Sebastien,
I thought that the answer to your question was obvious.
Colors, line width, fill style, etc are a property
of each individual object. Lin/log scale is a property
of the pad containing the objects. It would not make much
sense to have in the same pad an histogram drawn with a log scale (x
and/or y) and another histogram with a linear scale.
In the original Hbook package, there was an option to set
a lin/log scale for an histogram. This was OK at a time
where histograms were "printed" on a line-printer one by one
in a serial way. It is not appropriate to a system supporting
multiple objects in the same container.
Rene Brun
On Wed, 24 Apr 2002, Sebastien Greder wrote:
> Hello Rene,
>
> Excuse me I couldn't reply directly last week about this.
> I don't agree with you, especially if you don't tell me why it was a
> mistake in PAW, I think that both features should be available.
> ===> Could you explain me why colors, titles, etc ... are then
> necessary histograms' properties ??
>
> cheers,
>
> sebastien.
>
>
> On Fri, 19 Apr 2002, Rene Brun wrote:
>
> > Hi Sebastien,
> >
> > The lin/log scale is not a property of the histogram. I know that
> > we had this feature in PAW and it was a mistake.
> > Lin/Log scale is a property of the pad.
>
> > You can toggle between lin/log scale after having drawn your histogram.
> > In the same way, you can change the object attributes after having drawn the
> > object Unlike in PAW where you had to repeat the complete set
> > of commands).
> >
> > Note that when drawing ntuples in a pad with a log x scale, TTree::Draw
> > will conveniently create a histogram with bins "linear in a log scale"
> >
> > Rene Brun
> >
> >
> >
> >
> > Sebastien Greder wrote:
> > >
> > > Hello Rooters,
> > >
> > > I was just wondering about TH1 objects ; usually when I want to plot
> > > an/several histo(s) and/or save it(them),the different steps look like:
> > >
> > > - create my histo
> > > - fill it
> > > - give some attributes settings (color, marker style and so on)
> > > - draw or histo->Write()
> > >
> > > If I want my histo(s) to have a log scale (x or y), I have to act on the
> > > corresponding pad through the SetLogX method. So this operation can only
> > > be done once the histo has been drawn or saved.
> > >
> > > Since I'm a lazy guy, I usually write some macros to plot/save several
> > > histos like :
> > >
> > > void Plot_ps(TH1* hist1, Char_t* title = "", Char_t* option = "",
> > > Bool_t logy = 0, Bool_t logx = 0, Bool_t fit = 0,
> > > Int_t stati = 111111, Bool_t wait = 0, etc .....)
> > > {
> > > TCanvas *c1 = (TCanvas*)gROOT->FindObject("c1");
> > > if (c1) {c1->Clear();}
> > > else {
> > > style();
> > > c1 = (TCanvas*)gROOT->FindObject("c1");
> > > }
> > >
> > > TPad* pad1 = new TPad("pad1","pad",0.03,0.03,0.98,0.98);
> > > pad1->Draw();
> > > if (logy) pad1->SetLogy(); if (logx) pad1->SetLogx();
> > >
> > > pad1->cd();
> > > hist1->SetFillColor(5);
> > > hist1->SetEverythingIwantToDoToHaveANiceHisto();
> > >
> > > if (fit) hist1->Fit("gaus");
> > > hist1->GetXaxis()->SetTitleSize(0.05);
> > > hist1->Draw(option);
> > >
> > > // l'histo est memorise
> > > c1->Update();
> > > }
> > >
> > > but it's not always a convenient situation.
> > > In fact there are a lot of things that can be set in before "validating"
> > > a histo (about ~40 "Set..." methods dealing with content,axis
> > > range,colors, etc ...) so why not SetLogX/Y ?
> > > It should be nice to have this possibility in TH1 or in TAxis (so that a
> > > histo->GetXAxis()->SetLogX() could be done).
> > >
> > > Or did I miss something and this operation is already available ??
> > >
> > > Cheers,
> > >
> > > sebastien.
> >
>
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