/* correct140.cpp - applies correction for non-uniform lighting
 */

static char *usage ="\n  usage: %s in.png out.png prr px py p1 [map.png]\n";

#include "imageLib.h"
#include "math.h"
#include <stdlib.h>
#define VERBOSE 1

#define ROUND(x) ((x) >= 0? ((int)((x) + .5)) : ((int)((x) - .5)))

#define SATURATION 251

int main(int argc, char *argv[])
{
    try {
	if (argc < 6)
	    throw CError(usage, argv[0]);
	int argn = 1;
	char *infile = argv[argn++];
	char *outfile = argv[argn++];
	float prr = atof(argv[argn++]);
	float px = atof(argv[argn++]);
	float py = atof(argv[argn++]);
	float p1 = atof(argv[argn++]);
	char *mapfile = (argn < argc) ? argv[argn++] : NULL;

	CByteImage im;
	ReadImageVerb(im, infile, VERBOSE);
	CShape sh = im.Shape();
	int w = sh.width, h = sh.height;
	int s = w/14;
	if (14*s != w || 10*s != h)
	    throw CError("14x10 aspect ratio expected");
	sh.nBands = 1;
	CByteImage map(sh);
	for(int y = 0; y < h; y++){
	    for(int x = 0; x < w; x++){
		float fy = ((float)y - h/2.0) / (float)s;
		float fx = ((float)x - w/2.0) / (float)s;
		float frr = fx * fx + fy * fy;
		float f = prr * frr + px * fx + py * fy + p1;
		for (int b = 0; b < 3; b++){
		    int v = im.Pixel(x, y, b);
		    // don't decrease saturated values
		    if (f <= 1.0 || v < SATURATION)
			im.Pixel(x, y, b) = __min(255, __max(0, ROUND(v / f)));
		}
		map.Pixel(x, y, 0) =
		    __min(255, __max(0, 128 + ROUND(500*(f-1))));
	    }
	}
	WriteImageVerb(im, outfile, VERBOSE);
	if (mapfile)
	    WriteImageVerb(map, mapfile, VERBOSE);
    }
    catch (CError &err) {
	fprintf(stderr, err.message);
	fprintf(stderr, "\n");
	return -1;
    }
  
    return 0;
}