Jacek,
A small example of main program producing a canvas.
This requires a TApplication, but not a TApplication::Run
Rene Brun
#include "TApplication.h"
#include "TCanvas.h"
#include "TPaveLabel.h"
int main(int argc, char **argv)
{
TApplication theApp("App", &argc, argv);
TCanvas *c = new TCanvas("c", "The Hello Canvas", 400, 400);
TPaveLabel *hello = new TPaveLabel(0.2,0.4,0.8,0.6,"Hello World");
hello->Draw();
c->Update();
getchar();
return 0;
}
On Fri, 11 Apr 2003,
Jacek M. Holeczek wrote:
> Many thanks for help,
>
> > I have the impression that you are running in batch mode. This is the
> > case when you do not define a TApplication object or if explictly
> > you call gROOT->SetBatch(kTRUE); Please check.
>
> I do not create "TApplication" (and I do not say "gROOT->SetBatch(kTRUE)").
> Earlier today I had the idea to try "gROOT->SetBatch(kFALSE)" just before
> making the new TCanvas, but it didn't help.
>
> Can I somehow convince TROOT to draw my TCanvas without creating the
> "TApplication" ?
>
> > About your point with c->Draw, you should not do:
> > c->Draw(); c->Update();
> > but
> > c->Modified(); c->Update();
>
> This code is more than one year old (was running fine with 3.02, if I
> remember well). It redraws the canvas using new contents of histograms
> every 10 seconds. The sequence "c->Draw(); c->Update();" was found
> EXPERIMENTALLY by me. No other sequence was behaving properly (including
> "c->Modified(); c->Update();"). It may well be that now I can change it.
> Well, I could make some tests ... as soon as I get the canvas drawn.
>
> Thanks in advance,
> Jacek.
>
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