doc/v636/galaxy__image_8C.html

void galaxy_image()

{

   TCanvas *canv = new TCanvas("image", "n4254", 40, 40, 812, 700);

   canv->ToggleEventStatus();

   canv->SetRightMargin(0.2);

   canv->SetLeftMargin(0.01);

   canv->SetTopMargin(0.01);

   canv->SetBottomMargin(0.01);


   // read the pixel data from file "galaxy.root"

   // the size of the image is 401 X 401 pixels

   const char *fname = "galaxy.root";

   TFile *gal = 0;

   if (!gSystem->AccessPathName(fname)) {

      gal = TFile::Open(fname);

   } else {

      printf("accessing %s file from http://root.cern/files\n", fname);

      gal = TFile::Open(Form("http://root.cern/files/%s", fname));

   }

   if (!gal)

      return;

   TImage *img = (TImage *)gal->Get("n4254");

   img->Draw();


   // open the color editor

   img->StartPaletteEditor();


   // zoom the image

   img->Zoom(80, 80, 250, 250);

}

TRangeDynCast
ROOT::Detail::TRangeCast< T, true > TRangeDynCast
TRangeDynCast is an adapter class that allows the typed iteration through a TCollection.
Definition TCollection.h:358

Form
char * Form(const char *fmt,...)
Formats a string in a circular formatting buffer.
Definition TString.cxx:2489

gSystem
R__EXTERN TSystem * gSystem
Definition TSystem.h:572

ROOT::Detail::TRangeCast
Definition TCollection.h:311

TCanvas
The Canvas class.
Definition TCanvas.h:23

TFile
A ROOT file is an on-disk file, usually with extension .root, that stores objects in a file-system-li...
Definition TFile.h:131

TFile::Open
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition TFile.cxx:4131

TImage
An abstract interface to image processing library.
Definition TImage.h:29

TSystem::AccessPathName
virtual Bool_t AccessPathName(const char *path, EAccessMode mode=kFileExists)
Returns FALSE if one can access a file using the specified access mode.
Definition TSystem.cxx:1308