Re: Problems with TH2F->Draw("col")
Rene Brun (Rene.Brun@cern.ch)
Fri, 08 Jan 1999 15:56:32 +0100
Thomi Walter wrote:
>
> Hi everybody!
>
> On my system, the option "col" doesn't function at all.
> (linux, libc5, root 2.0.13)
>
> Here is a interactive root-session as a example:
>
> root [0] TH2F myHH("Tt1", "TT2", 8, 0., 32., 32, 0., 16.);
> root [1] myHH->SetBinContent(34,10.);
> // the following options are functioning correctly!
> root [2] myHH->Draw("lego");
> root [2] myHH->Draw("lego1");
> root [2] myHH->Draw("lego2");
> root [2] myHH->Draw("lego3");
> root [2] myHH->Draw("surf");
> root [2] myHH->Draw("surf1");
> root [2] myHH->Draw("surf2");
> root [2] myHH->Draw("surf3");
> root [2] myHH->Draw("surf4");
>
> // with the following options only a empty hisogram is drawn!
> root [3] myHH->Draw("col");
> root [3] myHH->Draw("cont");
> root [3] myHH->Draw("cont1");
>
> What am I doing wrong?
>
> Many thanks in advance!
>
> Thomas Walter
When you use TH1::SetBinContent, the number of entries in the histogram
is not changed (only TH1::Fill increments).
The 3-d Paint functions do not check if the number of entries = 0,
but this check is in the 2-d Paint functions.
If you add the following statement after myHH->SetBinContent(34,10);
myHH->SetEntries(1);
then the 2-d drawing will work as expected.
I will modify the code to remove the check on the number of entries
in the 2-d drawing functions.
Rene Brun