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mapnik/plugins/input/tiles/vector_tiles_featureset.cpp

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4.3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2025 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/well_known_srs.hpp>
#include "tiles_source.hpp"
#include "vector_tiles_featureset.hpp"
// boost
#include <boost/format.hpp>
vector_tiles_featureset::vector_tiles_featureset(std::shared_ptr<mapnik::tiles_source> source_ptr,
mapnik::context_ptr const& ctx,
const int zoom,
mapnik::box2d<double> const& extent,
std::string const& layer,
std::unordered_map<std::string, std::string>& vector_tile_cache,
std::size_t datasource_hash)
: source_ptr_(source_ptr)
, context_(ctx)
, zoom_(zoom)
, extent_(extent)
, layer_(layer)
, vector_tile_(nullptr)
, vector_tile_cache_(vector_tile_cache)
, datasource_hash_(datasource_hash)
{
extent_.set_minx(extent_.minx() + 1e-6);
extent_.set_maxx(extent_.maxx() - 1e-6);
extent_.set_miny(extent_.miny() + 1e-6);
extent_.set_maxy(extent_.maxy() - 1e-6);
int tile_count = 1 << zoom;
xmin_ =
static_cast<int>((extent_.minx() + mapnik::EARTH_CIRCUMFERENCE / 2) * (tile_count / mapnik::EARTH_CIRCUMFERENCE));
xmax_ =
static_cast<int>((extent_.maxx() + mapnik::EARTH_CIRCUMFERENCE / 2) * (tile_count / mapnik::EARTH_CIRCUMFERENCE));
ymin_ = static_cast<int>(((mapnik::EARTH_CIRCUMFERENCE / 2) - extent_.maxy()) *
(tile_count / mapnik::EARTH_CIRCUMFERENCE));
ymax_ = static_cast<int>(((mapnik::EARTH_CIRCUMFERENCE / 2) - extent_.miny()) *
(tile_count / mapnik::EARTH_CIRCUMFERENCE));
x_ = xmin_;
y_ = ymin_;
open_tile();
}
vector_tiles_featureset::~vector_tiles_featureset() {}
bool vector_tiles_featureset::valid() const
{
return vector_tile_.get() != nullptr;
}
mapnik::feature_ptr vector_tiles_featureset::next_feature()
{
mapnik::feature_ptr f = mapnik::feature_ptr();
if (valid())
{
f = vector_tile_->next();
}
return f;
}
mapnik::feature_ptr vector_tiles_featureset::next()
{
// If current tile is processed completely, go forward to the next tile.
// else step forward to the next feature
mapnik::feature_ptr f = next_feature();
if (f)
{
return f;
}
while (next_tile() && open_tile() && valid())
{
f = next_feature();
if (f)
{
return f;
}
}
return mapnik::feature_ptr();
}
bool vector_tiles_featureset::next_tile()
{
++x_;
if (x_ <= xmax_)
{
return true;
}
x_ = xmin_;
++y_;
return y_ <= ymax_;
}
bool vector_tiles_featureset::open_tile()
{
auto datasource_key = (boost::format("%1%-%2%-%3%-%4%") % datasource_hash_ % zoom_ % x_ % y_).str();
auto itr = vector_tile_cache_.find(datasource_key);
if (itr == vector_tile_cache_.end())
{
auto decompressed = source_ptr_->get_tile(zoom_, x_, y_);
vector_tile_cache_.emplace(datasource_key, decompressed);
vector_tile_.reset(new mvt_io(std::move(decompressed), context_, x_, y_, zoom_, layer_));
}
else
{
std::string buffer = itr->second;
vector_tile_.reset(new mvt_io(std::move(buffer), context_, x_, y_, zoom_, layer_));
}
return true;
}