Re: histograms embedded in TCanvas

From: Adrian Sevcenco <Adrian.Sevcenco_at_cern.ch>
Date: Tue, 14 Feb 2012 09:03:50 +0200

On 02/13/12 23:25, Timur Pocheptsov wrote:
> TCanvas' ctor you are using, is not reading anything from file.
>
> void cnv() { TFile *f = new TFile("canvas.root", "read"); TCanvas *c
> = (TCanvas *)f->Get("a");

Many thanks Timur! Everything is ok now!

Adrian

> if (c && c->GetListOfPrimitives()) {
> c->GetListOfPrimitives()->Print(); } }
>
> I have a root file with TCanvas inside, canvas has a name "a", its
> list of primitives contains one object (TH1F, with name "aa"), output
> is:
>
> root [0] .x cnv.C Collection name='TList', class='TList', size=1
> TH1.Print Name =h aa, Entries= 100000, Total sum= 100000.
>
> I think, if you want to use objects from TCanvas, you'll also have to
> do something about objects' lifetime later.
>
> ________________________________________ From: Adrian Sevcenco Sent:
> 13 February 2012 21:25 To: Timur Pocheptsov; roottalk_at_root.cern.ch
> Subject: Re: [ROOT] histograms embedded in TCanvas
>
> On 02/13/12 21:47, Timur Pocheptsov wrote:

>> Hi Adrian.

> Hi Timur!!
>

>> Read your canvas and ask it for a list of primitives?
>> 
>> TCanvas * c = (TCanvas *)f->Get(.....); if (c) { .... TList
>> *primitives = c->GetListOfPrimitives();

> well i have this code :
>
> TFile *f = new TFile("spectra_kaon_minus.root"); if (!f) return;
>
> f->ls();
>
> TCanvas *c = new TCanvas ("f:cCanvas_kaon_minus"); TList *p =
> c->GetListOfPrimitives(); p->Print();
>
> and this is the output
>
> root [0] Processing test.C... TFile**
> spectra_kaon_minus.root TFile* spectra_kaon_minus.root KEY:
> TCanvas cCanvas_kaon_minus;1 Collection name='TList', class='TList',
> size=0
>
> is there other way to investigate contents of the canvas?
>
> Большое спасибо :), Adrian
>
>

>> 
>> ///iterate on this list.
>> 
>> } ________________________________________ From:
>> owner-roottalk_at_root.cern.ch [owner-roottalk_at_root.cern.ch] on behalf
>> of Adrian Sevcenco [Adrian.Sevcenco_at_cern.ch] Sent: 13 February 2012
>> 20:24 To: roottalk_at_root.cern.ch Subject: [ROOT] histograms embedded
>> in TCanvas
>> 
>> Hi! I have an root file that have an TCanvas saved inside. Inside
>> in that TCanvas somehow there are a few histograms. How can i list
>> and handle (access) those histograms?
>> 
>> Thank you, Adrian

>
>

-- 
----------------------------------------------
Adrian Sevcenco                              |
Institute of Space Sciences - ISS, Romania   |
adrian.sevcenco at {cern.ch,spacescience.ro} |
----------------------------------------------







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Received on Tue Feb 14 2012 - 08:03:58 CET