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mapnik/include/mapnik/geom_util.hpp

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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2017 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_GEOM_UTIL_HPP
#define MAPNIK_GEOM_UTIL_HPP
// mapnik
#include <mapnik/geometry/box2d.hpp>
#include <mapnik/coord.hpp>
#include <mapnik/vertex.hpp>
#include <mapnik/geometry/geometry_types.hpp>
#include <mapnik/geometry/point.hpp>
// stl
#include <cmath>
#include <vector>
#include <algorithm>
// boost
#pragma GCC diagnostic push
#include <mapnik/warning_ignore.hpp>
#include <boost/optional.hpp>
#pragma GCC diagnostic pop
namespace mapnik
{
template <typename T>
bool clip_test(T p,T q,double& tmin,double& tmax)
{
double r = 0;
bool result=true;
if (p<0.0)
{
r=q/p;
if (r>tmax) result=false;
else if (r>tmin) tmin=r;
}
else if (p>0.0)
{
r=q/p;
if (r<tmin) result=false;
else if (r<tmax) tmax=r;
} else if (q<0.0) result=false;
return result;
}
template <typename T,typename Image>
bool clip_line(T& x0,T& y0,T& x1,T& y1,box2d<T> const& box)
{
double tmin=0.0;
double tmax=1.0;
double dx=x1-x0;
if (clip_test<double>(-dx,x0,tmin,tmax))
{
if (clip_test<double>(dx,box.width()-x0,tmin,tmax))
{
double dy=y1-y0;
if (clip_test<double>(-dy,y0,tmin,tmax))
{
if (clip_test<double>(dy,box.height()-y0,tmin,tmax))
{
if (tmax<1.0)
{
x1=static_cast<T>(x0+tmax*dx);
y1=static_cast<T>(y0+tmax*dy);
}
if (tmin>0.0)
{
x0+=static_cast<T>(tmin*dx);
y0+=static_cast<T>(tmin*dy);
}
return true;
}
}
}
}
return false;
}
template <typename Iter>
inline bool point_inside_path(double x,double y,Iter start,Iter end)
{
bool inside=false;
double x0=std::get<0>(*start);
double y0=std::get<1>(*start);
double x1 = 0;
double y1 = 0;
while (++start!=end)
{
if ( std::get<2>(*start) == SEG_MOVETO)
{
x0 = std::get<0>(*start);
y0 = std::get<1>(*start);
continue;
}
x1=std::get<0>(*start);
y1=std::get<1>(*start);
if ((((y1 <= y) && (y < y0)) ||
((y0 <= y) && (y < y1))) &&
( x < (x0 - x1) * (y - y1)/ (y0 - y1) + x1))
inside=!inside;
x0=x1;
y0=y1;
}
return inside;
}
inline bool point_in_circle(double x,double y,double cx,double cy,double r)
{
double dx = x - cx;
double dy = y - cy;
double d2 = dx * dx + dy * dy;
return (d2 <= r * r);
}
template <typename T>
inline T sqr(T x)
{
return x * x;
}
inline double distance2(double x0, double y0, double x1, double y1)
{
double dx = x1 - x0;
double dy = y1 - y0;
return sqr(dx) + sqr(dy);
}
inline double distance(double x0, double y0, double x1, double y1)
{
return std::sqrt(distance2(x0, y0, x1, y1));
}
inline double point_to_segment_distance(double x, double y,
double ax, double ay,
double bx, double by)
{
double len2 = distance2(ax, ay, bx, by);
if (len2 < 1e-14)
{
return distance(x, y, ax, ay);
}
double r = ((x - ax) * (bx - ax) + (y - ay) * (by - ay)) / len2;
if (r < 0)
{
return distance(x, y, ax, ay);
}
else if (r > 1)
{
return distance(x, y, bx, by);
}
double s = ((ay - y) * (bx - ax) - (ax - x) * (by - ay)) / len2;
return std::fabs(s) * std::sqrt(len2);
}
template <typename Iter>
inline bool point_on_path(double x, double y, Iter start, Iter end, double tol)
{
double x0 = std::get<0>(*start);
double y0 = std::get<1>(*start);
double x1 = 0;
double y1 = 0;
while (++start != end)
{
if (std::get<2>(*start) == SEG_MOVETO)
{
x0 = std::get<0>(*start);
y0 = std::get<1>(*start);
continue;
}
x1 = std::get<0>(*start);
y1 = std::get<1>(*start);
double distance = point_to_segment_distance(x, y, x0, y0, x1, y1);
if (distance < tol)
return true;
x0 = x1;
y0 = y1;
}
return false;
}
// filters
template <typename T>
struct bounding_box_filter
{
using value_type = T;
box2d<value_type> box_;
explicit bounding_box_filter(box2d<value_type> const& box)
: box_(box) {}
bool pass(box2d<value_type> const& extent) const
{
return extent.intersects(box_);
}
};
using filter_in_box = bounding_box_filter<double>;
template <typename T>
struct at_point_filter
{
using value_type = T;
box2d<value_type> box_;
explicit at_point_filter(coord<value_type, 2> const& pt, double tol = 0)
: box_(pt, pt)
{
box_.pad(tol);
}
bool pass(box2d<value_type> const& extent) const
{
return extent.intersects(box_);
}
};
using filter_at_point = at_point_filter<double>;
////////////////////////////////////////////////////////////////////////////
template <typename PathType>
double path_length(PathType & path)
{
double x0 = 0;
double y0 = 0;
double x1 = 0;
double y1 = 0;
path.rewind(0);
unsigned command = path.vertex(&x0,&y0);
if (command == SEG_END) return 0;
double length = 0;
while (SEG_END != (command = path.vertex(&x1, &y1)))
{
if (command == SEG_CLOSE) continue;
length += distance(x0,y0,x1,y1);
x0 = x1;
y0 = y1;
}
return length;
}
template <typename PathType>
bool hit_test_first(PathType & path, double x, double y)
{
bool inside=false;
double x0 = 0;
double y0 = 0;
double x1 = 0;
double y1 = 0;
path.rewind(0);
unsigned command = path.vertex(&x0, &y0);
if (command == SEG_END)
{
return false;
}
unsigned count = 0;
while (SEG_END != (command = path.vertex(&x1, &y1)))
{
if (command == SEG_CLOSE)
{
break;
}
++count;
if (command == SEG_MOVETO)
{
x0 = x1;
y0 = y1;
continue;
}
if ((((y1 <= y) && (y < y0)) ||
((y0 <= y) && (y < y1))) &&
(x < (x0 - x1) * (y - y1)/ (y0 - y1) + x1))
inside=!inside;
x0 = x1;
y0 = y1;
}
return inside;
}
namespace label {
template <typename PathType>
bool middle_point(PathType & path, double & x, double & y, boost::optional<double&> angle = boost::none)
{
double x0 = 0;
double y0 = 0;
double x1 = 0;
double y1 = 0;
double mid_length = 0.5 * path_length(path);
path.rewind(0);
unsigned command = path.vertex(&x0,&y0);
if (command == SEG_END) return false;
if (std::abs(mid_length) < std::numeric_limits<double>::epsilon())
{
x = x0;
y = y0;
return true;
}
double dist = 0.0;
while (SEG_END != (command = path.vertex(&x1, &y1)))
{
if (command == SEG_CLOSE) continue;
double seg_length = distance(x0, y0, x1, y1);
if ( dist + seg_length >= mid_length)
{
double r = (mid_length - dist)/seg_length;
x = x0 + (x1 - x0) * r;
y = y0 + (y1 - y0) * r;
if (angle)
{
*angle = atan2(y1 - y0, x1 - x0);
}
break;
}
dist += seg_length;
x0 = x1;
y0 = y1;
}
return true;
}
template <typename PathType>
bool centroid(PathType & path, double & x, double & y)
{
geometry::point<double> p0, p1, move_to, start;
path.rewind(0);
unsigned command = path.vertex(&p0.x, &p0.y);
if (command == SEG_END) return false;
start = move_to = p0;
double atmp = 0.0;
double xtmp = 0.0;
double ytmp = 0.0;
unsigned count = 1;
while (SEG_END != (command = path.vertex(&p1.x, &p1.y)))
{
switch (command)
{
case SEG_MOVETO:
move_to = p1;
break;
case SEG_CLOSE:
p1 = move_to;
case SEG_LINETO:
double dx0 = p0.x - start.x;
double dy0 = p0.y - start.y;
double dx1 = p1.x - start.x;
double dy1 = p1.y - start.y;
double ai = dx0 * dy1 - dx1 * dy0;
atmp += ai;
xtmp += (dx1 + dx0) * ai;
ytmp += (dy1 + dy0) * ai;
break;
}
p0 = p1;
++count;
}
if (count <= 2)
{
x = (start.x + p0.x) * 0.5;
y = (start.y + p0.y) * 0.5;
return true;
}
if (atmp != 0)
{
x = (xtmp / (3 * atmp)) + start.x;
y = (ytmp / (3 * atmp)) + start.y;
}
else
{
x = p0.x;
y = p0.y;
}
return true;
}
// Compute centroid over a set of paths
#if 0
template <typename Iter>
bool centroid_geoms(Iter start, Iter end, double & x, double & y)
{
double x0 = 0.0;
double y0 = 0.0;
double x1 = 0.0;
double y1 = 0.0;
double start_x = x0;
double start_y = y0;
double atmp = 0.0;
double xtmp = 0.0;
double ytmp = 0.0;
unsigned count = 0;
while (start != end)
{
typename Iter::value_type const& geom = *start++;
vertex_adapter path(geom);
path.rewind(0);
unsigned command = path.vertex(&x0, &y0);
if (command == SEG_END) continue;
if ( ! count++ ) {
start_x = x0;
start_y = y0;
}
while (SEG_END != (command = path.vertex(&x1, &y1)))
{
if (command == SEG_CLOSE) continue;
double dx0 = x0 - start_x;
double dy0 = y0 - start_y;
double dx1 = x1 - start_x;
double dy1 = y1 - start_y;
double ai = dx0 * dy1 - dx1 * dy0;
atmp += ai;
xtmp += (dx1 + dx0) * ai;
ytmp += (dy1 + dy0) * ai;
x0 = x1;
y0 = y1;
++count;
}
}
if (count == 0) return false;
if (count <= 2) {
x = (start_x + x0) * 0.5;
y = (start_y + y0) * 0.5;
return true;
}
if (atmp != 0)
{
x = (xtmp/(3*atmp)) + start_x;
y = (ytmp/(3*atmp)) + start_y;
}
else
{
x = x0;
y = y0;
}
return true;
}
#endif
template <typename PathType>
bool hit_test(PathType & path, double x, double y, double tol)
{
bool inside=false;
double x0 = 0;
double y0 = 0;
double x1 = 0;
double y1 = 0;
double start_x = 0;
double start_y = 0;
path.rewind(0);
unsigned command = path.vertex(&x0, &y0);
if (command == SEG_END)
{
return false;
}
unsigned count = 0;
mapnik::geometry::geometry_types geom_type = static_cast<mapnik::geometry::geometry_types>(path.type());
while (SEG_END != (command = path.vertex(&x1, &y1)))
{
++count;
if (command == SEG_MOVETO)
{
x0 = x1;
y0 = y1;
start_x = x0;
start_y = y0;
continue;
}
else if (command == SEG_CLOSE)
{
x1 = start_x;
y1 = start_y;
}
switch(geom_type)
{
case mapnik::geometry::geometry_types::Polygon:
{
if ((((y1 <= y) && (y < y0)) ||
((y0 <= y) && (y < y1))) &&
(x < (x0 - x1) * (y - y1)/ (y0 - y1) + x1))
inside=!inside;
break;
}
case mapnik::geometry::geometry_types::LineString:
{
double distance = point_to_segment_distance(x,y,x0,y0,x1,y1);
if (distance < tol)
return true;
break;
}
default:
break;
}
x0 = x1;
y0 = y1;
}
// TODO - handle multi-point?
if (count == 0) // one vertex
{
return distance(x, y, x0, y0) <= tol;
}
return inside;
}
}}
#endif // MAPNIK_GEOM_UTIL_HPP
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