C++ VPoint::follower方法代码示例

pointlist* logicop::logic::hole2simple(const pointlist& outside, const pointlist& inside) {
   segmentlist _segl0(outside,0);
   segmentlist _segl1(inside,1);
   EventQueue* _eq = new EventQueue(_segl0, _segl1); // create the event queue
   SweepLine   _sl;
   BindCollection BC;
   _eq->swipe4bind(_sl, BC);
   BindSegment* sbc = BC.get_highest();
   //insert 2 crossing points and link them
   BPoint* cpsegA = _segl0.insertbindpoint(sbc->poly0seg(), sbc->poly0pnt());
   BPoint* cpsegB = _segl1.insertbindpoint(sbc->poly1seg(), sbc->poly1pnt());
   cpsegA->linkto(cpsegB);
   cpsegB->linkto(cpsegA);

   // normalize the segment lists
   _segl0.normalize(outside);
   _segl1.normalize(inside);
   // dump the new polygons in VList terms
   VPoint* outshape = _segl0.dump_points();
                      _segl1.dump_points();
   
   // traverse and form the resulting shape
   VPoint* centinel = outshape;
   pointlist *shgen = new pointlist();
   bool direction = true; /*next*/
   VPoint* pickup = centinel;
   VPoint* prev = centinel->prev();
   bool modify = false;
   do {
      shgen->push_back(TP(pickup->cp()->x(), pickup->cp()->y()));
      modify = (-1 == prev->visited());
      prev = pickup;
      pickup = pickup->follower(direction, modify);
   } while (pickup != centinel);

   // Validate the resulting polygon
   laydata::valid_poly check(*shgen);
//   delete shgen;
   if (!check.valid()) {
      std::ostringstream ost;
      ost << ": Resulting shape is invalid - " << check.failtype();
      tell_log(console::MT_ERROR, ost.str().c_str());
   }   
   else {
      if (laydata::shp_OK != check.status())
         *shgen = check.get_validated();
   }         
   
   return shgen;
}

/*!The method uses #_shape1 and #_shape2 structure as an input data and produces
one or more polygons representing the result of the logical AND between the 
input polygons. Method returns false if no output shapes are generated, and
true otherwise*/
bool logicop::logic::AND(pcollection& plycol) {
   bool result = false;
   VPoint* centinel = NULL;
   if (0 == _crossp) {
      // If there are no crossing points found, this still does not mean
      // that the operation will fail. Polygons might be fully overlapping...
      // Check that a random point from poly1 is inside poly2 ...
      if       (_shape1->inside(_poly2)) centinel = _shape1;
      // ... if not, check that a random point from poly2 is inside poly1 ...
      else if (_shape2->inside(_poly1)) centinel = _shape2;
      // ... if not - polygons does not have any common area
      else return false;
      // If we've got here means that one of the polygons is completely 
      // overlapped by the other one. So we need to return the inner one
      pointlist *shgen = new pointlist();
      VPoint* vpnt = centinel;
      do {
         shgen->push_back(TP(vpnt->cp()->x(), vpnt->cp()->y()));
         vpnt = vpnt->next();
      }while (centinel != vpnt);
      plycol.push_back(shgen);
      return true;
   }
   bool direction = true; /*next*/
   //if crossing points exists, get first external and non crossing  point
   centinel = getFirstOutside(_poly2, _shape1);
   if (NULL == centinel) centinel = getFirstOutside(_poly1, _shape2);
   assert(centinel);   
   VPoint* collector = centinel;
   do {
      if (0 == collector->visited()) {
         pointlist *shgen = new pointlist();
         VPoint* pickup = collector;
         do {
            pickup = pickup->follower(direction);
            shgen->push_back(TP(pickup->cp()->x(), pickup->cp()->y()));
         } while (pickup != collector);
         plycol.push_back(shgen);
         result = true;
      }
      collector = collector->prev();
   } while (collector != centinel);
   return result;
}

/*!The method uses #_shape1 and #_shape2 structure as an input data and produces
one or more polygons representing the result of the logical ANDNOT between the 
input polygons. Method returns false if no output shapes are generated, and
true otherwise*/
bool logicop::logic::ANDNOT(pcollection& plycol) {
   bool result = false;
   VPoint* centinel = NULL;
   if (0 == _crossp) {
      // If there are no crossing points found, this still does not mean
      // that the operation will fail. Polygons might be overlapping...
      // if poly1 is inside poly2, or both are non overlapping -> 
      //      resulting shape is null
      // if poly2 is inside poly1, then we have to generate a polygon
      // combining both shapes
      if (_shape2->inside(_poly1)) {
         plycol.push_back(hole2simple(_poly1, _poly2));
         return true;
      }
      else return false;
   }
   //if crossing points exists, get first external and non crossing  point
   bool direction;
   centinel = getFirstOutside(_poly1, _shape2);
   if (NULL == centinel) {
      centinel = getFirstOutside(_poly2, _shape1);
      direction = false; /*prev*/
   }
   else direction = true; /*next*/
   assert(centinel);   
   //   
   VPoint* collector = centinel;
   do {
      if (0 == collector->visited()) {
         pointlist *shgen = new pointlist();
         VPoint* pickup = collector;
         do {
            pickup = pickup->follower(direction, true);
            shgen->push_back(TP(pickup->cp()->x(), pickup->cp()->y()));
         } while (pickup != collector);
         plycol.push_back(shgen);
         result = true;
      }
      collector = collector->prev();
   } while (collector != centinel);
   return result;
}