mapnik/include/mapnik/jpeg_io.hpp
2011-01-13 18:45:40 +00:00

137 lines
4.1 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
*
*****************************************************************************/
//$Id$
#ifndef MAPNIK_JPEG_IO_HPP
#define MAPNIK_JPEG_IO_HPP
#if defined(HAVE_JPEG)
#include <mapnik/global.hpp>
extern "C"
{
#include <jpeglib.h>
}
namespace mapnik {
#define BUFFER_SIZE 4096
typedef struct
{
struct jpeg_destination_mgr pub;
std::ostream * out;
JOCTET * buffer;
} dest_mgr;
inline void init_destination( j_compress_ptr cinfo)
{
dest_mgr * dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
dest->buffer = (JOCTET*) (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
BUFFER_SIZE * sizeof(JOCTET));
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = BUFFER_SIZE;
}
inline boolean empty_output_buffer (j_compress_ptr cinfo)
{
dest_mgr * dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
dest->out->write((char*)dest->buffer, BUFFER_SIZE);
if (!*(dest->out)) return false;
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = BUFFER_SIZE;
return true;
}
inline void term_destination( j_compress_ptr cinfo)
{
dest_mgr * dest = reinterpret_cast<dest_mgr*>(cinfo->dest);
size_t size = BUFFER_SIZE - dest->pub.free_in_buffer;
if (size > 0)
{
dest->out->write((char*)dest->buffer, size);
}
dest->out->flush();
}
template <typename T1, typename T2>
void save_as_jpeg(T1 & file,int quality, T2 const& image)
{
struct jpeg_compress_struct cinfo;
struct jpeg_error_mgr jerr;
int width=image.width();
int height=image.height();
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_compress(&cinfo);
cinfo.dest = (struct jpeg_destination_mgr *)(*cinfo.mem->alloc_small)
((j_common_ptr) &cinfo, JPOOL_PERMANENT, sizeof(dest_mgr));
dest_mgr * dest = (dest_mgr*) cinfo.dest;
dest->pub.init_destination = init_destination;
dest->pub.empty_output_buffer = empty_output_buffer;
dest->pub.term_destination = term_destination;
dest->out = &file;
//jpeg_stdio_dest(&cinfo, fp);
cinfo.image_width = width;
cinfo.image_height = height;
cinfo.input_components = 3;
cinfo.in_color_space = JCS_RGB;
jpeg_set_defaults(&cinfo);
jpeg_set_quality(&cinfo, quality,1);
jpeg_start_compress(&cinfo, 1);
JSAMPROW row_pointer[1];
JSAMPLE* row=reinterpret_cast<JSAMPLE*>( ::operator new (sizeof(JSAMPLE) * width*3));
while (cinfo.next_scanline < cinfo.image_height)
{
const unsigned* imageRow=image.getRow(cinfo.next_scanline);
int index=0;
for (int i=0;i<width;++i)
{
#ifdef MAPNIK_BIG_ENDIAN
row[index++]=(imageRow[i]>>24)&0xff;
row[index++]=(imageRow[i]>>16)&0xff;
row[index++]=(imageRow[i]>>8)&0xff;
#else
row[index++]=(imageRow[i])&0xff;
row[index++]=(imageRow[i]>>8)&0xff;
row[index++]=(imageRow[i]>>16)&0xff;
#endif
}
row_pointer[0] = &row[0];
(void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
}
::operator delete(row);
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
}
}
#endif
#endif // MAPNIK_JPEG_IO_HPP