Exclusion Area in 2d

Hi!

>From some calculation I've two dataset of x,y,z values. Now
set 1 defines an exclusion area of set 2 and I want to draw those both in one plot. I've valid TGraph2D ojects and I try the following:

   gr1 = TGraph2D("excl.dta");
   gr2 = TGraph2D("data.dta");

   // Get the first contour of gr2 and store it's TGraph object in gr2c    Double_t levels[1]; levels[0] = 100.;    gr2->GetHistogram()->SetContour(1, levels);    gr2->Draw("cont,list");
   c1->Update();
   TObjArray *contours =

      (TObjArray*)gROOT->GetListOfSpecials()->FindObject("contours");
   TList *lcontour1 = (TList*)contours->At(0);
   TGraph *gc2 = (TGraph*)lcontour1->First();

This is nearly straight from thre root manuals and I indeed get the 100% countour in question as a TGraph-Object. All is well. This graph is nearly a rectangle. Now I try to superimpose both:

   c2 = new TCanvas("c2","canvas",200,10,xdim,ydim);

   gr1->Draw("cont1");
   gc2->Draw("l,same");

Unfortunately gc2 fills "the wrong side" of the rectangle. According to the manual I should use something like

   gc2->SetLineWidth(-9901);

to fill the other side, ie. the outer frame. But this does not really work out.

What am I doing wrong here? Or is the problme, that my exclusion area is a closed curve? (I use a construct like the above in other context where it works but the exclusion area is no closed curve.)

-- 

Kind regards,                /                 War is Peace.
                            |            Freedom is Slavery.
Alexander Wagner            |         Ignorance is Strength.
                            |
                            | Theory     : G. Orwell, "1984"
                           /  In practice:   USA, since 2001