// @(#)root/img_view:$Id$
// Author: Jerzy Tarasiuk	19/06/2009
{ // see http://root.cern.ch/root/html/tutorials/proof/getProof.C.html
//
//_________________________________________________________________
//
// img_view	- view a graphical image as 2-dimensional histogram
//
// Reads a graphical image (allowed typed are: GIF, JPEG, PNG, TIFF)
// puts its data in a histogram and shows it;
// to be run as root session, with the image filename,
// and other arguments passed as environment variables.
//
//#include "Getline.h"
//#include "TEnv.h"
//#include "TString.h"
//#include "TSystem.h"
	gROOT->Reset(); // import sys;
	int ix, iy, iz, hx, hy, sc, ixm, iym, izm, hxm, hym;
	double ac,bc,ll,ul,dpi,z; char *img, *ixp, *ipn=NULL;
	const char *xan[]={ "a", "b", "ll", "ul", "img", "dpi", "sc", NULL };
//	void *xav[]=	{   &ac, &bc, &ll,  &ul,  &img,  &dpi,  &sc };
	const char xat[]="ddddsdi";
	const char *itn[]={ "gif", "jpg", "png", "tif" };
	const char *itp[]={ "gif", "jpeg", "png","tiff" };
	FILE* pfd; char buf[1024],*cp,*ibf; int i,tc; long idc;


	// 1. process args (passed as environment variables)
	// 1.1. verify they all were specified
	for(i=0; xan[i]!=NULL; i++) {
		if((cp=gSystem->Getenv(xan[i]))==NULL) break;
//		switch(xat[i]) {
//		case's': *(char**)xav[i]=cp; break;
//		case'i': *(int*)(xav[i])=atol(cp); break;
//			sscanf(cp, "%d", xav[i]); break;
//		case'd': *(double*)(xav[i])=atof(cp); break;
//			sscanf(cp, "%lf", xav[i]); break;
//		}
	}
	if(xan[i]!=NULL) {
		cerr << "\nName not found: " << xan[i] << "\n\n";
		cerr << "Usage: name1=value1 name2=value2 [...] root program.C\n\n";
		cerr << "Required names: a, b, ll, ul, img, dpi, sc; where:\n";
		cerr << "a and b are for data linear transformation: z=a*data+b\n";
		cerr << "ll and ul are lower and upper limit for the data\n";
		cerr << "img is input image, types handled: gif jpg png tif\n";
		cerr << "sc is reduction factor (int); dpi is image dot density\n\n";
		exit(-1);
	}
	// 1.2. get and convert their values
	ac=atof(gSystem->Getenv("a")); bc=atof(gSystem->Getenv("b"));
	ll=atof(gSystem->Getenv("ll")); ul=atof(gSystem->Getenv("ul"));
	img=gSystem->Getenv("img");
	dpi=atof(gSystem->Getenv("dpi")); sc=atoi(gSystem->Getenv("sc"));

	// 1.3. show these args
	cout << "a=" << ac << ", b=" << bc;
	cout << ", ll=" << ll << ", ul=" << ul << "\n";
	cout << "dpi=" << dpi;
	cout << ", sc=" << sc;
	cout << ", img=" << img << "\n";

	// 1.4. are args values correct?
	if(sc<1) { cerr << "sc must be 1 or more\n"; exit(-1); }
	if(dpi<20) { cerr << "dpi unreasonably small\n"; exit(-1); }
	if((ixp=strrchr(img,'.'))!=NULL) ixp++;
	else { cerr << "img without extension??\n"; exit(-1); }
	cout << "ixp=" << ixp << "\n";
	if(ixp!=NULL) for(i=0; i<4; i++) {
		if(strcmp(ixp, itn[i])==0 || strcmp(ixp, itp[i])==0)
			{ ipn=itp[i]; break; }
	}
	if(ipn) cout << "Image processor: " << ipn << "topnm\n";
	else { cerr << "No processor for such an image\n"; exit(-1); }


	// 2. get image header (will read image data later)
	sprintf(buf, "%stopnm %s | ppmtopgm", ipn, img);
	pfd=gSystem->OpenPipe(buf,"r");
	for(i=0; i<3; i++) if(fgets(buf, sizeof(buf), pfd)!=NULL) switch(i) {
	case 0: if(strcmp(buf,"P5\n")) { cerr << "Bad image header type: " << buf; exit(-1); } break;
	case 1: if(sscanf(buf,"%d%d", &ixm, &iym)==2) break;
		cerr << "Image header error, buf=" << buf; exit(-1);
	case 2: if(sscanf(buf,"%d", &izm)==1) break;
		cerr << "Image header error, buf=" << buf; exit(-1);
	} hxm=ixm/sc; hym=iym/sc;
	cout << "ixm=" << ixm << ", iym=" << iym << ", izm=" << izm << "\n";


	// 3. make the histogram
	// 3.1. histogram setup
	TCanvas *c1 = new TCanvas("c1"," ",1);
	TH2F *h2 = new TH2F("h2","cap",hxm,0,hxm*sc*25.4/dpi,hym,0,hym*sc*25.4/dpi);
	h2->SetXTitle(" X [mm]");
	h2->SetYTitle(" Y [mm]");
	h2->SetZTitle("Neutron dose relative units");
	h2->GetZaxis()->SetTitleOffset(1.4);
	h2->GetXaxis()->SetTitleOffset(1.5);
	h2->GetYaxis()->SetTitleOffset(1.5);
	cout << "histogram setup done\n";

	// 3.2. get image data and put it in the histogram
	if((ibf=malloc(ixm))==NULL) { cerr << "malloc() failed\n"; exit(-1); }
	for(idc=iy=0; iy<iym; iy++) {
		fread(ibf, ixm, 1, pfd); hy=iy/sc;
		for(ix=0; ix<ixm; ix++) {
			hx=ix/sc; idc++;
			// here is a place alike to make changes
			iz=izm-(unsigned char)ibf[ix];	// use negative
			// the original value is 0 for black, izm for white dot
			// need just reverse, so use izm-dot_value
			z=ac*iz+bc;			// linear scaling
			// maybe -log(dot_value/izm) would be more "physical"?
			if(z>ul) z=ul; if(z<ll) z=ll;	// data limits
			// to limit impact of unreasonable data
			h2->SetBinContent(hx,hy,z/sc/sc
			+h2->GetBinContent(hx,hy));	// sum in histogram
	}	}	
	gSystem->ClosePipe(pfd); cout << idc << " data points used\n";

	// 3.3. show the histogram
	gPad->SetLeftMargin(0.15);
	h2->Draw("lego");
} // http://root.cern.ch/root/html/tutorials/tree/basic.C.html