Re: Histogram title

From: Rene Brun (Rene.Brun@cern.ch)
Date: Fri Mar 07 1997 - 08:50:54 MET


Chris Green wrote:
> 
> >
> > > Finally, what's the easiest way of shading in an area on a histogram > in a specific colour / shading pattern?
> > >
> >
> > Click on the histogram with the rigth mouse button and select
> > the item "SetFillAttributes". This will display a panel with
> > colors, fill styles,etc.
> > In a macro, you can do:
> >   h->SetFillColor(color);
> >   h->SetFillStyle(3001);
> 
> Thanks for all that, however for the last question what I actually want to
> do is shade in an arbitrary area (defined by points) which isn't defined
> on the histogram. ie take the example where I have an exclusion region for
> a search in 2D parameter space, and also want to shade off kinematically
> excluded regions without altering the contents of the histogram. In
> summary, I want to make a primitive filled area with a different shading
> style to the rest of the histogram.

To fill an arbitrary fill area on the existing picture, you can create
a TGraph object 
    gr = new TGraph(n,x,y)
where x and y are the n coordinates of the fill area.
    gr->SetFillStyle(3002); // or any other fill style
    gr->SetFillColor(2);    // or any other color
    gr->Draw("F");          // draw graph with fill area option

In version 1.0, I have added the possibility to draw subranges
of 1-d, 2-D histograms. To draw a subrange of an histogram with
a color and style, you will 
  - draw the original full picture
  - select the histogram range
  - draw again with option same

Rene Brun



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