embedding ROOT

Pasha Murat (murat@cdfsga.fnal.gov)
Thu, 25 Sep 1997 23:01:32 -0500

This is kind of issue which people will never agree upon...
I'm trying to write a prototype of event display code
based on ROOT graphics classes. By design this shoudn't be a
standalone application, instead it should be called by another routine:
I need main to be loaded statically because otherwise there is no
way to debug the whole system. This is nothing but embedding ROOT
into another application. Having started from test/hworld.cxx
I've been trying to make the code reentrant: after the event display
routine is executed, all the windows should be closed. The example below
bombs. I guess that this is happening because TCanvas::Close() does
much more than just closing the window on the screen.

Is it possible to modify the example below so it would close a canvas after
the first call to TApplication::Run() and reopen it at the second call?

I'd appreciate any hints on this subject.
Thanks, Pasha.
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#include "TROOT.h"
#include "TApplication.h"
#include "TCanvas.h"
#include "TLine.h"
#include "TPaveLabel.h"

extern void InitGui();
VoidFuncPtr_t initfuncs[] = { InitGui, 0 };
int Error;
TROOT root("hello","Hello World", initfuncs);
TApplication* theApp;

main(int argc, char **argv) {
TApplication theApp("App", &argc, argv);
TCanvas c("c", "The Hello Canvas", 400, 400);
c.Update();
theApp.Run(kTRUE);
c.Close();
c.Update();
theApp.Run(kTRUE);
}
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