TGApplication.cxx

Go to the documentation of this file.

// @(#)root/gui:$Id$
// Author: Guy Barrand   30/05/2001
 
/*************************************************************************
 * Copyright (C) 2001, Guy Barrand.                                      *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
 
 
/** \class TGApplication
\ingroup guiwidgets
 
This class initialize the ROOT GUI toolkit.
This class must be instantiated exactly once in any given
application.
 
*/
 
 
#include "RConfigure.h"
 
#include "TGApplication.h"
#include "TROOT.h"
#include "TSystem.h"
#include "TGClient.h"
#include "TPluginManager.h"
#include "TError.h"
#include "TEnv.h"
#include "TVirtualX.h"
#include "TStyle.h"
#include "TInterpreter.h"
#include "TColor.h"
 
 
////////////////////////////////////////////////////////////////////////////////
/// Create a GUI application environment. Use this class if you only
/// want to use the ROOT GUI and no other services. In all other cases
/// use either TApplication or TRint.
 
TGApplication::TGApplication(const char *appClassName,
                             Int_t *argc, char **argv, void*, Int_t)
   : TApplication()
{
   if (gApplication) {
      Error("TGApplication", "only one instance of TGApplication allowed");
      return;
   }
 
   if (!gROOT)
      ::Fatal("TGApplication::TGApplication", "ROOT system not initialized");
 
   if (!gSystem)
      ::Fatal("TGApplication::TGApplication", "gSystem not initialized");
 
   gApplication = this;
   gROOT->SetApplication(this);
   gROOT->SetName(appClassName);
 
   GetOptions(argc, argv);
   if (argv && argv[0])
      gSystem->SetProgname(argv[0]);
 
   // Tell TSystem the TApplication has been created
   gSystem->NotifyApplicationCreated();
 
   LoadGraphicsLibs();
 
   if (fDisplay.IsNull()) gSystem->SetDisplay();
   fClient = new TGClient(fDisplay);
 
   if (fClient->IsZombie()) {
      Error("TGApplication", "cannot switch to batch mode, exiting...");
      gSystem->Exit(1);
   }
 
   // a GUI application is never run in batch mode
   gROOT->SetBatch(kFALSE);
 
   // Create the canvas colors early so they are allocated before
   // any color table expensive bitmaps get allocated in GUI routines (like
   // creation of XPM bitmaps).
   TColor::InitializeColors();
 
   // Set default screen factor (if not disabled in rc file)
   if (gEnv->GetValue("Canvas.UseScreenFactor", 1)) {
      Int_t  x, y;
      UInt_t w, h;
      if (gVirtualX) {
         gVirtualX->GetGeometry(-1, x, y, w, h);
         if (h > 0)
            gStyle->SetScreenFactor(0.001 * h);
      }
   }
 
   // Save current interpreter context
   gInterpreter->SaveContext();
   gInterpreter->SaveGlobalsContext();
 
   // to allow user to interact with TCanvas's under WIN32
   gROOT->SetLineHasBeenProcessed();
}
 
////////////////////////////////////////////////////////////////////////////////
/// TGApplication dtor.
 
TGApplication::~TGApplication()
{
   delete fClient;
}
 
////////////////////////////////////////////////////////////////////////////////
/// Load shared libs necessary for GUI.
 
void TGApplication::LoadGraphicsLibs()
{
   TString name;
   TString title1 = "ROOT interface to ";
   TString nativex, title;
#ifndef R__WIN32
   nativex = "x11";
   name    = "X11";
   title   = title1 + "X11";
#else
   nativex = "win32gdk";
   name    = "Win32gdk";
   title   = title1 + "Win32gdk";
#endif
 
   TString guiBackend(gEnv->GetValue("Gui.Backend", "native"));
   guiBackend.ToLower();
   if (guiBackend == "native") {
      guiBackend = nativex;
   } else {
      name   = guiBackend;
      title  = title1 + guiBackend;
   }
 
   TPluginHandler *h;
   if ((h = gROOT->GetPluginManager()->FindHandler("TVirtualX", guiBackend))) {
      if (h->LoadPlugin() == -1)
         return;
      gVirtualX = (TVirtualX *) h->ExecPlugin(2, name.Data(), title.Data());
   }
}
 
////////////////////////////////////////////////////////////////////////////////
/// Handle command line arguments. Arguments handled are removed from the
/// argument array. Currently only option "-display xserver" is considered.
 
void TGApplication::GetOptions(Int_t *argc, char **argv)
{
   if (!argc) return;
 
   int i, j;
   for (i = 0; i < *argc; i++) {
      if (argv[i] && !strcmp(argv[i], "-display")) {
         if (argv[i+1] && strlen(argv[i+1]) && argv[i+1][0] != '-') {
            fDisplay = argv[i+1];
            argv[i]   = nullptr;
            argv[i+1] = nullptr;
            i++;
         }
      }
   }
 
   j = 0;
   for (i = 0; i < *argc; i++) {
      if (argv[i]) {
         argv[j] = argv[i];
         j++;
      }
   }
 
   *argc = j;
}