/* ----------------------------------------
Image Processing pb1.c
Gray Image Pattern Generation
Quad area paint image 255/192/80/0
Ichinoseki National College Advanced Course
------------------------------------------ */

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

main(argc,argv)
int argc;
char *argv[]; 
{
	static int  i,j,m;
	static int pixel,line;
	FILE *fp1;

	/* Command parameter check  */
	if (argc!=4){
		printf("Usage : command pixel line output_file\n");
		return 1;
	}
	/* Image size parameter load */
	sscanf(argv[1],"%d",&pixel);
	sscanf(argv[2],"%d",&line);

	/* Output image file name read */
	if (( fp1=fopen(argv[3],"w") )==NULL){
		printf("Can't open output_file\n");
		return 1;
	}

	/* ppm header output */
	fprintf(fp1,"P5\n");
	fprintf(fp1,"# INCT\n");
	fprintf(fp1,"%s %s\n",argv[1],argv[2]);
	fprintf(fp1,"255\n");

	/* Gray image generate */
	for (j=0; j < line; j++)
	{
	for (i=0; i < pixel; i++)
	{
		if (i <=pixel/4){
		m=255;
		}
		else if (pixel/4 < i && i <= 2*pixel/4){
		m=192;
		}
		else if (2*pixel/4 < i && i <= 3*pixel/4){
		m=80;
		}
		else{
		m=0;
		}
		putc(m,fp1);
	}
	}
	fclose(fp1);
	return 0;
}