540 lines
18 KiB
C++
540 lines
18 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2006 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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//$Id$
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#ifndef MAPNIK_PNG_IO_HPP
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#define MAPNIK_PNG_IO_HPP
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#include <mapnik/global.hpp>
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#include <mapnik/octree.hpp>
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#include <mapnik/hextree.hpp>
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#include <mapnik/global.hpp>
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extern "C"
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{
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#include <png.h>
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}
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#define MAX_OCTREE_LEVELS 4
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#ifdef MAPNIK_BIG_ENDIAN
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#define U2RED(x) (((x)>>24)&0xff)
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#define U2GREEN(x) (((x)>>16)&0xff)
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#define U2BLUE(x) (((x)>>8)&0xff)
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#define U2ALPHA(x) ((x)&0xff)
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#else
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#define U2RED(x) ((x)&0xff)
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#define U2GREEN(x) (((x)>>8)&0xff)
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#define U2BLUE(x) (((x)>>16)&0xff)
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#define U2ALPHA(x) (((x)>>24)&0xff)
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#endif
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namespace mapnik {
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template <typename T>
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void write_data (png_structp png_ptr, png_bytep data, png_size_t length)
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{
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T * out = static_cast<T*>(png_get_io_ptr(png_ptr));
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out->write(reinterpret_cast<char*>(data), length);
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}
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template <typename T>
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void flush_data (png_structp png_ptr)
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{
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T * out = static_cast<T*>(png_get_io_ptr(png_ptr));
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out->flush();
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}
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template <typename T1, typename T2>
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void save_as_png(T1 & file , T2 const& image)
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{
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png_voidp error_ptr=0;
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png_structp png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
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error_ptr,0, 0);
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if (!png_ptr) return;
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// switch on optimization only if supported
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#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) && defined(PNG_MMX_CODE_SUPPORTED)
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png_uint_32 mask, flags;
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flags = png_get_asm_flags(png_ptr);
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mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
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png_set_asm_flags(png_ptr, flags | mask);
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#endif
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png_set_filter (png_ptr, 0, PNG_FILTER_NONE);
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png_infop info_ptr = png_create_info_struct(png_ptr);
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if (!info_ptr)
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{
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png_destroy_write_struct(&png_ptr,(png_infopp)0);
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return;
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}
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if (setjmp(png_jmpbuf(png_ptr)))
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{
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return;
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}
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png_set_write_fn (png_ptr, &file, &write_data<T1>, &flush_data<T1>);
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//png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
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//png_set_compression_strategy(png_ptr, Z_FILTERED);
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png_set_IHDR(png_ptr, info_ptr,image.width(),image.height(),8,
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PNG_COLOR_TYPE_RGB_ALPHA,PNG_INTERLACE_NONE,
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PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
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png_write_info(png_ptr, info_ptr);
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for (unsigned i=0;i<image.height();i++)
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{
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png_write_row(png_ptr,(png_bytep)image.getRow(i));
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}
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png_write_end(png_ptr, info_ptr);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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}
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template <typename T>
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void reduce_8 (T const& in, image_data_8 & out, octree<rgb> trees[], unsigned limits[], unsigned levels, std::vector<unsigned> & alpha)
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{
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unsigned width = in.width();
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unsigned height = in.height();
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//unsigned alphaCount[alpha.size()];
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std::vector<unsigned> alphaCount(alpha.size());
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for(unsigned i=0; i<alpha.size(); i++)
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{
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alpha[i] = 0;
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alphaCount[i] = 0;
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}
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for (unsigned y = 0; y < height; ++y)
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{
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mapnik::image_data_32::pixel_type const * row = in.getRow(y);
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mapnik::image_data_8::pixel_type * row_out = out.getRow(y);
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for (unsigned x = 0; x < width; ++x)
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{
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unsigned val = row[x];
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mapnik::rgb c(U2RED(val), U2GREEN(val), U2BLUE(val));
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byte index = 0;
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int idx = -1;
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for(int j=levels-1; j>0; j--){
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if (U2ALPHA(val)>=limits[j] && trees[j].colors()>0) {
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index = idx = trees[j].quantize(c);
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break;
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}
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}
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if (idx>=0 && idx<(int)alpha.size())
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{
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alpha[idx]+=U2ALPHA(val);
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alphaCount[idx]++;
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}
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row_out[x] = index;
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}
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}
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for(unsigned i=0; i<alpha.size(); i++)
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{
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if (alphaCount[i]!=0)
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alpha[i] /= alphaCount[i];
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}
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}
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template <typename T>
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void reduce_4 (T const& in, image_data_8 & out, octree<rgb> trees[], unsigned limits[], unsigned levels, std::vector<unsigned> & alpha)
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{
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unsigned width = in.width();
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unsigned height = in.height();
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//unsigned alphaCount[alpha.size()];
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std::vector<unsigned> alphaCount(alpha.size());
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for(unsigned i=0; i<alpha.size(); i++)
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{
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alpha[i] = 0;
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alphaCount[i] = 0;
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}
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for (unsigned y = 0; y < height; ++y)
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{
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mapnik::image_data_32::pixel_type const * row = in.getRow(y);
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mapnik::image_data_8::pixel_type * row_out = out.getRow(y);
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for (unsigned x = 0; x < width; ++x)
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{
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unsigned val = row[x];
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mapnik::rgb c(U2RED(val), U2GREEN(val), U2BLUE(val));
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byte index = 0;
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int idx=-1;
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for(int j=levels-1; j>0; j--){
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if (U2ALPHA(val)>=limits[j] && trees[j].colors()>0) {
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index = idx = trees[j].quantize(c);
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break;
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}
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}
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if (idx>=0 && idx<(int)alpha.size())
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{
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alpha[idx]+=U2ALPHA(val);
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alphaCount[idx]++;
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}
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if (x%2 == 0) index = index<<4;
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row_out[x>>1] |= index;
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}
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}
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for(unsigned i=0; i<alpha.size(); i++)
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{
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if (alphaCount[i]!=0)
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alpha[i] /= alphaCount[i];
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}
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}
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// 1-bit but only one color.
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template <typename T>
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void reduce_1(T const&, image_data_8 & out, octree<rgb> trees[], unsigned limits[], std::vector<unsigned> & alpha)
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{
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out.set(0); // only one color!!!
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}
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template <typename T>
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void save_as_png(T & file, std::vector<mapnik::rgb> & palette,
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mapnik::image_data_8 const& image,
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unsigned width,
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unsigned height,
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unsigned color_depth,
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std::vector<unsigned> &alpha)
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{
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png_voidp error_ptr=0;
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png_structp png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
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error_ptr,0, 0);
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if (!png_ptr) return;
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// switch on optimization only if supported
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#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) && defined(PNG_MMX_CODE_SUPPORTED)
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png_uint_32 mask, flags;
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flags = png_get_asm_flags(png_ptr);
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mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
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png_set_asm_flags(png_ptr, flags | mask);
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#endif
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png_set_filter (png_ptr, 0, PNG_FILTER_NONE);
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png_infop info_ptr = png_create_info_struct(png_ptr);
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if (!info_ptr)
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{
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png_destroy_write_struct(&png_ptr,(png_infopp)0);
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return;
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}
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if (setjmp(png_jmpbuf(png_ptr)))
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{
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png_destroy_write_struct(&png_ptr, &info_ptr);
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return;
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}
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png_set_write_fn (png_ptr, &file, &write_data<T>, &flush_data<T>);
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png_set_IHDR(png_ptr, info_ptr,width,height,color_depth,
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PNG_COLOR_TYPE_PALETTE,PNG_INTERLACE_NONE,
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PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
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png_set_PLTE(png_ptr,info_ptr,reinterpret_cast<png_color*>(&palette[0]),palette.size());
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// make transparent lowest indexes, so tRNS is small
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if (alpha.size()>0)
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{
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std::vector<png_byte> trans(alpha.size());
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unsigned alphaSize=0;//truncate to nonopaque values
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for(unsigned i=0; i < alpha.size(); i++)
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{
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trans[i]=alpha[i];
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if (alpha[i]<255)
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alphaSize = i+1;
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}
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if (alphaSize>0)
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png_set_tRNS(png_ptr, info_ptr, (png_bytep)&trans[0], alphaSize, 0);
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}
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png_write_info(png_ptr, info_ptr);
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for (unsigned i=0;i<height;i++)
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{
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png_write_row(png_ptr,(png_bytep)image.getRow(i));
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}
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png_write_end(png_ptr, info_ptr);
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png_destroy_write_struct(&png_ptr, &info_ptr);
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}
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template <typename T1,typename T2>
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void save_as_png256(T1 & file, T2 const& image, const unsigned max_colors = 256, int trans_mode = -1)
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{
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// number of alpha ranges in png256 format; 2 results in smallest image with binary transparency
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// 3 is minimum for semitransparency, 4 is recommended, anything else is worse
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const unsigned TRANSPARENCY_LEVELS = (trans_mode==2||trans_mode<0)?MAX_OCTREE_LEVELS:2;
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unsigned width = image.width();
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unsigned height = image.height();
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unsigned alphaHist[256];//transparency histogram
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unsigned semiCount = 0;//sum of semitransparent pixels
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unsigned meanAlpha = 0;
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for(int i=0; i<256; i++){
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alphaHist[i] = 0;
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}
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for (unsigned y = 0; y < height; ++y){
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for (unsigned x = 0; x < width; ++x){
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unsigned val = U2ALPHA((unsigned)image.getRow(y)[x]);
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if (trans_mode==0)
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val=255;
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alphaHist[val]++;
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meanAlpha += val;
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if (val>0 && val<255)
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semiCount++;
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}
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}
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meanAlpha /= width*height;
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// transparency ranges division points
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unsigned limits[MAX_OCTREE_LEVELS+1];
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limits[0] = 0;
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limits[1] = (alphaHist[0]>0)?1:0;
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limits[TRANSPARENCY_LEVELS] = 256;
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unsigned alphaHistSum = 0;
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for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++)
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limits[j] = limits[1];
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for(unsigned i=1; i<256; i++){
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alphaHistSum += alphaHist[i];
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for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++){
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if (alphaHistSum<semiCount*(j)/4)
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limits[j] = i;
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}
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}
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// avoid too wide full transparent range
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if (limits[1]>256/(TRANSPARENCY_LEVELS-1))
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limits[1]=256/(TRANSPARENCY_LEVELS-1);
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// avoid too wide full opaque range
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if (limits[TRANSPARENCY_LEVELS-1]<212)
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limits[TRANSPARENCY_LEVELS-1]=212;
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if (TRANSPARENCY_LEVELS==2) {
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limits[1]=127;
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}
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// estimated number of colors from palette assigned to chosen ranges
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unsigned cols[MAX_OCTREE_LEVELS];
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// count colors
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for(unsigned j=1; j<=TRANSPARENCY_LEVELS; j++) {
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cols[j-1] = 0;
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for(unsigned i=limits[j-1]; i<limits[j]; i++){
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cols[j-1] += alphaHist[i];
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}
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}
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unsigned divCoef = width*height-cols[0];
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if (divCoef==0) divCoef = 1;
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cols[0] = cols[0]>0?1:0; // fully transparent color (one or not at all)
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if (max_colors>=64) {
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// give chance less populated but not empty cols to have at least few colors(12)
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unsigned minCols = (12+1)*divCoef/(max_colors-cols[0]);
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for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++) if (cols[j]>12 && cols[j]<minCols) {
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divCoef += minCols-cols[j];
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cols[j] = minCols;
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}
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}
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unsigned usedColors = cols[0];
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for(unsigned j=1; j<TRANSPARENCY_LEVELS-1; j++){
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cols[j] = cols[j]*(max_colors-cols[0])/divCoef;
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usedColors += cols[j];
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}
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// use rest for most opaque group of pixels
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cols[TRANSPARENCY_LEVELS-1] = max_colors-usedColors;
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//no transparency
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if (trans_mode == 0)
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{
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limits[1] = 0;
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cols[0] = 0;
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cols[1] = max_colors;
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}
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// octree table for separate alpha range with 1-based index (0 is fully transparent: no color)
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octree<rgb> trees[MAX_OCTREE_LEVELS];
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for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++)
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trees[j].setMaxColors(cols[j]);
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for (unsigned y = 0; y < height; ++y)
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{
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typename T2::pixel_type const * row = image.getRow(y);
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for (unsigned x = 0; x < width; ++x)
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{
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unsigned val = row[x];
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// insert to proper tree based on alpha range
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for(unsigned j=TRANSPARENCY_LEVELS-1; j>0; j--){
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if (cols[j]>0 && U2ALPHA(val)>=limits[j]) {
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trees[j].insert(mapnik::rgb(U2RED(val), U2GREEN(val), U2BLUE(val)));
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break;
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}
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}
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}
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}
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unsigned leftovers = 0;
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std::vector<rgb> palette;
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palette.reserve(max_colors);
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if (cols[0])
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palette.push_back(rgb(0,0,0));
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for(unsigned j=1; j<TRANSPARENCY_LEVELS; j++) {
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if (cols[j]>0) {
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if (leftovers>0) {
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cols[j] += leftovers;
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trees[j].setMaxColors(cols[j]);
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leftovers = 0;
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}
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std::vector<rgb> pal;
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trees[j].setOffset(palette.size());
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trees[j].create_palette(pal);
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assert(pal.size() <= max_colors);
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leftovers = cols[j]-pal.size();
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cols[j] = pal.size();
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for(unsigned i=0; i<pal.size(); i++){
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palette.push_back(pal[i]);
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}
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assert(palette.size() <= 256);
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}
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}
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//transparency values per palette index
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std::vector<unsigned> alphaTable;
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//alphaTable.resize(palette.size());//allow semitransparency also in almost opaque range
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if (trans_mode != 0)
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alphaTable.resize(palette.size() - cols[TRANSPARENCY_LEVELS-1]);
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if (palette.size() > 16 )
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{
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// >16 && <=256 colors -> write 8-bit color depth
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image_data_8 reduced_image(width,height);
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reduce_8(image, reduced_image, trees, limits, TRANSPARENCY_LEVELS, alphaTable);
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save_as_png(file,palette,reduced_image,width,height,8,alphaTable);
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}
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else if (palette.size() == 1)
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{
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// 1 color image -> write 1-bit color depth PNG
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unsigned image_width = (int(0.125*width) + 7)&~7;
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unsigned image_height = height;
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image_data_8 reduced_image(image_width,image_height);
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reduce_1(image,reduced_image,trees, limits, alphaTable);
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if (meanAlpha<255 && cols[0]==0) {
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alphaTable.resize(1);
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alphaTable[0] = meanAlpha;
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}
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save_as_png(file,palette,reduced_image,width,height,1,alphaTable);
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}
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else
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{
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// <=16 colors -> write 4-bit color depth PNG
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unsigned image_width = (int(0.5*width) + 3)&~3;
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unsigned image_height = height;
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image_data_8 reduced_image(image_width,image_height);
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reduce_4(image, reduced_image, trees, limits, TRANSPARENCY_LEVELS, alphaTable);
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save_as_png(file,palette,reduced_image,width,height,4,alphaTable);
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}
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}
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template <typename T1,typename T2>
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void save_as_png256_hex(T1 & file, T2 const& image, int colors = 256, int trans_mode = -1, double gamma = 2.0)
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{
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unsigned width = image.width();
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unsigned height = image.height();
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// structure for color quantization
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hextree<mapnik::rgba> tree(colors);
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if (trans_mode >= 0)
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tree.setTransMode(trans_mode);
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if (gamma > 0)
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tree.setGamma(gamma);
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for (unsigned y = 0; y < height; ++y)
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{
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typename T2::pixel_type const * row = image.getRow(y);
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for (unsigned x = 0; x < width; ++x)
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{
|
|
unsigned val = row[x];
|
|
tree.insert(mapnik::rgba(U2RED(val), U2GREEN(val), U2BLUE(val), U2ALPHA(val)));
|
|
}
|
|
}
|
|
|
|
//transparency values per palette index
|
|
std::vector<mapnik::rgba> pal;
|
|
tree.create_palette(pal);
|
|
assert(int(pal.size()) <= colors);
|
|
|
|
std::vector<mapnik::rgb> palette;
|
|
std::vector<unsigned> alphaTable;
|
|
for(unsigned i=0; i<pal.size(); i++)
|
|
{
|
|
palette.push_back(rgb(pal[i].r, pal[i].g, pal[i].b));
|
|
alphaTable.push_back(pal[i].a);
|
|
}
|
|
|
|
if (palette.size() > 16 )
|
|
{
|
|
// >16 && <=256 colors -> write 8-bit color depth
|
|
image_data_8 reduced_image(width, height);
|
|
|
|
for (unsigned y = 0; y < height; ++y)
|
|
{
|
|
mapnik::image_data_32::pixel_type const * row = image.getRow(y);
|
|
mapnik::image_data_8::pixel_type * row_out = reduced_image.getRow(y);
|
|
|
|
for (unsigned x = 0; x < width; ++x)
|
|
{
|
|
unsigned val = row[x];
|
|
mapnik::rgba c(U2RED(val), U2GREEN(val), U2BLUE(val), U2ALPHA(val));
|
|
row_out[x] = tree.quantize(c);
|
|
}
|
|
}
|
|
save_as_png(file, palette, reduced_image, width, height, 8, alphaTable);
|
|
}
|
|
else if (palette.size() == 1)
|
|
{
|
|
// 1 color image -> write 1-bit color depth PNG
|
|
unsigned image_width = (int(0.125*width) + 7)&~7;
|
|
unsigned image_height = height;
|
|
image_data_8 reduced_image(image_width, image_height);
|
|
reduced_image.set(0);
|
|
save_as_png(file, palette, reduced_image, width, height, 1, alphaTable);
|
|
}
|
|
else
|
|
{
|
|
// <=16 colors -> write 4-bit color depth PNG
|
|
unsigned image_width = (int(0.5*width) + 3)&~3;
|
|
unsigned image_height = height;
|
|
image_data_8 reduced_image(image_width, image_height);
|
|
for (unsigned y = 0; y < height; ++y)
|
|
{
|
|
mapnik::image_data_32::pixel_type const * row = image.getRow(y);
|
|
mapnik::image_data_8::pixel_type * row_out = reduced_image.getRow(y);
|
|
byte index = 0;
|
|
|
|
for (unsigned x = 0; x < width; ++x)
|
|
{
|
|
unsigned val = row[x];
|
|
mapnik::rgba c(U2RED(val), U2GREEN(val), U2BLUE(val), U2ALPHA(val));
|
|
index = tree.quantize(c);
|
|
if (x%2 == 0) index = index<<4;
|
|
row_out[x>>1] |= index;
|
|
}
|
|
}
|
|
save_as_png(file, palette, reduced_image, width, height, 4, alphaTable);
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif // MAPNIK_PNG_IO_HPP
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