSpline (FeaturePtr& theResult,
 355                                      const GeomEdgePtr& theEdge)
 356 {
 357   if (!theEdge->isBSpline())
 358     return;
 359
 360   GeomCurvePtr aCurve (new GeomAPI_Curve (theEdge));
 361   GeomAPI_BSpline aBSpline (aCurve);
 362
 363   if (aBSpline.isPeriodic())
 364     theResult = sketch()->addFeature(SketchPlugin_BSplinePeriodic::ID());
 365   else
 366     theResult = sketch()->addFeature(SketchPlugin_BSpline::ID());
 367
 368   theResult->integer(SketchPlugin_BSpline::DEGREE_ID())->setValue(aBSpline.degree());
 369
 370   AttributePoint2DArrayPtr aPolesAttr = std::dynamic_pointer_cast<GeomDataAPI_Point2DArray>
 371     (theResult->attribute(SketchPlugin_BSpline::POLES_ID()));
 372   std::list<GeomPointPtr> aPoles = aBSpline.poles();
 373   aPolesAttr->setSize((int)aPoles.size());
 374   std::list<GeomPointPtr>::iterator anIt = aPoles.begin();
 375   for (int anIndex = 0; anIt != aPoles.end(); ++anIt, ++anIndex) {
 376     GeomPnt2dPtr aPoleInSketch = sketch()->to2D(*anIt);
 377     aPolesAttr->setPnt(anIndex, aPoleInSketch);
 378   }
 379
 380   AttributeDoubleArrayPtr aWeightsAttr =
 381       theResult->data()->realArray(SketchPlugin_BSpline::WEIGHTS_ID());
 382   std::list<double> aWeights = aBSpline.weights();
 383   if (aWeights.empty()) { // rational B-spline
 384     int aSize = (int)aPoles.size();
 385     aWeightsAttr->setSize(aSize);
 386     for (int anIndex = 0; anIndex < aSize; ++anIndex)
 387       aWeightsAttr->setValue(anIndex, 1.0);
 388   }
 389   else { // non-rational B-spline
 390     aWeightsAttr->setSize((int)aWeights.size());
 391     std::list<double>::iterator anIt = aWeights.begin();
 392     for (int anIndex = 0; anIt != aWeights.end(); ++anIt, ++anIndex)
 393       aWeightsAttr->setValue(anIndex, *anIt);
 394   }
 395
 396   AttributeDoubleArrayPtr aKnotsAttr =
 397       theResult->data()->realArray(SketchPlugin_BSpline::KNOTS_ID());
 398   std::list<double> aKnots = aBSpline.knots();
 399   int aSize = (int)aKnots.size();
 400   aKnotsAttr->setSize(aSize);
 401   std::list<double>::iterator aKIt = aKnots.begin();
 402   for (int index = 0; index < aSize; ++index, ++aKIt)
 403     aKnotsAttr->setValue(index, *aKIt);
 404
 405   AttributeIntArrayPtr aMultsAttr =
 406       theResult->data()->intArray(SketchPlugin_BSpline::MULTS_ID());
 407   std::list<int> aMultiplicities = aBSpline.mults();
 408   aSize = (int)aMultiplicities.size();
 409   aMultsAttr->setSize(aSize);
 410   std::list<int>::iterator aMIt = aMultiplicities.begin();
 411   for (int index = 0; index < aSize; ++index, ++aMIt)
 412     aMultsAttr->setValue(index, *aMIt);
 413 }
 414
 415 void SketchPlugin_Offset::attributeChanged(const std::string& theID)
 416 {
 417   ModelAPI_Tools::removeFeaturesAndReferences(myCreatedFeatures);
 418   myCreatedFeatures.clear();
 419 }
 420
 421 bool SketchPlugin_Offset::customAction(const std::string& theActionId)
 422 {
 423   bool isOk = false;
 424   if (theActionId == ADD_WIRE_ACTION_ID()) {
 425     isOk = findWires();
 426   }
 427   else {
 428     std::string aMsg = "Error: Feature \"%1\" does not support action \"%2\".";
 429     Events_InfoMessage("SketchPlugin_Offset", aMsg).arg(getKind()).arg(theActionId).send();
 430   }
 431   return isOk;
 432 }
 433
 434 bool SketchPlugin_Offset::findWires()
 435 {
 436   AttributeRefListPtr aSelectedEdges = reflist(EDGES_ID());
 437   std::list<ObjectPtr> anEdgesList = aSelectedEdges->list();
 438
 439   // Empty set
 440   std::set<FeaturePtr> anEdgesSet;
 441
 442   // Processed set
 443   std::set<FeaturePtr> aProcessedSet;
 444
 445   // Put all selected edges in a set to avoid adding them in reflist(EDGES_ID())
 446   std::set<FeaturePtr> aSelectedSet;
 447   std::list<ObjectPtr>::const_iterator anEdgesIt = anEdgesList.begin();
 448   for (; anEdgesIt != anEdgesList.end(); anEdgesIt++) {
 449     FeaturePtr aFeature = ModelAPI_Feature::feature(*anEdgesIt);
 450     if (aFeature) {
 451       aSelectedSet.insert(aFeature);
 452     }
 453   }
 454
 455   // Gather chains of edges
 456   for (anEdgesIt = anEdgesList.begin(); anEdgesIt != anEdgesList.end(); anEdgesIt++) {
 457     FeaturePtr aFeature = ModelAPI_Feature::feature(*anEdgesIt);
 458     if (aFeature.get()) {
 459       if (aProcessedSet.find(aFeature) != aProcessedSet.end())
 460         continue;
 461       aProcessedSet.insert(aFeature);
 462
 463       // End points (if any)
 464       std::shared_ptr<GeomDataAPI_Point2D> aStartPoint, anEndPoint;
 465       SketchPlugin_SegmentationTools::getFeaturePoints(aFeature, aStartPoint, anEndPoint);
 466
 467       std::list<FeaturePtr> aChain;
 468       aChain.push_back(aFeature);
 469       bool isClosed = findWireOneWay(aFeature, aFeature, aStartPoint, anEdgesSet, aChain);
 470       if (!isClosed)
 471         findWireOneWay(aFeature, aFeature, anEndPoint, anEdgesSet, aChain);
 472
 473       std::list<FeaturePtr>::iterator aChainIt = aChain.begin();
 474       for (; aChainIt != aChain.end(); ++aChainIt) {
 475         FeaturePtr aChainFeature = (*aChainIt);
 476         aProcessedSet.insert(aChainFeature);
 477         if (aSelectedSet.find(aChainFeature) == aSelectedSet.end()) {
 478           aSelectedEdges->append(aChainFeature->lastResult());
 479         }
 480       }
 481     }
 482   }
 483   // TODO: hilight selection in the viewer
 484
 485   return true;
 486 }