On Mon, 5 Aug 2002, Rene Brun wrote: > Could you send me evidence that the option (cont List) returning > a list of TGraphs does not work (C++ macro and a Root file)? Hi Rene, sorry for the late answer, but my delay was due to some changement of behaviour I have observed as I was preparing the macro and the root file for you to check. You can find the macro and the root file under /afs/cern.ch/user/g/gbruno/public/For_Rene/ Part of the problems (unpredictable behaviour) have disappeared as soon as I got rid of a library that I used to load at the beginning of the macro, but that I was not actually using to make that particular contour plot. This library had been compiled separately with the compiler used by the reconstruction program ORCA of CMS (gcc 2.95.2). I have not understood yet why this caused problems but I guess it could be linked to some conflict since in the library I was using the class TObjArray. However after removing the load of this library I have still error messages. Actually I have now realized (after restarting root from scratch), that the error occurs at different lines according to the past of the root session. The last error I get is Error: illegal pointer to class object contours 0x0 219 FILE:Rene.C LINE:95 Before restarting root, this line was not giving any problem. Instead I could not get access to contour 9 , the last of the 10 I set. The other contours seemed to be ok. The error was Error: illegal pointer to class object contours 0x0 219 FILE:Rene.C LINE:101 *** Interpreter error recovered *** I hope you will be able to help me cheers Giacomo > > Rene Brun > > On Mon, 5 Aug 2002, Giacomo Bruno wrote: > > > > > Hi > > I would like to draw a 2-d histogram in contour format showing the levels > > with lines of different colours. I get the lines as expected, but then I > > would also like to draw a legend. > > To this aim I need to retrieve in some way the colours id > > of the lines. On the user's guide 3.02 at page 42 it is explained how to > > access the TGraph objects that are created when drawing a contour plot, however when I > > tried it everything happened (sometimes crashes, sometimes wrong results and > > almost always running the same code gave different results). I was then obliged to > > guess the colours and set them by hand. Does anyone have an idea on how to > > solve this problem? > > Thanks in advance > > > > cheers > > Giacomo > > > > > > > > ----------------------------------------- > > | Giacomo BRUNO | > > | | > > | CERN | > > | EP Division | > > | | > > | mail: 40-2-B20 | > > | C.E.R.N. | > > | CH - 1211 Geneva 23 | > > | Switzerland | > > | e-mail: Giacomo.Bruno@cern.ch | > > | phone: +41 22 76 71624 | > > ----------------------------------------- > > > > > > > > ----------------------------------------- | Giacomo BRUNO | | | | CERN | | EP Division | | | | mail: 40-2-B20 | | C.E.R.N. | | CH - 1211 Geneva 23 | | Switzerland | | e-mail: Giacomo.Bruno@cern.ch | | phone: +41 22 76 71624 | -----------------------------------------
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