doc/v622/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.ch/files\n",fname);

      gal = TFile::Open(Form("http://root.cern.ch/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);

}

Form
char * Form(const char *fmt,...)

gSystem
R__EXTERN TSystem * gSystem
Definition: TSystem.h:556

TAttImage::StartPaletteEditor
virtual void StartPaletteEditor()
Opens a GUI to edit the color palette.
Definition: TAttImage.cxx:780

TAttPad::SetBottomMargin
virtual void SetBottomMargin(Float_t bottommargin)
Set Pad bottom margin in fraction of the pad height.
Definition: TAttPad.cxx:100

TAttPad::SetLeftMargin
virtual void SetLeftMargin(Float_t leftmargin)
Set Pad left margin in fraction of the pad width.
Definition: TAttPad.cxx:110

TAttPad::SetRightMargin
virtual void SetRightMargin(Float_t rightmargin)
Set Pad right margin in fraction of the pad width.
Definition: TAttPad.cxx:120

TAttPad::SetTopMargin
virtual void SetTopMargin(Float_t topmargin)
Set Pad top margin in fraction of the pad height.
Definition: TAttPad.cxx:130

TCanvas
The Canvas class.
Definition: TCanvas.h:27

TCanvas::ToggleEventStatus
virtual void ToggleEventStatus()
Toggle event statusbar.
Definition: TCanvas.cxx:2375

TDirectoryFile::Get
TObject * Get(const char *namecycle) override
Return pointer to object identified by namecycle.
Definition: TDirectoryFile.cxx:908

TFile
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:53

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:3942

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

TImage::Zoom
virtual void Zoom(UInt_t, UInt_t, UInt_t, UInt_t)
Definition: TImage.h:128

TObject::Draw
virtual void Draw(Option_t *option="")
Default Draw method for all objects.
Definition: TObject.cxx:195

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:1291