/* sum_of_images.c */
#include <stdio.h>
#include <stdlib.h>
#include "mypgm.h"

main( )
{
  int number;
  int i, x, y;
  int **image3;
  int min, max;

  printf("Let's sum up images with the same size\n");
  printf("Enter the number of images : ");
  scanf("%d", &number);

  /* load the first image */
  printf("\n1-th image input:\n");
  load_image_data( );
  x_size2 = x_size1;
  y_size2 = y_size1;

  /* dynamic memory allocation */
  image3 = (int **)malloc(y_size2 * sizeof(int *));
  for (y = 0; y < y_size2; y++)
    image3[y] = (int *)malloc(x_size2 * sizeof(int));

  for (y = 0; y < y_size2; y++)
    for (x = 0; x < x_size2; x++)
      image3[y][x] = image1[y][x];
  
  /* load the remaining images */
  for (i = 2; i <= number; i++) {
    printf("\n%d-th image input:\n", i);
    load_image_data( );
    for (y = 0; y < y_size2; y++)
      for (x = 0; x < x_size2; x++)
	image3[y][x] += image1[y][x];
  }

  min = max = image3[0][0];
  for (y = 0; y < y_size2; y++) {
    for (x = 0; x < x_size2; x++) {
      if (image3[y][x] < min) min = image3[y][x];
      if (image3[y][x] > max) max = image3[y][x]; 
    }
  }

  if (max == min) {
    printf("Nothing exists!!!\n");
    exit(1);
  }

  if (max <= MAX_BRIGHTNESS) {
    for (y = 0; y < y_size2; y++)
      for (x = 0; x < x_size2; x++)
	image2[y][x] = (unsigned char)image3[y][x];
  } else {
    for (y = 0; y < y_size2; y++) {
      for (x = 0; x < x_size2; x++) {
	image2[y][x] = (unsigned char)((image3[y][x] - min) * MAX_BRIGHTNESS
				       / (max - min));
      }
    }
  }

  save_image_data( );     /* Output image save */

  free(image3);

  return 0;
}