514 lines
16 KiB
C++
514 lines
16 KiB
C++
/*****************************************************************************
|
|
*
|
|
* This file is part of Mapnik (c++ mapping toolkit)
|
|
*
|
|
* Copyright (C) 2011 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_HEXTREE_HPP
|
|
#define MAPNIK_HEXTREE_HPP
|
|
|
|
// mapnik
|
|
#include <mapnik/global.hpp>
|
|
#include <mapnik/palette.hpp>
|
|
#include <mapnik/noncopyable.hpp>
|
|
|
|
// boost
|
|
#include <boost/version.hpp>
|
|
#if BOOST_VERSION >= 104600
|
|
#include <boost/range/algorithm.hpp>
|
|
#endif
|
|
|
|
|
|
// stl
|
|
#include <vector>
|
|
#include <set>
|
|
#include <algorithm>
|
|
#include <cmath>
|
|
|
|
namespace mapnik {
|
|
|
|
struct RGBAPolicy
|
|
{
|
|
const static unsigned MAX_LEVELS = 6;
|
|
const static unsigned MIN_ALPHA = 5;
|
|
const static unsigned MAX_ALPHA = 250;
|
|
inline static unsigned index_from_level(unsigned level, rgba const& c)
|
|
{
|
|
unsigned shift = 7 - level;
|
|
return (((c.a >> shift) & 1) << 3)
|
|
| (((c.r >> shift) & 1) << 2)
|
|
| (((c.g >> shift) & 1) << 1)
|
|
| ((c.b >> shift) & 1);
|
|
}
|
|
};
|
|
|
|
template <typename T, typename InsertPolicy = RGBAPolicy >
|
|
class hextree : private mapnik::noncopyable
|
|
{
|
|
struct node
|
|
{
|
|
node ()
|
|
: reds(0),
|
|
greens(0),
|
|
blues(0),
|
|
alphas(0),
|
|
count(0),
|
|
pixel_count(0),
|
|
children_count(0)
|
|
{
|
|
memset(&children_[0],0,sizeof(children_));
|
|
}
|
|
|
|
~node ()
|
|
{
|
|
for (unsigned i = 0; i < 16; ++i)
|
|
{
|
|
if (children_[i] != 0)
|
|
{
|
|
delete children_[i];
|
|
children_[i]=0;
|
|
}
|
|
}
|
|
}
|
|
|
|
bool is_leaf() const
|
|
{
|
|
return (children_count == 0);
|
|
}
|
|
node * children_[16];
|
|
// sum of values for computing mean value using count or pixel_count
|
|
double reds;
|
|
double greens;
|
|
double blues;
|
|
double alphas;
|
|
// if count!=0, then node represents color in output palette
|
|
int count;
|
|
// number of pixels represented by this subtree
|
|
unsigned pixel_count;
|
|
// penalty of using this node as color
|
|
double reduce_cost;
|
|
// number of !=0 positions in children_ array
|
|
byte children_count;
|
|
};
|
|
|
|
// highest reduce_cost first
|
|
struct node_rev_cmp
|
|
{
|
|
bool operator() (const node * lhs, const node* rhs) const
|
|
{
|
|
if (lhs->reduce_cost != rhs->reduce_cost)
|
|
{
|
|
return (lhs->reduce_cost > rhs->reduce_cost);
|
|
}
|
|
return (lhs > rhs);
|
|
}
|
|
};
|
|
|
|
unsigned max_colors_;
|
|
unsigned colors_;
|
|
// flag indicating existance of invisible pixels (a < InsertPolicy::MIN_ALPHA)
|
|
bool has_holes_;
|
|
const std::unique_ptr<node> root_;
|
|
// working palette for quantization, sorted on mean(r,g,b,a) for easier searching NN
|
|
std::vector<rgba> sorted_pal_;
|
|
// index remaping of sorted_pal_ indexes to indexes of returned image palette
|
|
std::vector<unsigned> pal_remap_;
|
|
// rgba hashtable for quantization
|
|
mutable rgba_hash_table color_hashmap_;
|
|
// gamma correction to prioritize dark colors (>1.0)
|
|
double gamma_;
|
|
// look up table for gamma correction
|
|
double gammaLUT_[256];
|
|
// transparency handling
|
|
enum transparency_mode_t {NO_TRANSPARENCY=0, BINARY_TRANSPARENCY=1, FULL_TRANSPARENCY=2};
|
|
unsigned trans_mode_;
|
|
|
|
inline double gamma(double b, double g) const
|
|
{
|
|
return 255 * std::pow(b/255, g);
|
|
}
|
|
|
|
public:
|
|
explicit hextree(unsigned max_colors=256, double g=2.0)
|
|
: max_colors_(max_colors),
|
|
colors_(0),
|
|
has_holes_(false),
|
|
root_(new node()),
|
|
#ifdef USE_DENSE_HASH_MAP
|
|
// TODO - test for any benefit to initializing at a larger size
|
|
color_hashmap_(),
|
|
#endif
|
|
trans_mode_(FULL_TRANSPARENCY)
|
|
{
|
|
setGamma(g);
|
|
#ifdef USE_DENSE_HASH_MAP
|
|
color_hashmap_.set_empty_key(0);
|
|
#endif
|
|
}
|
|
|
|
~hextree()
|
|
{}
|
|
|
|
void setMaxColors(unsigned max_colors)
|
|
{
|
|
max_colors_ = max_colors;
|
|
}
|
|
|
|
void setGamma(double g)
|
|
{
|
|
gamma_ = g;
|
|
for (unsigned i=0; i<256; i++)
|
|
{
|
|
gammaLUT_[i] = gamma(i, 1/gamma_);
|
|
}
|
|
}
|
|
|
|
void setTransMode(unsigned t)
|
|
{
|
|
trans_mode_ = t;
|
|
}
|
|
|
|
transparency_mode_t getTransMode() const
|
|
{
|
|
return trans_mode_;
|
|
}
|
|
|
|
// process alpha value based on trans_mode_
|
|
byte preprocessAlpha(byte a) const
|
|
{
|
|
switch(trans_mode_)
|
|
{
|
|
case NO_TRANSPARENCY:
|
|
return 255;
|
|
case BINARY_TRANSPARENCY:
|
|
return a<127?0:255;
|
|
default:
|
|
return a;
|
|
}
|
|
}
|
|
|
|
void insert(T const& data)
|
|
{
|
|
byte a = preprocessAlpha(data.a);
|
|
unsigned level = 0;
|
|
node * cur_node = root_.get();
|
|
if (a < InsertPolicy::MIN_ALPHA)
|
|
{
|
|
has_holes_ = true;
|
|
return;
|
|
}
|
|
while (true)
|
|
{
|
|
cur_node->pixel_count++;
|
|
cur_node->reds += gammaLUT_[data.r];
|
|
cur_node->greens += gammaLUT_[data.g];
|
|
cur_node->blues += gammaLUT_[data.b];
|
|
cur_node->alphas += a;
|
|
|
|
if (level == InsertPolicy::MAX_LEVELS)
|
|
{
|
|
if (cur_node->pixel_count == 1)
|
|
{
|
|
++colors_;
|
|
}
|
|
break;
|
|
}
|
|
|
|
unsigned idx = InsertPolicy::index_from_level(level,data);
|
|
if (cur_node->children_[idx] == 0)
|
|
{
|
|
cur_node->children_count++;
|
|
cur_node->children_[idx] = new node();
|
|
}
|
|
cur_node = cur_node->children_[idx];
|
|
++level;
|
|
}
|
|
}
|
|
|
|
// return color index in returned earlier palette
|
|
int quantize(unsigned val) const
|
|
{
|
|
byte a = preprocessAlpha(U2ALPHA(val));
|
|
unsigned ind=0;
|
|
if (a < InsertPolicy::MIN_ALPHA || colors_ == 0)
|
|
{
|
|
return 0;
|
|
}
|
|
if (colors_ == 1)
|
|
{
|
|
return pal_remap_[has_holes_?1:0];
|
|
}
|
|
|
|
rgba_hash_table::iterator it = color_hashmap_.find(val);
|
|
if (it == color_hashmap_.end())
|
|
{
|
|
rgba c(val);
|
|
int dr, dg, db, da;
|
|
int dist, newdist;
|
|
|
|
// find closest match based on mean of r,g,b,a
|
|
#if BOOST_VERSION >= 104600
|
|
std::vector<rgba>::const_iterator pit =
|
|
boost::lower_bound(sorted_pal_, c, rgba::mean_sort_cmp());
|
|
#else
|
|
std::vector<rgba>::const_iterator pit =
|
|
std::lower_bound(sorted_pal_.begin(),sorted_pal_.end(), c, rgba::mean_sort_cmp());
|
|
#endif
|
|
ind = pit-sorted_pal_.begin();
|
|
if (ind == sorted_pal_.size())
|
|
ind--;
|
|
dr = sorted_pal_[ind].r - c.r;
|
|
dg = sorted_pal_[ind].g - c.g;
|
|
db = sorted_pal_[ind].b - c.b;
|
|
da = sorted_pal_[ind].a - a;
|
|
dist = dr*dr + dg*dg + db*db + da*da;
|
|
int poz = ind;
|
|
|
|
// search neighbour positions in both directions for better match
|
|
for (int i = poz - 1; i >= 0; i--)
|
|
{
|
|
dr = sorted_pal_[i].r - c.r;
|
|
dg = sorted_pal_[i].g - c.g;
|
|
db = sorted_pal_[i].b - c.b;
|
|
da = sorted_pal_[i].a - a;
|
|
// stop criteria based on properties of used sorting
|
|
if (((dr+db+dg+da) * (dr+db+dg+da) / 4 > dist))
|
|
{
|
|
break;
|
|
}
|
|
newdist = dr*dr + dg*dg + db*db + da*da;
|
|
if (newdist < dist)
|
|
{
|
|
ind = i;
|
|
dist = newdist;
|
|
}
|
|
}
|
|
for (unsigned i = poz + 1; i < sorted_pal_.size(); i++)
|
|
{
|
|
dr = sorted_pal_[i].r - c.r;
|
|
dg = sorted_pal_[i].g - c.g;
|
|
db = sorted_pal_[i].b - c.b;
|
|
da = sorted_pal_[i].a - a;
|
|
// stop criteria based on properties of used sorting
|
|
if ((dr+db+dg+da) * (dr+db+dg+da) / 4 > dist)
|
|
{
|
|
break;
|
|
}
|
|
newdist = dr*dr + dg*dg + db*db + da*da;
|
|
if (newdist < dist)
|
|
{
|
|
ind = i;
|
|
dist = newdist;
|
|
}
|
|
}
|
|
//put found index in hash map
|
|
color_hashmap_[val] = ind;
|
|
}
|
|
else
|
|
{
|
|
ind = it->second;
|
|
}
|
|
|
|
return pal_remap_[ind];
|
|
}
|
|
|
|
void create_palette(std::vector<rgba> & palette)
|
|
{
|
|
sorted_pal_.clear();
|
|
if (has_holes_)
|
|
{
|
|
max_colors_--;
|
|
sorted_pal_.push_back(rgba(0,0,0,0));
|
|
}
|
|
assign_node_colors();
|
|
|
|
sorted_pal_.reserve(colors_);
|
|
create_palette_rek(sorted_pal_, root_.get());
|
|
|
|
// sort palette for binary searching in quantization
|
|
#if BOOST_VERSION >= 104600
|
|
boost::sort(sorted_pal_, rgba::mean_sort_cmp());
|
|
#else
|
|
std::sort(sorted_pal_.begin(), sorted_pal_.end(), rgba::mean_sort_cmp());
|
|
#endif
|
|
// returned palette is rearanged, so that colors with a<255 are at the begining
|
|
pal_remap_.resize(sorted_pal_.size());
|
|
palette.clear();
|
|
palette.reserve(sorted_pal_.size());
|
|
for (unsigned i=0; i<sorted_pal_.size(); ++i)
|
|
{
|
|
if (sorted_pal_[i].a<255)
|
|
{
|
|
pal_remap_[i] = static_cast<unsigned>(palette.size());
|
|
palette.push_back(sorted_pal_[i]);
|
|
}
|
|
}
|
|
for (unsigned i=0; i<sorted_pal_.size(); ++i)
|
|
{
|
|
if (sorted_pal_[i].a==255)
|
|
{
|
|
pal_remap_[i] = static_cast<unsigned>(palette.size());
|
|
palette.push_back(sorted_pal_[i]);
|
|
}
|
|
}
|
|
}
|
|
|
|
private:
|
|
|
|
void print_tree(node *r, int d=0, int id=0) const
|
|
{
|
|
for (int i=0; i<d; i++)
|
|
{
|
|
printf("\t");
|
|
}
|
|
if (r->count>0)
|
|
{
|
|
printf("%d: (+%d/%d/%.5f) (%d %d %d %d)\n",
|
|
id, (int)r->count, (int)r->pixel_count, r->reduce_cost,
|
|
(int)round(gamma(r->reds / r->count, gamma_)),
|
|
(int)round(gamma(r->greens / r->count, gamma_)),
|
|
(int)round(gamma(r->blues / r->count, gamma_)),
|
|
(int)(r->alphas / r->count));
|
|
}
|
|
else
|
|
{
|
|
printf("%d: (%d/%d/%.5f) (%d %d %d %d)\n", id,
|
|
(int)r->count, (int)r->pixel_count, r->reduce_cost,
|
|
(int)round(gamma(r->reds / r->pixel_count, gamma_)),
|
|
(int)round(gamma(r->greens / r->pixel_count, gamma_)),
|
|
(int)round(gamma(r->blues / r->pixel_count, gamma_)),
|
|
(int)(r->alphas / r->pixel_count));
|
|
}
|
|
for (unsigned idx=0; idx < 16; ++idx)
|
|
{
|
|
if (r->children_[idx] != 0)
|
|
{
|
|
print_tree(r->children_[idx], d+1, idx);
|
|
}
|
|
}
|
|
}
|
|
|
|
// traverse tree and search for nodes with count!=0, that represent single color.
|
|
// clip extreme alfa values
|
|
void create_palette_rek(std::vector<rgba> & palette, node * itr) const
|
|
{
|
|
if (itr->count >= 3)
|
|
{
|
|
unsigned count = itr->count;
|
|
byte a = byte(itr->alphas/float(count));
|
|
if (a > InsertPolicy::MAX_ALPHA) a = 255;
|
|
if (a < InsertPolicy::MIN_ALPHA) a = 0;
|
|
palette.push_back(rgba((byte)round(gamma(itr->reds / count, gamma_)),
|
|
(byte)round(gamma(itr->greens / count, gamma_)),
|
|
(byte)round(gamma(itr->blues / count, gamma_)), a));
|
|
}
|
|
for (unsigned idx=0; idx < 16; ++idx)
|
|
{
|
|
if (itr->children_[idx] != 0)
|
|
{
|
|
create_palette_rek(palette, itr->children_[idx]);
|
|
}
|
|
}
|
|
}
|
|
|
|
// assign value to r, representing some penalty for assigning one
|
|
// color to all pixels in this subtree
|
|
void compute_cost(node *r)
|
|
{
|
|
//initial small value, so that all nodes have >0 cost
|
|
r->reduce_cost = r->pixel_count/1000.0;
|
|
if (r->children_count==0)
|
|
{
|
|
return;
|
|
}
|
|
// mean color of all pixels in subtree
|
|
double mean_r = r->reds / r->pixel_count;
|
|
double mean_g = r->greens / r->pixel_count;
|
|
double mean_b = r->blues / r->pixel_count;
|
|
double mean_a = r->alphas / r->pixel_count;
|
|
for (unsigned idx=0; idx < 16; ++idx)
|
|
{
|
|
if (r->children_[idx] != 0)
|
|
{
|
|
double dr,dg,db,da;
|
|
compute_cost(r->children_[idx]);
|
|
// include childrens penalty
|
|
r->reduce_cost += r->children_[idx]->reduce_cost;
|
|
// difference between mean value and subtree mean value
|
|
dr = r->children_[idx]->reds / r->children_[idx]->pixel_count - mean_r;
|
|
dg = r->children_[idx]->greens / r->children_[idx]->pixel_count - mean_g;
|
|
db = r->children_[idx]->blues / r->children_[idx]->pixel_count - mean_b;
|
|
da = r->children_[idx]->alphas / r->children_[idx]->pixel_count - mean_a;
|
|
// penalty_x = d_x^2 * pixel_count * mean_alfa/255, where x=r,g,b,a
|
|
// mean_alpha/255 because more opaque color = more noticable differences
|
|
r->reduce_cost += (dr*dr + dg*dg + db*db + da*da) * r->children_[idx]->alphas / 255;
|
|
}
|
|
}
|
|
}
|
|
|
|
// starting from root_, unfold nodes with biggest penalty
|
|
// until all available colors are assigned to processed nodes
|
|
void assign_node_colors()
|
|
{
|
|
compute_cost(root_.get());
|
|
|
|
int tries = 0;
|
|
|
|
// at the begining, single color assigned to root_
|
|
colors_ = 1;
|
|
root_->count = root_->pixel_count;
|
|
|
|
std::set<node*,node_rev_cmp> colored_leaves_heap;
|
|
colored_leaves_heap.insert(root_.get());
|
|
while((!colored_leaves_heap.empty() && (colors_ < max_colors_) && (tries < 16)))
|
|
{
|
|
// select worst node to remove it from palette and replace with children
|
|
node * cur_node = *colored_leaves_heap.begin();
|
|
colored_leaves_heap.erase(colored_leaves_heap.begin());
|
|
if (((cur_node->children_count + colors_ - 1) > max_colors_))
|
|
{
|
|
tries++;
|
|
continue; // try few times, maybe next will have less children
|
|
}
|
|
tries = 0;
|
|
// ignore leaves and also nodes with small mean error and not excessive number of pixels
|
|
if (cur_node->pixel_count > 0 &&
|
|
(cur_node->children_count > 0) &&
|
|
(((cur_node->reduce_cost / cur_node->pixel_count + 1) * std::log(double(cur_node->pixel_count))) > 15)
|
|
)
|
|
{
|
|
colors_--;
|
|
cur_node->count = 0;
|
|
for (unsigned idx=0; idx < 16; ++idx)
|
|
{
|
|
if (cur_node->children_[idx] != 0)
|
|
{
|
|
node *n = cur_node->children_[idx];
|
|
n->count = n->pixel_count;
|
|
colored_leaves_heap.insert(n);
|
|
colors_++;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
};
|
|
} // namespace mapnik
|
|
|
|
#endif // MAPNIK_HEXTREE_HPP
|