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[centroid] Disable translation for non-areal Geometries.

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This commit is contained in:
Adam Wulkiewicz
2014-10-11 11:57:49 +02:00
parent 5e3656a09a
commit 95b3fb45d3
1 changed files with 50 additions and 31 deletions
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81
include/boost/geometry/algorithms/centroid.hpp
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@@ -202,34 +202,42 @@ inline bool range_ok(Range const& range, Point& centroid)
// cartesian. But if it was needed then one should translate using
// CS-specific technique, e.g. in spherical/geographic a translation
// vector should contain coordinates being multiplies of 2PI or 360 deg.
template <typename Pt, typename CSTag = typename cs_tag<Pt>::type>
template <typename Geometry,
typename CastedTag = typename tag_cast
<
typename tag<Geometry>::type,
areal_tag
>::type,
typename CSTag = typename cs_tag<Geometry>::type>
struct translating_transformer
{
typedef boost::reference_wrapper<Pt const> result_type;
typedef typename geometry::point_type<Geometry>::type point_type;
typedef boost::reference_wrapper<point_type const> result_type;
translating_transformer(Pt const&) {}
translating_transformer(point_type const&) {}
result_type apply(Pt const& pt) const
result_type apply(point_type const& pt) const
{
return result_type(pt);
}
template <typename ResPt>
void apply_reverse(ResPt & res_pt) const {}
void apply_reverse(ResPt &) const {}
};
template <typename Pt>
struct translating_transformer<Pt, cartesian_tag>
template <typename Geometry>
struct translating_transformer<Geometry, areal_tag, cartesian_tag>
{
typedef Pt result_type;
typedef typename geometry::point_type<Geometry>::type point_type;
typedef point_type result_type;
translating_transformer(Pt const& origin)
translating_transformer(point_type const& origin)
: m_origin(origin)
{}
result_type apply(Pt const& pt) const
result_type apply(point_type const& pt) const
{
Pt res = pt;
point_type res = pt;
geometry::subtract_point(res, m_origin);
return res;
}
@@ -240,11 +248,36 @@ struct translating_transformer<Pt, cartesian_tag>
geometry::add_point(res_pt, m_origin);
}
Pt const& m_origin;
point_type const& m_origin;
};
template <typename Geometry>
inline void assign_origin(Geometry const& geom,
typename geometry::point_type<Geometry>::type & origin)
{
static const bool is_areal
= boost::is_same
<
typename tag_cast<typename tag<Geometry>::type, areal_tag>::type,
areal_tag
>::value;
if ( is_areal )
{
geometry::point_iterator<Geometry const>
pt_it = geometry::points_begin(geom);
if ( pt_it != geometry::points_end(geom) )
{
origin = *pt_it;
return;
}
}
geometry::assign_zero(origin);
}
/*!
\brief Calculate the centroid of a ring.
\brief Calculate the centroid of a Ring or a Linestring.
*/
template <closure_selector Closure>
struct centroid_range_state
@@ -291,9 +324,7 @@ struct centroid_range
if (range_ok(range, centroid))
{
// prepare translation transformer
typedef typename geometry::point_type<Range>::type point_type;
translating_transformer<point_type>
transformer(*boost::begin(range));
translating_transformer<Range> transformer(*boost::begin(range));
typename Strategy::state_type state;
centroid_range_state<Closure>::apply(range, transformer,
@@ -345,8 +376,7 @@ struct centroid_polygon
if (range_ok(exterior_ring(poly), centroid))
{
// prepare translation transformer
typedef typename geometry::point_type<Polygon>::type point_type;
translating_transformer<point_type>
translating_transformer<Polygon>
transformer(*boost::begin(exterior_ring(poly)));
typename Strategy::state_type state;
@@ -406,19 +436,8 @@ struct centroid_multi
// prepare translation transformer
typedef typename geometry::point_type<Multi>::type point_type;
point_type origin;
{
geometry::point_iterator<Multi const>
pt_it = geometry::points_begin(multi);
if ( pt_it != geometry::points_end(multi) )
{
origin = *pt_it;
}
else
{
geometry::assign_zero(origin);
}
}
translating_transformer<point_type> transformer(origin);
assign_origin(multi, origin);
translating_transformer<Multi> transformer(origin);
typename Strategy::state_type state;