Hi Atila,
If you want to control the position of your TGaxis while rotating
your 2-d histogram, you can use the TExec mechanism.
See an example below
Rene Brun
//file cexec.C
// root > .x cexec.C
// when zooming on the x or y axis of the contour plot
// the projection will automatically be zoomed
TH2F *h2;
TPad *pad2;
TH1D *hp;
void cexec() {
h2 = new TH2F("h2","h2",30,-3,3,30,-3,3);
Double_t x,y;
for (Int_t i=0;i<10000;i++) {
gRandom->Rannor(x,y);
h2->Fill(x,y);
}
TCanvas *c1 = new TCanvas("c1","c1",10,10,800,500);
c1->Divide(2,1);
c1->cd(2);
pad2 = (TPad*)gPad;
c1->cd(1);
h2->Draw("cont");
TExec *ex = new TExec("ex","cproject()");
h2->GetListOfFunctions()->Add(ex);
hp = 0;
}
void cproject() {
TAxis *xaxis = h2->GetXaxis();
TAxis *yaxis = h2->GetYaxis();
Int_t ixmin = xaxis->GetFirst();
Int_t ixmax = xaxis->GetLast();
Int_t iymin = yaxis->GetFirst();
Int_t iymax = yaxis->GetLast();
if (hp) delete hp;
hp = h2->ProjectionX("hp",iymin,iymax);
hp->GetXaxis()->SetRange(ixmin,ixmax);
pad2->cd();
hp->Draw();
}
On Mon, 10 Jun 2002, Atila Alves Neves wrote:
> > When painting histograms, TGaxis is used to paint the histogram axis.
> > There is currently no way to specify the option "-" between TAxis
> > and TGaxis. You have to draw a TGaxis yourself.
>
> Ok. In that case, is there any way I can align a TGAxis when showing a
> TH2 (not a TH1, I made a mistake on the email title) in 3D mode, e.g.
> using option "surf1" or "lego"? I can position them on top of the regular
> x and y axes if the TH2 is shown in 2D, e.g. "col". As soon as you rotate
> the histogram in 3D mode... the drawn TGaxis just stays in place.
>
> >
> > Rene Brun
> >
> > On Sun, 9 Jun 2002, Atila Alves Neves wrote:
> >
> > > Hi. I was wondering if there was any way to access the TGaxis
> > > associated with a histogram axis? The thing is, I know how to make a
> > > TGaxis count backwards by passing the "-" option in, but how do I achieve
> > > the same effect with an axis belonging to a histogram?
> > > Thanks in advance,
> > >
> > > Atila Neves
> > >
> >
> >
>
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