Re: Zooming problem with TGraph

From: Rene Brun <>
Date: Sat, 29 Apr 2006 19:01:42 +0200 (MEST)

In attachement, see a new version of your script that will work correctly with unzooming. It uses a function DrawFrame that is a copy of the updated function TPad::DrawFrame now in CVS.

Rene Brun

On Sat, 29
Apr 2006, Marco Calviani wrote:

> Hi Rene,
> thanks for your reply.
> 2006/4/29, Rene Brun <>:
>> The zoom precision corresponds to the number of bins along x or y.
>> In case of log scales and a big range (in your case 1e-2 to 1e6)
>> the current algorithm may fail if the number of bins is too small.
>> I habve modified your program to be able to zoom more deeply in
>> your graph. see below.
> i've done how you told me but i'm encountering two problems:
> 1) When i zoom on the Y axis, the minimum does not longer stay
> blocked, but unfortunately when i try to unzoom the following error
> appears:
> Error in <THistPainter::PaintInit>: log scale is requested but maximum
> is less or equal 0 (0.000000)
> 2) Along the X axis the correct zooming process is allowed only if the
> lower limit is set to 5-6. If lower than this the minimum is always
> 10e-2.
> Regards,
> MC

Received on Sat Apr 29 2006 - 19:01:47 MEST

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