236 lines
8 KiB
C++
236 lines
8 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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#include <mapnik/global.hpp>
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#include <mapnik/octree.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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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, ImageData8 & out, octree<rgb> & tree)
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{
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unsigned width = in.width();
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unsigned height = in.height();
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for (unsigned y = 0; y < height; ++y)
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{
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mapnik::ImageData32::pixel_type const * row = in.getRow(y);
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mapnik::ImageData8::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((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff);
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byte index = tree.quantize(c);
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row_out[x] = index;
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}
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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, ImageData8 & out, octree<rgb> & tree)
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{
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unsigned width = in.width();
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unsigned height = in.height();
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for (unsigned y = 0; y < height; ++y)
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{
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mapnik::ImageData32::pixel_type const * row = in.getRow(y);
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mapnik::ImageData8::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((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff);
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byte index = tree.quantize(c);
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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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}
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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&, ImageData8 & out, octree<rgb> &)
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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::ImageData8 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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{
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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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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)
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{
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octree<rgb> tree(256);
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unsigned width = image.width();
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unsigned height = image.height();
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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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tree.insert(mapnik::rgb((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff));
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}
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}
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std::vector<rgb> palette;
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tree.create_palette(palette);
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assert(palette.size() <= 256);
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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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ImageData8 reduced_image(width,height);
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reduce_8(image,reduced_image,tree);
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save_as_png(file,palette,reduced_image,width,height,8);
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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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ImageData8 reduced_image(image_width,image_height);
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reduce_1(image,reduced_image,tree);
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save_as_png(file,palette,reduced_image,width,height,1);
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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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ImageData8 reduced_image(image_width,image_height);
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reduce_4(image,reduced_image,tree);
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save_as_png(file,palette,reduced_image,width,height,4);
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}
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}
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}
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