source: sans/utils/Teabag/sa_mutil.c @ 1249

#include <stdio.h>
#include <stdlib.h>


int **imatrix (long nr, long nc) {
  int i;
  int **m;

  m=(int **) malloc((size_t)(nr * sizeof(int *)));
  if (!m) { fprintf(stderr,"imatrix: allocation failure 1 \n"); exit(1); }

  m[0] = (int *) malloc((size_t)((nr*nc)*sizeof(int)));
  if (!m[0]) { fprintf(stderr,"imatrix: allocation failure 2\n"); exit(1); }

  for (i=1;i<nc;i++) m[i] = m[i - 1] + nc;
  return m;
}

unsigned char **ucmatrix (long nr, long nc) {
  int i;
  unsigned char **m;

  m=(unsigned char **) malloc((size_t)(nr * sizeof(unsigned char *)));
  if (!m) { fprintf(stderr,"ucmatrix: allocation failure 1 \n"); exit(1); }

  m[0] = (unsigned char *) malloc((size_t)((nr*nc)*sizeof(unsigned char)));
  if (!m[0]) { fprintf(stderr,"ucmatrix: allocation failure 2\n"); exit(1); }

  for (i=1;i<nc;i++) m[i] = m[i - 1] + nc;
  return m;
}



int
int2uchar(int **input, unsigned char **output, int width, int height){
  int x,y;
  double loval, hival, valrange;

  loval = 1e20; hival = -1e20;
  for(y=0;y<height;y++){
    for(x=0;x<width;x++){
      if (input[y][x] < loval) loval = input[y][x];
      if (input[y][x] > hival) hival = input[y][x];
    }
  }

  valrange = hival - loval;

  for(y=0;y<height;y++){
    for(x=0;x<width;x++){
      if (valrange == 0.0) {
        output[y][x] = 0;
      } else {
        output[y][x] = (unsigned char) 255 * ((input[y][x]-loval)/valrange);
      }
    }
  }
  return 0;
}