Re: [ROOT] canvas created but not drawn ...

From: Jacek M. Holeczek (holeczek@us.edu.pl)
Date: Fri Apr 11 2003 - 19:12:44 MEST


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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