jpeg_reader.tpp
/*
CLAW - a C++ Library Absolutely Wonderful
CLAW is a free library without any particular aim but being useful to
anyone.
Copyright (C) 2005-2011 Julien Jorge
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
contact: julien.jorge@gamned.org
*/
/**
* \file jpeg_reader.tpp
* \brief Implementation of the template methods of the
* claw::graphic::jpeg::reader class.
* \author Julien Jorge
*/
#include <claw/jpeg_error_manager.hpp>
#include <claw/exception.hpp>
/*----------------------------------------------------------------------------*/
/**
* \brief Decompress a RGB jpeg image.
* \param cinfo Informations about the decompression process.
* \param pixel_convert Operator to use to convert pixels from input.
*/
template<class Convert>
void claw::graphic::jpeg::reader::read_data
( jpeg_decompress_struct& cinfo, const Convert& pixel_convert )
{
const unsigned int pixel_size = cinfo.output_components;
JSAMPLE* buffer = new JSAMPLE[cinfo.output_width * pixel_size];
error_manager jerr;
jpeg_error_mgr* jerr_saved = cinfo.err;
cinfo.err = jpeg_std_error(&jerr.pub);
jerr.pub.error_exit = jpeg__error_manager__error_exit;
if ( setjmp(jerr.setjmp_buffer) )
{
delete[] buffer;
throw CLAW_EXCEPTION(jerr.error_string);
}
while (cinfo.output_scanline < cinfo.output_height)
{
jpeg_read_scanlines(&cinfo, &buffer, 1);
scanline::iterator pixel = m_image[cinfo.output_scanline-1].begin();
for ( unsigned int i=0; i!=pixel_size*m_image.width();
i+=pixel_size, ++pixel )
*pixel = pixel_convert( &buffer[i] );
}
delete[] buffer;
cinfo.err = jerr_saved;
} // jpeg::reader::read_data()