mapnik/include/mapnik/png_io.hpp

254 lines
8.4 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2006 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
*
*****************************************************************************/
//$Id$
#include <mapnik/global.hpp>
#include <mapnik/octree.hpp>
extern "C"
{
#include <png.h>
}
namespace mapnik {
template <typename T>
void write_data (png_structp png_ptr, png_bytep data, png_size_t length)
{
T * out = static_cast<T*>(png_get_io_ptr(png_ptr));
out->write(reinterpret_cast<char*>(data), length);
}
template <typename T>
void flush_data (png_structp png_ptr)
{
T * out = static_cast<T*>(png_get_io_ptr(png_ptr));
out->flush();
}
template <typename T1, typename T2>
void save_as_png(T1 & file , T2 const& image)
{
png_voidp error_ptr=0;
png_structp png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
error_ptr,0, 0);
if (!png_ptr) return;
// switch on optimization only if supported
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) && defined(PNG_MMX_CODE_SUPPORTED)
png_uint_32 mask, flags;
flags = png_get_asm_flags(png_ptr);
mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
png_set_asm_flags(png_ptr, flags | mask);
#endif
png_set_filter (png_ptr, 0, PNG_FILTER_NONE);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
png_destroy_write_struct(&png_ptr,(png_infopp)0);
return;
}
if (setjmp(png_jmpbuf(png_ptr)))
{
png_destroy_write_struct(&png_ptr, &info_ptr);
return;
}
png_set_write_fn (png_ptr, &file, &write_data<T1>, &flush_data<T1>);
//png_set_compression_level(png_ptr, Z_BEST_COMPRESSION);
//png_set_compression_strategy(png_ptr, Z_FILTERED);
png_set_IHDR(png_ptr, info_ptr,image.width(),image.height(),8,
PNG_COLOR_TYPE_RGB_ALPHA,PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
png_write_info(png_ptr, info_ptr);
for (unsigned i=0;i<image.height();i++)
{
png_write_row(png_ptr,(png_bytep)image.getRow(i));
}
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
}
template <typename T>
void reduce_8 (T const& in, ImageData8 & out, octree<rgb> & tree)
{
unsigned width = in.width();
unsigned height = in.height();
for (unsigned y = 0; y < height; ++y)
{
mapnik::ImageData32::pixel_type const * row = in.getRow(y);
mapnik::ImageData8::pixel_type * row_out = out.getRow(y);
for (unsigned x = 0; x < width; ++x)
{
unsigned val = row[x];
mapnik::rgb c((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff);
byte index = tree.quantize(c);
if (!((val>>24)&0x80)) index = 0;//alfa
row_out[x] = index;
}
}
}
template <typename T>
void reduce_4 (T const& in, ImageData8 & out, octree<rgb> & tree)
{
unsigned width = in.width();
unsigned height = in.height();
for (unsigned y = 0; y < height; ++y)
{
mapnik::ImageData32::pixel_type const * row = in.getRow(y);
mapnik::ImageData8::pixel_type * row_out = out.getRow(y);
for (unsigned x = 0; x < width; ++x)
{
unsigned val = row[x];
mapnik::rgb c((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff);
byte index = tree.quantize(c);
if (x%2 > 0) index = index<<4;
if (!((val>>24)&0x80)) index = 0;//alfa
row_out[x>>1] |= index;
}
}
}
// 1-bit but only one color.
template <typename T>
void reduce_1(T const&, ImageData8 & out, octree<rgb> &)
{
out.set(0); // only one color!!!
}
template <typename T>
void save_as_png(T & file, std::vector<mapnik::rgb> & palette,
mapnik::ImageData8 const& image,
unsigned width,
unsigned height,
unsigned color_depth,
bool hasAlfa)
{
png_voidp error_ptr=0;
png_structp png_ptr=png_create_write_struct(PNG_LIBPNG_VER_STRING,
error_ptr,0, 0);
if (!png_ptr) return;
// switch on optimization only if supported
#if defined(PNG_LIBPNG_VER) && (PNG_LIBPNG_VER >= 10200) && defined(PNG_MMX_CODE_SUPPORTED)
png_uint_32 mask, flags;
flags = png_get_asm_flags(png_ptr);
mask = png_get_asm_flagmask(PNG_SELECT_READ | PNG_SELECT_WRITE);
png_set_asm_flags(png_ptr, flags | mask);
#endif
png_set_filter (png_ptr, 0, PNG_FILTER_NONE);
png_infop info_ptr = png_create_info_struct(png_ptr);
if (!info_ptr)
{
png_destroy_write_struct(&png_ptr,(png_infopp)0);
return;
}
if (setjmp(png_jmpbuf(png_ptr)))
{
png_destroy_write_struct(&png_ptr, &info_ptr);
return;
}
png_set_write_fn (png_ptr, &file, &write_data<T>, &flush_data<T>);
png_set_IHDR(png_ptr, info_ptr,width,height,color_depth,
PNG_COLOR_TYPE_PALETTE,PNG_INTERLACE_NONE,
PNG_COMPRESSION_TYPE_DEFAULT,PNG_FILTER_TYPE_DEFAULT);
png_set_PLTE(png_ptr,info_ptr,reinterpret_cast<png_color*>(&palette[0]),palette.size());
// make transparent lowest indexes, so tRNS is small
if (hasAlfa)
{
byte trans[] = {0,0,0,0};
//png_color_16p unused;
png_set_tRNS(png_ptr, info_ptr, (png_bytep)trans, 1, NULL);
}
png_write_info(png_ptr, info_ptr);
for (unsigned i=0;i<height;i++)
{
png_write_row(png_ptr,(png_bytep)image.getRow(i));
}
png_write_end(png_ptr, info_ptr);
png_destroy_write_struct(&png_ptr, &info_ptr);
}
template <typename T1,typename T2>
void save_as_png256(T1 & file, T2 const& image)
{
octree<rgb> tree(256);
unsigned width = image.width();
unsigned height = image.height();
for (unsigned y = 0; y < height; ++y)
{
typename T2::pixel_type const * row = image.getRow(y);
for (unsigned x = 0; x < width; ++x)
{
unsigned val = row[x];
if ((val>>24)&0x80)
{
tree.insert(mapnik::rgb((val)&0xff, (val>>8)&0xff, (val>>16) & 0xff));
}
else
{
tree.hasAlfa(true);
}
}
}
std::vector<rgb> palette;
tree.create_palette(palette);
assert(palette.size() <= 256);
if (palette.size() > 16 )
{
// >16 && <=256 colors -> write 8-bit color depth
ImageData8 reduced_image(width,height);
reduce_8(image,reduced_image,tree);
save_as_png(file,palette,reduced_image,width,height,8,tree.hasAlfa());
}
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;
ImageData8 reduced_image(image_width,image_height);
reduce_1(image,reduced_image,tree);
save_as_png(file,palette,reduced_image,width,height,1,tree.hasAlfa());
}
else
{
// <=16 colors -> write 4-bit color depth PNG
unsigned image_width = (int(0.5*width) + 3)&~3;
unsigned image_height = height;
ImageData8 reduced_image(image_width,image_height);
reduce_4(image,reduced_image,tree);
save_as_png(file,palette,reduced_image,width,height,4,tree.hasAlfa());
}
}
}