mapnik/src/grid/grid.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2012 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

// mapnik
#include <mapnik/grid/grid.hpp>

namespace mapnik
{

template <typename T>
const typename hit_grid<T>::value_type hit_grid<T>::base_mask = std::numeric_limits<T>::min();

template <typename T>
hit_grid<T>::hit_grid(int width, int height, std::string const& key, unsigned int resolution)
    : width_(width),
      height_(height),
      key_(key),
      data_(width,height),
      resolution_(resolution),
      id_name_("__id__"),
      painted_(false),
      names_(),
      f_keys_(),
      features_(),
      ctx_(boost::make_shared<mapnik::context_type>())
      {
          f_keys_[base_mask] = "";
          data_.set(base_mask);
      }

template <typename T>
hit_grid<T>::hit_grid(const hit_grid<T>& rhs)
    : width_(rhs.width_),
      height_(rhs.height_),
      key_(rhs.key_),
      data_(rhs.data_),
      resolution_(rhs.resolution_),
      id_name_("__id__"),
      painted_(rhs.painted_),
      names_(rhs.names_),
      f_keys_(rhs.f_keys_),
      features_(rhs.features_),
      ctx_(rhs.ctx_)
      {
          f_keys_[base_mask] = "";
          data_.set(base_mask);
      }

template <typename T>
void hit_grid<T>::add_feature(mapnik::feature_impl & feature)
{
    int feature_id = feature.id();
    // avoid adding duplicate features (e.g. in the case of both a line symbolizer and a polygon symbolizer)
    typename feature_key_type::const_iterator feature_pos = f_keys_.find(feature_id);
    if (feature_pos != f_keys_.end())
    {
        return;
    }

    if (ctx_->size() == 0) {
        mapnik::feature_impl::iterator itr = feature.begin();
        mapnik::feature_impl::iterator end = feature.end();
        for ( ;itr!=end; ++itr)
        {
            ctx_->push(boost::get<0>(*itr));
        }
    }
    // NOTE: currently lookup keys must be strings,
    // but this should be revisited
    lookup_type lookup_value;
    if (key_ == id_name_)
    {
        mapnik::util::to_string(lookup_value,feature_id);
    }
    else
    {
        if (feature.has_key(key_))
        {
            lookup_value = feature.get(key_).to_string();
        }
        else
        {
            MAPNIK_LOG_DEBUG(grid) << "hit_grid: Should not get here: key '" << key_ << "' not found in feature properties";
        }
    }

    if (!lookup_value.empty())
    {
        // TODO - consider shortcutting f_keys if feature_id == lookup_value
        // create a mapping between the pixel id and the feature key
        f_keys_.insert(std::make_pair(feature_id,lookup_value));
        // if extra fields have been supplied, push them into grid memory
        if (!names_.empty())
        {
            // it is ~ 2x faster to copy feature attributes compared
            // to building up a in-memory cache of feature_ptrs
            // https://github.com/mapnik/mapnik/issues/1198
            mapnik::feature_ptr feature2(mapnik::feature_factory::create(ctx_,feature_id));
            feature2->set_data(feature.get_data());
            features_.insert(std::make_pair(lookup_value,feature2));
        }
    }
    else
    {
        MAPNIK_LOG_DEBUG(grid) << "hit_grid: Warning - key '" << key_ << "' was blank for " << feature;
    }
}


template class hit_grid<int>;

}