Image viewer

ROOT
1

Hello,

I am creating a whole bunch of TImages (~100) and at some point I need to have a quick look at all of them before continuing to process the information they contain. I neither want to save them all and then browse them with an external viewer, nor do I want to open a hundred canvases, nor do I want to create one canvas with 100 thumbnails. The best thing would be to load them all into one Canvas or GUI and screen them with a “previous” and a “next” button.

Since, I am sure something like this is already out there, I would like to know what you would recommend for me to use.

Thanks for your input

Greg

2

I am not aware of a such application build on top of ROOT. But ROOT has all the tools to implement it.

3

You can find a short script showImages.C below viewing images in a directory. Read comments.

Rene

TCanvas *c2 = 0;
void showOne();

void showImages(const char *ftype=".jpg")
{
   //this script scans the current directory for all files containing the string ftype in the name (default is .jpg)
   //a canvas is created and divided in as many subpads as images found in the directory.
   //when moving the mouse of a pad thumbnail, a zoomed view of the image appears.
   //Author:: Rene Brun

   const char *path = ".";
   void *dir = gSystem->OpenDirectory(path);
   if (!dir) {
      printf("invalid directory name: %s\n",path);
      return;
   }
   TList *files = new TList();
   const char *afile, *afilefull, *hname;
   TFile *f;
   Int_t fn = 0;
   char fname[20];
   TNamed *f;
   while ((afile = gSystem->GetDirEntry(dir))) {
      if (!strstr(afile,ftype)) continue;
      afilefull = Form("%s/%s",path,afile);
      printf("\n\nopening file: %s\n",afilefull);
      fn++;
      sprintf(fname,"f%d",fn);
      f = new TNamed(fname,afilefull);
      files->Add(f);
   }
   //we divide the canvas in sqrt(fn) files
   if (fn <= 0) {
      printf("no files named %s in this directory\n");
      return;
   }
   TImage *images[1000];
   Int_t ndiv = (Int_t)TMath::Sqrt(fn)+1;
   TCanvas *c1 = new TCanvas("c1","c1",800,800);
   c1->Divide(ndiv,ndiv);
   for (Int_t i=0;i<fn;i++) {
      c1->cd(i+1);
      f = (TNamed*)files->At(i);
      images[i] = TImage::Open(f->GetTitle());
      images[i]->SetConstRatio(kFALSE);
      images[i]->Draw("x");
   }
   
   c1->AddExec("showone","showOne()");
      
   gSystem->FreeDirectory(dir);
}

void showOne() {
   TObject *select = gPad->GetSelected();
   if(!select) return;
   if (!select->InheritsFrom("TImage")) return;
   printf("pad=%s, select=%s\n",gPad->GetName(),select->GetName());
   if (!c2) c2 = new TCanvas("c2","c2",850,10,600,600);
   c2->cd();
   c2->Clear();
   select->Draw();
   c2->Update();
}