C++ Polylines::push_back方法代码示例

Polylines PolylineCollection::_chained_path_from(
    const Polylines &src,
    Point start_near,
    bool  no_reverse, 
    bool  move_from_src)
{
    std::vector<Chaining> endpoints;
    endpoints.reserve(src.size());
    for (size_t i = 0; i < src.size(); ++ i) {
        Chaining c;
        c.first = src[i].first_point();
        if (! no_reverse)
            c.last = src[i].last_point();
        c.idx = i;
        endpoints.push_back(c);
    }
    Polylines retval;
    while (! endpoints.empty()) {
        // find nearest point
        int endpoint_index = nearest_point_index<double>(endpoints, start_near, no_reverse);
        assert(endpoint_index >= 0 && endpoint_index < endpoints.size() * 2);
        if (move_from_src) {
            retval.push_back(std::move(src[endpoints[endpoint_index/2].idx]));
        } else {
            retval.push_back(src[endpoints[endpoint_index/2].idx]);
        }
        if (endpoint_index & 1)
            retval.back().reverse();
        endpoints.erase(endpoints.begin() + endpoint_index/2);
        start_near = retval.back().last_point();
    }
    return retval;
}

Polylines
_clipper_pl(ClipperLib::ClipType clipType, const Polygons &subject, 
    const Polygons &clip, bool safety_offset_)
{
    // transform input polygons into polylines
    Polylines polylines;
    polylines.reserve(subject.size());
    for (Polygons::const_iterator polygon = subject.begin(); polygon != subject.end(); ++polygon)
        polylines.push_back(*polygon);  // implicit call to split_at_first_point()
    
    // perform clipping
    Polylines retval = _clipper_pl(clipType, polylines, clip, safety_offset_);
    
    /* If the split_at_first_point() call above happens to split the polygon inside the clipping area
       we would get two consecutive polylines instead of a single one, so we go through them in order
       to recombine continuous polylines. */
    for (size_t i = 0; i < retval.size(); ++i) {
        for (size_t j = i+1; j < retval.size(); ++j) {
            if (retval[i].points.back().coincides_with(retval[j].points.front())) {
                /* If last point of i coincides with first point of j,
                   append points of j to i and delete j */
                retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.front().coincides_with(retval[j].points.back())) {
                /* If first point of i coincides with last point of j,
                   prepend points of j to i and delete j */
                retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.front().coincides_with(retval[j].points.front())) {
                /* Since Clipper does not preserve orientation of polylines, 
                   also check the case when first point of i coincides with first point of j. */
                retval[j].reverse();
                retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.back().coincides_with(retval[j].points.back())) {
                /* Since Clipper does not preserve orientation of polylines, 
                   also check the case when last point of i coincides with last point of j. */
                retval[j].reverse();
                retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
                retval.erase(retval.begin() + j);
                --j;
            }
        }
    }
    return retval;
}

Lines
_clipper_ln(ClipperLib::ClipType clipType, const Lines &subject, const Polygons &clip,
    bool safety_offset_)
{
    // convert Lines to Polylines
    Polylines polylines;
    polylines.reserve(subject.size());
    for (Lines::const_iterator line = subject.begin(); line != subject.end(); ++line)
        polylines.push_back(*line);
    
    // perform operation
    polylines = _clipper_pl(clipType, polylines, clip, safety_offset_);
    
    // convert Polylines to Lines
    Lines retval;
    for (Polylines::const_iterator polyline = polylines.begin(); polyline != polylines.end(); ++polyline)
        retval.push_back(*polyline);
    return retval;
}

void create_polylines (Polylines& polylines)
{
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,1,1));
    polyline.push_back(Point(2,1,1));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,1,1));
    polyline.push_back(Point(2,2,1));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,2,1));
    polyline.push_back(Point(1,2,1));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,2,1));
    polyline.push_back(Point(1,1,1));
    polylines.push_back(polyline);
  }
//----------
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,1,2));
    polyline.push_back(Point(2,1,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,1,2));
    polyline.push_back(Point(2,2,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,2,2));
    polyline.push_back(Point(1,2,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,2,2));
    polyline.push_back(Point(1,1,2));
    polylines.push_back(polyline);
  }
  //----------
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,1,1));
    polyline.push_back(Point(1,1,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,1,1));
    polyline.push_back(Point(2,1,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(2,2,1));
    polyline.push_back(Point(2,2,2));
    polylines.push_back(polyline);
  }
  {
    Polyline_3 polyline;
    polyline.push_back(Point(1,2,1));
    polyline.push_back(Point(1,2,2));
    polylines.push_back(polyline);
  }
}

Polyline::operator Polylines() const
{
    Polylines polylines;
    polylines.push_back(*this);
    return polylines;
}