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 /*

  #

  #  File        : use_jpeg_buffer.cpp

  #                ( C++ source file )

  #

  #  Description : Example of use for the CImg plugin 'plugins/jpeg_buffer.h'.

  #                This file is a part of the CImg Library project.

  #                ( http://cimg.sourceforge.net )

  #

  #  Copyright   : Paolo Prete

  #                ( p4olo_prete(at)yahoo.it )

  #

  #  License     : CeCILL v2.0

  #                ( http://www.cecill.info/licences/Licence_CeCILL_V2-en.html )

  #

  #  This software is governed by the CeCILL  license under French law and

  #  abiding by the rules of distribution of free software.  You can  use,

  #  modify and/ or redistribute the software under the terms of the CeCILL

  #  license as circulated by CEA, CNRS and INRIA at the following URL

  #  "http://www.cecill.info".

  #

  #  As a counterpart to the access to the source code and  rights to copy,

  #  modify and redistribute granted by the license, users are provided only

  #  with a limited warranty  and the software's author,  the holder of the

  #  economic rights,  and the successive licensors  have only  limited

  #  liability.

  #

  #  In this respect, the user's attention is drawn to the risks associated

  #  with loading,  using,  modifying and/or developing or reproducing the

  #  software by the user in light of its specific status of free software,

  #  that may mean  that it is complicated to manipulate,  and  that  also

  #  therefore means  that it is reserved for developers  and  experienced

  #  professionals having in-depth computer knowledge. Users are therefore

  #  encouraged to load and test the software's suitability as regards their

  #  requirements in conditions enabling the security of their systems and/or

  #  data to be ensured and,  more generally, to use and operate it in the

  #  same conditions as regards security.

  #

  #  The fact that you are presently reading this means that you have had

  #  knowledge of the CeCILL license and that you accept its terms.

  #

 */

 // These includes are necessary to get the plug-in compile !

 #include <cstdio>

 #include <jpeglib.h>

 #include <jerror.h>

 // Define plugin and include the CImg Library.

 #define cimg_plugin "plugins/jpeg_buffer.h"

 #include "CImg.h"

 using namespace cimg_library;

 // The lines below are necessary when using a non-standard compiler as visualcpp6.

 #ifdef cimg_use_visualcpp6

 #define std

 #endif

 // Main procedure

 //----------------

 int main() {

   // Create a jpeg memory buffer from the content of a jpeg file.

   // (this is for testing purposes only)

   const char *filename_input = "foo.jpg";

   std::fprintf(stderr," - Reading file '%s'\n",filename_input);

   std::FILE *file_input = std::fopen(filename_input,"rb");

   if (!file_input) { std::fprintf(stderr,"Input JPEG file not found !"); std::exit(0); }

   std::fprintf(stderr," - Construct input JPEG-coded buffer\n");

   unsigned buf_size = 500000; // Put the file size here !

   JOCTET *buffer_input = new JOCTET[buf_size];

   std::fread(buffer_input,sizeof(JOCTET),buf_size,file_input);

   std::fclose(file_input);

   // -> 'buffer_input' is now a valid jpeg-coded memory buffer.

   // Create a CImg instance from the jpeg-coded buffer using the plug-in function.

   std::fprintf(stderr," - Create CImg instance from JPEG-coded buffer\n");

   CImg<unsigned char> img;

   img.load_jpeg_buffer(buffer_input, buf_size);

   delete[] buffer_input;

   // Do you image processing stuff here ....

   // Here, we just mirror the image and write "hello".

   std::fprintf(stderr," - Do simple processing\n");

   const unsigned char purple[] = { 255, 0, 0 };

   const unsigned char black[] = { 0, 0, 0 };

   img.mirror('y').draw_text(0,0,"   Hello!   ",purple,black,1,57);

   // Display image to see if everything's fine.

   img.display("Using 'jpeg_buffer.h' plugin");

   // Define a new JOCTET array where the processed image has to be saved

   // (we don't know its dimension before compressing it, therefore we have to allocate enough memory )

   std::fprintf(stderr," - Construct output JPEG-coded buffer\n");

   JOCTET *buffer_output = new JOCTET[2*buf_size];

   // Save processed image into this JOCTET buffer, compressed as jpeg.

   // This is done again by using the plug-in function.

   img.save_jpeg_buffer(buffer_output,buf_size,60);

   // Note that here, the variable 'buf_size' contains the length of the

   // data which have been written in the given output buffer.

   // Copy the content of the above array into a new file

   // (it should give you a valid JPEG file then !)

   const char *filename_output = "foo_output.jpg";

   std::fprintf(stderr," - Save output file '%s'\n",filename_output);

   std::FILE* file_output = std::fopen(filename_output,"wb");

   std::fwrite(buffer_output, sizeof(JOCTET), buf_size, file_output);

   std::fclose(file_output);

   delete[] buffer_output;

   std::fprintf(stderr," - All done !\n");

   return 0;

 }