JPEGCompressor.h

/*  JPEG class wrapper to ijg libjpeg library
 
    Copyright (C) 2000-2025 Ruven Pillay.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
 
    This program 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 General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software Foundation,
    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
 
 
 
#ifndef _JPEGCOMPRESSOR_H
#define _JPEGCOMPRESSOR_H
 
 
#include "Compressor.h"
 
 
// Fix missing snprintf in Windows
#if _MSC_VER
#define snprintf _snprintf
#endif
 
 
extern "C"{
/* Undefine this to prevent compiler warning
 */
#undef HAVE_STDLIB_H
#include <jpeglib.h>
}
 
 
 
typedef struct {
 
  struct jpeg_destination_mgr pub;   
 
  unsigned char* source;             
  size_t source_size;                
  size_t written;                    
  unsigned int strip_height;         
 
} iip_destination_mgr;
 
 
 
class JPEGCompressor: public Compressor{
 
 private:
 
  unsigned int width, height, channels;
 
  struct jpeg_compress_struct cinfo;
  struct jpeg_error_mgr jerr;
  iip_destination_mgr dest_mgr;
  iip_destination_mgr* dest;
 
  void writeResolution();
 
  void writeICCProfile();
 
  void writeXMPMetadata();
 
  void writeExifMetadata();
 
 
 public:
 
 
  JPEGCompressor( int quality ) : Compressor(quality), dest(NULL) {
    dest = &dest_mgr;
  };
 
 
 
  inline void setQuality( int factor ) {
 
    // Flag that user has manually changed quality level
    default_quality = false;
 
    if( factor < 0 ) Q = 0;
    else if( factor > 100 ) Q = 100;
    else Q = factor;
  };
 
 
 
 
  void InitCompression( const RawTile& rawtile, unsigned int strip_height );
 
 
  unsigned int CompressStrip( unsigned char* s, unsigned char* o, unsigned int tile_height );
 
 
  unsigned int Finish( unsigned char* output );
 
 
  unsigned int Compress( RawTile& t );
 
  inline const char* getMimeType() const { return "image/jpeg"; }
 
  inline const char* getSuffix() const { return "jpg"; }
 
  inline ImageEncoding getImageEncoding() const { return ImageEncoding::JPEG; };
 
 
  void injectMetadata( RawTile& r );
 
};
 
 
#endif