User coordinates from TPad

ROOT
1

Hi everybody,

I found a difference in ROOT when running CINT or compiled code.

What I want to do is to plot a box over a certain range of an histogram.
I need the box to be defined between x1 and x2 (fixed) and to get y1 and y2 from the histogram frame.
If I create the histogram, the canvas and the box using CINT, it works fine, as you can se from the attachment ‘testPadCoordCINT.gif’;
while if I run the code from file

$ root -l testPadCoord.cc

or I try to compile it

$ root -l testPadCoord.cc+

I get no band (better, the box has y1=0 and y2=1) as you can see from the attachment ‘testPadCoord.gif’.

I also attached a file with a running example (‘testPadCoord.cc’).

Is this a bug?

Maurizio

ps: I am using ROOTv5.25.04 compiled from source on linuxx8664gcc (gcc 4.4.1)
also tried on a macosx64 with gcc 4.4.1
testPadCoord.cpp (775 Bytes)



2

put:

gPad->Update();

after:

h2->Draw("same,e");
3

Thanks Couet,

it now works.

Can you tell me what happens to the pad when I plot an object with “same” option? And why it was OK using CINT?

4

You draw the box according to the Pad coordinates. But the Pad coordinates are valid only once the histogram has been painted. The line I asked you to had forces the painting. For more details see:
root.cern.ch/drupal/content/graphics-pad