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/* This file is part of the libdepixelize project
Copyright (C) 2013 Vinícius dos Santos Oliveira <vini.ipsmaker@gmail.com>
GNU Lesser General Public License Usage
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.
You should have received a copy of the GNU Lesser General Public License
along with this library. If not, see <http://www.gnu.org/licenses/>.
GNU General Public License Usage
Alternatively, this library may be used under the terms of the GNU General
Public License as published by the Free Software Foundation, either version
2 of the License, or (at your option) any later version.
You should have received a copy of the GNU General Public License along with
this library. If not, see <http://www.gnu.org/licenses/>.
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.
*/
#ifndef LIBDEPIXELIZE_TRACER_HOMOGENEOUSSPLINES_H
#define LIBDEPIXELIZE_TRACER_HOMOGENEOUSSPLINES_H
#include "simplifiedvoronoi.h"
#include "point.h"
#include <algorithm>
#include <utility>
namespace Tracer {
template<typename T>
class HomogeneousSplines
{
public:
struct Polygon
{
typedef std::vector< Point<T> > Points;
typedef typename Points::iterator points_iter;
typedef typename Points::const_iterator const_points_iter;
typedef typename std::vector<Points>::iterator holes_iter;
typedef typename std::vector<Points>::const_iterator const_holes_iter;
Polygon() {}
Polygon(const guint8 (&rgba)[4])
{
for ( int i = 0 ; i != 4 ; ++i )
this->rgba[i] = rgba[i];
}
std::vector< Point<T> > vertices;
/**
* It may be benefited from C++11 move references.
*/
std::vector< std::vector< Point<T> > > holes;
guint8 rgba[4];
};
typedef typename std::vector<Polygon>::iterator iterator;
typedef typename std::vector<Polygon>::const_iterator const_iterator;
typedef typename std::vector<Polygon>::size_type size_type;
template<bool adjust_splines>
HomogeneousSplines(const SimplifiedVoronoi<T, adjust_splines> &voronoi);
// Iterators
iterator begin()
{
return _polygons.begin();
}
const_iterator begin() const
{
return _polygons.begin();
}
iterator end()
{
return _polygons.end();
}
const_iterator end() const
{
return _polygons.end();
}
size_type size() const
{
return _polygons.size();
}
int width() const
{
return _width;
}
int height() const
{
return _height;
}
private:
typedef std::vector< Point<T> > Points;
typedef typename Points::iterator points_iter;
typedef typename Points::const_iterator points_citer;
typedef typename Points::reverse_iterator points_riter;
typedef typename Points::const_reverse_iterator points_criter;
typedef std::pair<points_iter, points_iter> points_range;
typedef std::pair<points_citer, points_citer> points_crange;
struct CommonEdge
{
bool ok; //< share an edge
Points *dst;
const Points *src;
// the interval is closed on both ends
// different from [begin, end) STL style
points_iter dst_begin, dst_end;
points_citer src_begin, src_end;
};
struct SelfCommonEdge
{
bool ok; //< share an edge
// Greater range. The one that should be erased from the vector.
points_riter grt_begin, grt_end;
// Smaller range. The one that should be used to create a new vector.
points_riter sml_begin, sml_end;
};
/**
* Return ok == true if they share an edge (more than one point).
*/
CommonEdge _common_edge(Points &dst, const Points &src);
/**
* Return ok == true if they share an edge (more than one point).
*
* - [dst_begin, dst_end) will contain the hole polygon
* - [src_begin, src_end) will contain the range to be erased
*
* It's required to do the search in backward order.
*/
SelfCommonEdge _common_edge(Points &points, points_riter it);
/*!
* Add polygon represented by \p common_edge.src to \p common_edge.dst.
*/
void _polygon_union(CommonEdge common_edge);
/**
* Weird recursive function created to solve the complex problem to fill
* polygons holes without the need to store temporaries on the heap nor
* changing requirements to some data type that don't invalidate iterators
* that point before the current element (maybe I'll write some poetry about
* the problem someday).
*/
void _fill_holes(std::vector<Points> &holes, points_iter region_begin,
points_iter region_end);
std::vector<Polygon> _polygons;
int _width;
int _height;
};
template<class T>
template<bool adjust_splines>
HomogeneousSplines<T>::HomogeneousSplines(const SimplifiedVoronoi<T,
adjust_splines> &voronoi) :
_width(voronoi.width()),
_height(voronoi.height())
{
//if (!voronoi.size())
// return;
using colorspace::same_color;
typedef typename SimplifiedVoronoi<T, adjust_splines>::const_iterator
voronoi_citer;
// Identify visible edges (group polygons with the same color)
for ( voronoi_citer cell_it = voronoi.begin(), cell_end = voronoi.end()
; cell_it != cell_end ; ++cell_it ) {
bool found = false;
for ( iterator polygon_it = _polygons.begin(),
polygon_end = _polygons.end()
; polygon_it != polygon_end ; ++polygon_it ) {
if ( same_color(polygon_it->rgba, cell_it->rgba) ) {
CommonEdge common_edge = _common_edge(polygon_it->vertices,
cell_it->vertices);
if ( common_edge.ok ) {
_polygon_union(common_edge);
found = true;
for ( iterator polygon2_it = polygon_it + 1
; polygon2_it != polygon_end ; ++polygon2_it ) {
if ( same_color(polygon_it->rgba, polygon2_it->rgba) ) {
CommonEdge common_edge2
= _common_edge(polygon_it->vertices,
polygon2_it->vertices);
if ( common_edge2.ok ) {
_polygon_union(common_edge2);
_polygons.erase(polygon2_it);
break;
}
}
}
break;
}
}
}
if ( !found ) {
Polygon polygon(cell_it->rgba);
polygon.vertices = cell_it->vertices;
_polygons.insert(_polygons.end(), polygon);
}
}
// Find polygons with holes and fix them
// This iteration runs such complex time-consuming algorithm, but each
// polygon has an independent result. They wouldn't even need to share/sync
// results and the only waste would be a join at the end of the for.
for ( typename std::vector<Polygon>::iterator it = _polygons.begin(),
end = _polygons.end() ; it != end ; ++it ) {
SelfCommonEdge ce = _common_edge(it->vertices, it->vertices.rbegin());
while ( ce.ok ) {
_fill_holes(it->holes, ce.sml_end.base(), ce.sml_begin.base());
it->vertices.erase(ce.grt_end.base() + 1, ce.grt_begin.base());
ce = _common_edge(it->vertices, ce.grt_end);
}
}
}
// it can infinite loop if points of both entities are equal,
// but this shouldn't happen if user has only access to Kopf2011 interface
template<class T>
typename HomogeneousSplines<T>::CommonEdge
HomogeneousSplines<T>::_common_edge(Points &dst, const Points &src)
{
// It's an edge, then the points are closer together. After we find the
// first point, there is no need for check against all points of the src
// a second time
const points_iter dst_begin = dst.begin();
const points_iter dst_end = dst.end();
const points_citer src_begin = src.begin();
const points_citer src_end = src.end();
for ( points_iter it = dst_begin ; it != dst_end ; ++it ) {
points_citer src_it = std::find(src_begin, src_end, *it);
if ( src_it == src_end )
continue;
points_iter dst_common_edge_begin = it;
points_citer src_common_edge_end = src_it;
// iterate until find the beginning of the common edge range
while ( *dst_common_edge_begin == *src_common_edge_end ) {
if ( dst_common_edge_begin == dst_begin )
dst_common_edge_begin = dst_end - 1;
else
--dst_common_edge_begin;
++src_common_edge_end;
if ( src_common_edge_end == src_end )
src_common_edge_end = src_begin;
}
// fix {dst_begin, src_end} range
++dst_common_edge_begin;
if ( dst_common_edge_begin == dst_end )
dst_common_edge_begin = dst_begin;
if ( src_common_edge_end == src_begin )
src_common_edge_end = src_end - 1;
else
--src_common_edge_end;
points_iter dst_common_edge_end = it;
points_citer src_common_edge_begin = src_it;
// find the end of the common edge range
while ( *dst_common_edge_end == *src_common_edge_begin ) {
++dst_common_edge_end;
if ( dst_common_edge_end == dst_end )
dst_common_edge_end = dst_begin;
if ( src_common_edge_begin == src_begin )
src_common_edge_begin = src_end - 1;
else
--src_common_edge_begin;
}
// fix {dst_end, src_begin} range
if ( dst_common_edge_end == dst_begin )
dst_common_edge_end = dst_end - 1;
else
--dst_common_edge_end;
++src_common_edge_begin;
if ( src_common_edge_begin == src_end )
src_common_edge_begin = src_begin;
CommonEdge ret;
// if only one point in common
if ( dst_common_edge_begin == dst_common_edge_end )
continue;
ret.ok = true;
ret.dst = &dst;
ret.dst_begin = dst_common_edge_begin;
ret.dst_end = dst_common_edge_end;
ret.src = &src;
ret.src_begin = src_common_edge_begin;
ret.src_end = src_common_edge_end;
return ret;
}
CommonEdge ret;
ret.ok = false;
return ret;
}
template<class T>
typename HomogeneousSplines<T>::SelfCommonEdge
HomogeneousSplines<T>::_common_edge(Points &points, points_riter it)
{
SelfCommonEdge ret;
ret.grt_end = points.rend();
for ( ; it != ret.grt_end ; ++it ) {
ret.sml_end = std::find(it + 1, ret.grt_end, *it);
if ( ret.sml_end == ret.grt_end )
continue;
ret.grt_begin = it;
ret.grt_end = ret.sml_end + 1;
ret.sml_begin = it;
while ( *ret.sml_begin == *ret.sml_end ) {
++ret.sml_begin;
--ret.sml_end;
}
--ret.sml_begin;
++ret.sml_end;
++ret.sml_end;
ret.ok = true;
return ret;
}
ret.ok = false;
return ret;
}
template<class T>
void HomogeneousSplines<T>::_polygon_union(CommonEdge common_edge)
{
Points &dst = *common_edge.dst;
const Points &src = *common_edge.src;
// the rotated cell must be inserted before (dst.begin() + index)
typename Points::difference_type index;
// first, we remove the common edge in dst
if ( common_edge.dst_begin < common_edge.dst_end ) {
// common edge is in the middle of dst
index = dst.erase(common_edge.dst_begin,
common_edge.dst_end + 1) - dst.begin();
} else {
// common edge cross the end of dst
dst.erase(common_edge.dst_begin, dst.end());
dst.erase(dst.begin(), common_edge.dst_end);
index = dst.end() - dst.begin();
}
// second, we copy src points to polygon
if ( common_edge.src_begin < common_edge.src_end ) {
// common edge is in the middle of src
const typename Points::difference_type nfirstinserted
= src.end() - common_edge.src_end;
const typename Points::difference_type nsecondinserted
= 1 + (common_edge.src_begin - src.begin());
dst.reserve(dst.size() + nfirstinserted + nsecondinserted);
dst.insert(dst.begin() + index, common_edge.src_end, src.end());
dst.insert(dst.begin() + index + nfirstinserted,
src.begin(), common_edge.src_begin + 1);
} else {
// common edge cross the end of src
dst.reserve(dst.size() + 1
+ (common_edge.src_begin - common_edge.src_end));
dst.insert(dst.begin() + index,
common_edge.src_end, common_edge.src_begin + 1);
}
}
// The following piece of code is so evil that you could end up invoking an
// ancient beast if you proceed to read it, but I'll be able to explain it in
// the form of some video (text is not so representative as an image).
template<class T>
void HomogeneousSplines<T>::_fill_holes(std::vector<Points> &holes,
points_iter region_begin,
points_iter region_end)
{
// the exact location might not always be back and iterators will be
// invalidated after some insertions, then the index is required
const typename std::vector<Points>::size_type hole_index = holes.size();
holes.resize(hole_index + 1);
for ( points_iter it = region_begin + 1 ; it != region_end ; ++it ) {
points_iter res = std::find(it + 1, region_end, *it);
if ( res == region_end )
continue;
holes[hole_index].insert(holes[hole_index].end(), region_begin,
it);
region_begin = res;
do {
++it;
--res;
} while ( *it == *res );
_fill_holes(holes, it - 1, res + 2);
it = region_begin;
}
holes[hole_index].insert(holes[hole_index].end(), region_begin,
region_end - 1);
}
} // namespace Tracer
#endif // LIBDEPIXELIZE_TRACER_HOMOGENEOUSSPLINES_H
/*
Local Variables:
mode:c++
c-file-style:"stroustrup"
c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
indent-tabs-mode:nil
fill-column:99
End:
*/
// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :
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