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Added the rounding_cast utility, and added a scale_rounding_strategy to support this new casting type. Added tests for it

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This commit is contained in:
Blake Thompson 2015-05-12 14:36:29 -05:00
parent 1dddfd17ef
commit 39428585f0
3 changed files with 128 additions and 2 deletions
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52
include/mapnik/geometry_strategy.hpp
View file

@ -24,6 +24,7 @@
#define MAPNIK_GEOMETRY_STRATEGY_HPP
#include <mapnik/geometry_adapters.hpp>
#include <mapnik/util/rounding_cast.hpp>
namespace mapnik {
namespace geometry {
@ -192,6 +193,57 @@ private:
double offset_;
};
struct scale_rounding_strategy
{
scale_rounding_strategy(double scale, double offset = 0)
: scale_(scale), offset_(offset) {}
template <typename P1, typename P2>
inline bool apply(P1 const & p1, P2 & p2) const
{
using p2_type = typename boost::geometry::coordinate_type<P2>::type;
double x = (boost::geometry::get<0>(p1) * scale_) + offset_;
double y = (boost::geometry::get<1>(p1) * scale_) + offset_;
try {
boost::geometry::set<0>(p2, util::rounding_cast<p2_type>(x));
}
catch(boost::numeric::negative_overflow&)
{
boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::min());
}
catch(boost::numeric::positive_overflow&)
{
boost::geometry::set<0>(p2, std::numeric_limits<p2_type>::max());
}
try {
boost::geometry::set<1>(p2, util::rounding_cast<p2_type>(y));
}
catch(boost::numeric::negative_overflow&)
{
boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::min());
}
catch(boost::numeric::positive_overflow&)
{
boost::geometry::set<1>(p2, std::numeric_limits<p2_type>::max());
}
return true;
}
template <typename P1, typename P2>
inline P2 execute(P1 const& p1, bool & status) const
{
P2 p2;
status = apply(p1, p2);
return p2;
}
private:
double scale_;
double offset_;
};
} // end geometry ns
} // end mapnik ns

48
include/mapnik/util/rounding_cast.hpp Normal file
View file

@ -0,0 +1,48 @@
/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2015 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
*
*****************************************************************************/
#ifndef MAPNIK_UTIL_ROUNDING_CAST_HPP
#define MAPNIK_UTIL_ROUNDING_CAST_HPP
#include <boost/numeric/conversion/converter.hpp>
namespace mapnik {
namespace util {
template<typename Target, typename Source>
inline
Target rounding_cast ( Source arg )
{
typedef boost::numeric::conversion_traits<Target,Source> Traits ;
typedef
boost::numeric::converter<Target,Source,Traits,boost::numeric::def_overflow_handler,boost::numeric::RoundEven<Source>
> Converter ;
return Converter::convert(arg);
}
} // end util ns
} // end mapnik ns
#endif //MAPNIK_UTIL_ROUNDING_CAST_HPP

30
test/unit/geometry/geometry_strategy_test.cpp
View file

@ -88,8 +88,8 @@ SECTION("proj and view strategy") {
}
{
// Test with scaling as well. This would be like projection from 4326 to a vector tile.
mapnik::geometry::scale_strategy ss(16, 0.5);
using sg_type = strategy_group<mapnik::proj_strategy, mapnik::view_strategy, mapnik::geometry::scale_strategy >;
mapnik::geometry::scale_rounding_strategy ss(16);
using sg_type = strategy_group<mapnik::proj_strategy, mapnik::view_strategy, mapnik::geometry::scale_rounding_strategy >;
sg_type sg(ps, vs, ss);
geometry<double> p1(std::move(point<double>(-97.553098,35.523105)));
point<std::int64_t> r1(938 , 1615);
@ -112,6 +112,32 @@ SECTION("proj and view strategy") {
//std::cout << p3.x << " , " << p3.y << std::endl;
assert_g_equal(r1, p3);
}
{
// Test with scaling + offset as well. This would be like projection from 4326 to a vector tile.
mapnik::geometry::scale_rounding_strategy ss(16, 20);
using sg_type = strategy_group<mapnik::proj_strategy, mapnik::view_strategy, mapnik::geometry::scale_rounding_strategy >;
sg_type sg(ps, vs, ss);
geometry<double> p1(std::move(point<double>(-97.553098,35.523105)));
point<std::int64_t> r1(958 , 1635);
geometry<std::int64_t> p2 = transform<std::int64_t>(p1, sg);
REQUIRE(p2.is<point<std::int64_t> >());
point<std::int64_t> p3 = mapnik::util::get<point<std::int64_t> >(p2);
//std::cout << p3.x << " , " << p3.y << std::endl;
assert_g_equal(r1, p3);
}
{
// Test the entire scaling plus offset in reverse process in reverse! This would be like converting a vector tile coordinate to 4326.
mapnik::geometry::scale_strategy ss(1.0/16.0, -20.0/16.0);
using sg_type = strategy_group_first<mapnik::geometry::scale_strategy, mapnik::unview_strategy, mapnik::proj_strategy >;
sg_type sg(ss, uvs, ps_rev);
geometry<std::int64_t> p1(std::move(point<std::int64_t>(958 , 1635)));
point<double> r1(-97.5586 , 35.5322);
geometry<double> p2 = transform<double>(p1, sg);
REQUIRE(p2.is<point<double> >());
point<double> p3 = mapnik::util::get<point<double> >(p2);
//std::cout << p3.x << " , " << p3.y << std::endl;
assert_g_equal(r1, p3);
}
}