Printing canvas to png or jpg format - v5.16.00

ROOT
1

The behavior of the Print function for TCanvas appears to have changed between version 5.14.00 and 5.16.00. The entire canvas is no longer printed to the file, only a single Pad. I’ve attached a simple macro that creates the shows the problem (at least on my machine). I’m also attaching the output files.

Is this a new behavior of a bug? How can I print the entire canvas in jpg or png?

Thanks,
Chris

{
  TCanvas can("title","title",700,500);
  can.Divide(2,1);

  TH1I *hist = new TH1I("hist","hist",100,-50,50);

  TRandom rand;

  for(int i=0;i<1000;i++)
    hist->Fill(rand.Gaus()*10);

  can.cd(1);
  hist->Draw();
  can.cd(2);
  hist->Draw();

  can->Update();
  can->Print("can.jpg");
  can->Print("can.pdf");
}

can.pdf (15.1 KB)

can.jpg696×472 9.63 KB

2

I cannot reproduce this problem. On which system are you running?
Did you install ROOT yourself ?

Rene

3

I’m on a Windows XP system using the root_v5.16.00.win32.vc80.tar file. Info from the logon info:

Compiled on 29 June 2007 for win32 with thread support.

CINT/ROOT C/C++ Interpreter version 5.16.21, June 22, 2007

Chris

4

After playing with the example a little bit, I’ve noticed that it is only storing the active pad. If you change the active pad to the base canvas, i.e. can->cd(0), then you will have no problem.

Chris

5

Sorry, changing the active canvas does not consistently solve the problem. It seemed to work once and then it returned to it’s previous behavior.

Some other things we’ve noticed:

It works for pdf and gif; but fails for png and jpg.

After the macro runs (and the can->Print(“can.jpg”) command fails), you can run the same command at the ROOT prompt and it works as expected.

This is very strange behavior; I expect it is a bug.

Thanks,
Chris

6

You are right, this problem is visible on windows. On linux it is fine. It is a bug.
We will investigate. I’ll let you know.

7

Hi,
I’m working on it. Must be fixed asap.
Thanks for reporting it.

Regards, Valeriy