Ciao,

This directory contains the source code in files

canvsave.h
canvsave.cxx
histaction.h
histaction.cxx

the makefile

Makefile

and

hist4_5.root
hist6_8.root

each including a set of one-dimensional histogrammes with real TOF data
from the last beam test in GSI (December 1998), then

LinkDef.h

necessary for the ROOT CINT and finally

rootlogon.C

which is executed when ROOT starts.

The program itself is a demo version of a control panel which allows to perform
a few actions with one-dimensional histogrammes (in ROOT terms objects of
class TH1F). So this can be regarded as a small presentation how nice and easy
will be the work with the HADES analysis stuff in the future when the ROOT GUI
classes will be introduced to the game.

To create the shared library "libHistViewer.so" one has to type from the OS
prompt string the following command:

(g)make

The shared library "libHistViewer" will be created.
Then start ROOT and the shared library will be
loaded, and an object of the class HistAction will be created resulting in
appearance on the screen the window "Histogram Viewer".

A few comments to conclude this introduction.

1. Right now the program provides the full functionality only for
   one-dimensional histogrammes (class TH1F). Two-dimensional histogrammes
   (class TH2F) can be read from a file or imported from memory, drawn
   in the main canvas and saved as a picture but it is not possible at
   the moment to apply to them the functionality of the "Scan" panel.

2. There is an internal container which stores the histogrammes visible
   for the program. The capacity of this container is now fixed to 1000
   histogrammes.

3. To put the histogrammes to the container from a ROOT file (*.root) one has
   to simply doubly click on the icon with that file in the "File Manager"
   window.

4. It is not possible right now to import a histo from the memory by means
   of clicking some button somewhere on the panel, but nevertheless this
   feature is realized in the class HistAction. So, to import
   a histogram one has to type a command from the prompt string of
   the interpreter.

   Example:

Assuming that the panel was opened by rootlogon.C and the name of the pointer
to the class HistAction is 'gui',

   root[0] Float_t x,y;
   root[1] hist = new TH1F("GAUS","My Histo",100,-4.,4.);
   root[2] for(Int_t i=0; i<10000; i++) {gRandom->Rannor(x,y); hist->Fill(x);}
   root[3] gui->importHist(hist->GetName());

5. If a user doubly clicks on an icon with a file which can be viewed with
   a viewer like gv or xv, then that file is loaded to the viewer. This
   feature allows to have a look at the saved picture without leaving ROOT
   or typing some commands.

Try to play with this stuff.


Dmitry Vasiliev
08.06.99
LNS, Catania