/*
 * lpsclinv.c: Invert Log Polar Mapping.
 *
 *   May.15,'94. Oshiro.
 *   Oct. 6,'94. Oshiro. 入力ファイルの形式を ppm にした．
 */

static char rcsid[]="$Id: lpsclinv.c,v 1.1 1995/05/10 18:19:27 oshiro Exp oshiro $";

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

#define EXIT_SUCCESS 0
#define EXIT_FAILURE 1

int main(int argc, char **argv)
{
	FILE *fp;
	int width, height;
	int last_width, last_height;
	long x, y;
	int uwidth, vwidth;
	int img_type, depth;
	long u, v;
	long len;
	double r, logmaxr;
	double th; 
	char *data;
	char *fname;
	
	if (argc != 3 && argc != 4 ) {
		fprintf(stderr, "Usage: lpsclinv width height [infile]\n");
		exit(EXIT_FAILURE);
	}
	width =atoi(argv[1]);
	height=atoi(argv[2]);
	if (argc==4) {
		fname=argv[3];
		fp=OpenAndCheckPPMFile(fname, &img_type, &uwidth, &vwidth, &depth);
		if (fp==NULL) {
			fprintf(stderr, "lpsclinv: Incorrect ppm file (%s).\n",
				fname);
			exit(EXIT_FAILURE);
		}
	} else {
		fp=stdin;
		if (CheckPPMFile(fp, &img_type, &uwidth, &vwidth, &depth)!=0) {
			fprintf(stderr, "lpsclinv: Incorrect ppm file (stdin).\n");
			exit(EXIT_FAILURE);
		}
	}
	data=malloc(sizeof(char)*(long)vwidth*uwidth*3);
	if (data == NULL) {
		fprintf(stderr, "Fatal: Not enough memory.\n");
		exit(EXIT_FAILURE);
	}
	len=fread(data, sizeof(char), (long)vwidth*uwidth*3, fp);
	fclose(fp);
	if (len < vwidth*uwidth) {
		fprintf(stderr, "Warning: Not enough data.\n");
	}
	
	printf("P6\n%d %d\n255\n", width, height);
/*	logmaxr=log(sqrt(width/2*width/2 + height/2*height/2));*/
	    /* 上の式だと中心部が拡大されて変換される．*/
/*	logmaxr=log(((width<height)? width:height)/2);*/
	logmaxr=log(((width>height)? width:height)/2);
	    /* 上の式だと元画像と同じ大きさ（？？チェックするべし！）で */
	    /* 周辺部が円になって変換される．*/
	last_height=height/2+(height%2);
	last_width =width /2+(width %2);
	for (y=height/2; y>-last_height; y--) {
		for (x=-width/2; x<last_width; x++) {
			r=sqrt(x*x + y*y);
			if (r < 1.0) {
				putchar(0);
				putchar(0);
				putchar(0);
				continue;
			}
			th=atan2(y, x);
			u=(int)(log(r)/logmaxr*uwidth);
			v=(int)(th/M_PI*vwidth/2+vwidth/2);
			/*	    fprintf(stderr, "%d %d %d %d\n", x, y, u, v);
			 */	    if (u==uwidth) u=0;
			if (v==vwidth) v=0;
			if (u<0 || u>uwidth || v<0 || v>vwidth) {
				putchar(0);
				putchar(0);
				putchar(0);
				continue;
			}
			
			putchar(data[v*(uwidth*3) + u*3  ]);
			putchar(data[v*(uwidth*3) + u*3+1]);
			putchar(data[v*(uwidth*3) + u*3+2]);
		}
		/*	fprintf(stderr, "\n");
		 */    }
	
	return(EXIT_SUCCESS); 
}