/*
  Sampe code uses JPEG and TIFF library.
  This program reads a tiff image, processes it and output to a jpeg image.
  It is tested on Linux 2.4.
  To compile: gcc -o tiff2jpeg tiff2jpeg.c -ljpeg -ltiff -lm
  
  JPEG library can be obtained from http://www.ijg.org
  TIFF library can be obtained from http://www.libtiff.org
*/

#include <stdio.h>
#include "tiffio.h"
#include "jpeglib.h"

unsigned char **cpicalloc(int row, int col) 
{
  int i;
  unsigned char **p;
  
  p = (unsigned char **) calloc(row,sizeof(unsigned char *));
  if(!p){
    fprintf(stderr,"memory allocation error\n");
    exit(1);
  }
  for(i=0;i<row;i++){
    p[i] = (unsigned char *) calloc(col,sizeof(unsigned char));
    if(!p[i]){
      fprintf(stderr,"memory allocation error\n");
      exit(1);
    }
  }
  return p;
}

main()
{
  TIFF *tiffin;
  FILE *jpegout;
  char file_name[50];
  unsigned char **pic, *scan_line;
  int i, j, width, height, row_stride, quality;
  struct jpeg_compress_struct cinfo;
  struct jpeg_error_mgr jerr;
  JSAMPROW row_pointer[1];

  sprintf(file_name, "%s.tif", "testimg");
  if((tiffin = TIFFOpen(file_name,"r")) == NULL){
    fprintf(stderr, "file open error\n");
    exit(0);
  }

  if(tiffin){
    uint32 w, h;
    size_t npixels;
    uint32* raster;
    TIFFGetField(tiffin, TIFFTAG_IMAGEWIDTH, &w);
    TIFFGetField(tiffin, TIFFTAG_IMAGELENGTH, &h);
    npixels = w*h;
    raster = (uint32*) _TIFFmalloc(npixels*sizeof(uint32));
    width = w;
    height = h;
    pic = cpicalloc(height, width*3);
    if(raster != NULL){
      if(TIFFReadRGBAImage(tiffin, w, h, raster, 0)){
	for(i=0; i<h; i++){
	  for(j=0; j<w; j++){
	    pic[(h-1)-i][j*3] = TIFFGetR(raster[i*w+j]);
	    pic[(h-1)-i][j*3+1] = TIFFGetG(raster[i*w+j]);
	    pic[(h-1)-i][j*3+2] = TIFFGetB(raster[i*w+j]);
	  }
	}
      }
    }
  }
  TIFFClose(tiffin);

  /* Simple Processing (negate the picture) */
  for(i=0; i<height; i++){
    for(j=0; j<width*3; j++){
      pic[i][j] = -pic[i][j];
    }
  }

  sprintf(file_name, "%s.jpg", "output");
  if((jpegout = fopen(file_name, "wb")) == NULL){
    fprintf(stderr, "cannot open %s\n", file_name);
    exit(1);
  }

  cinfo.err = jpeg_std_error(&jerr);
  jpeg_create_compress(&cinfo);
  jpeg_stdio_dest(&cinfo, jpegout);

  cinfo.image_width = width;
  cinfo.image_height = height;
  cinfo.input_components = 3;
  cinfo.in_color_space = JCS_RGB;
  jpeg_set_defaults(&cinfo);

  quality = 70;
  jpeg_set_quality(&cinfo, quality, TRUE);
  jpeg_start_compress(&cinfo, TRUE);
  row_stride = width * 3;

  while(cinfo.next_scanline < cinfo.image_height){
    row_pointer[0] = &pic[cinfo.next_scanline][0];
    (void) jpeg_write_scanlines(&cinfo, row_pointer, 1);
  }
  jpeg_finish_compress(&cinfo);
  fclose(jpegout);
  jpeg_destroy_compress(&cinfo);
}