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

void move_av_filtering()
     /* Spatial filtering of image data */
     /* Moving average filter */
     /* input: image1[y][x] -------- output: image2[y][x]   */
{
  int x, y, i, j;    /* loop variable */
  int mean;   /* mean value in 3x3 mask */
  int count;  /* no. of pixels in 3x3 mask */
  
  x_size2 = x_size1;
  y_size2 = y_size1;

  /* filtering operation */
  for (y = 0; y < y_size1; y++) {
    for (x = 0; x < x_size1; x++) {
      mean = 0;
      count = 0;
      for (j = -1; j <= 1; j++) {
	for (i = -1; i <= 1; i++) {
	  if (y+j >= 0 && y+j < y_size1 && x+i >= 0 && x+i < x_size1) {
	    mean += image1[y+j][x+i];
	    count++;
	  }
	}
      }
      mean /= count;
      image2[y][x] = (unsigned char)mean;
    }
  }
}

main()
{
  load_image_data();   /* Input of image1 */
  move_av_filtering(); /* Moving average filtering is applied to image1 */
  save_image_data();   /* Output of image2 */
  return 0;
}