Re: TAxis::SetLimits()...

From: Volker Boerchers (boercher@physik.uni-bremen.de)
Date: Tue Nov 09 1999 - 17:07:32 MET


Hi Rene,

> As you have found, the command line equivalent of a zoom with the mouse
> is
>   axis->SetRange(firstbin, lastbin);
> The parameters are integers and are the first and last bin that you want
> to see. I CANNOT implement SetRange with axis values. Many reasons:
>  - an histogram is defined with fix size or variable size bins.
>  - The bin contents have already been set. cannot rebin to the new
>    values without refilling.
>  - In these conditions, which convention for the cut? low edge of
>    the bin corresponding to the cut ?, center, upper edge ? What about
>    variable bin size histograms?
>  - the system must work for all dimensions, not only 1-d.
>  - If I authorize the cut on axis values, I get immediatly the
>    complaints from people who will see a different value selected by
>    the system (eg low edge of the bin corresponding to xmin, upper
>    edge of the bin corresponding to xmax).  In this case, I will
>    immediatly get "suggestions for improvement" of the style: if
>    the cut is closer to the low edge of the bin, take the low
>    edge, otherwise the upper edge, etc.

sorry for misleading.

This is not what I had in mind. Perhaps the word `zoom' fits much
better than Set...Range since I only want a different *view* on a
function or histogram, not a change of the histogram. The suggested
SetAxisRange() function should do nothing else than what you can do
with the mouse: zoom in or out. (And I don't think a histogram or
function must get computed anew for this.)

Then, if only the view/display is concerned a `cut' would only mean that
the function/histogram is `invisible' in the cutted area, allowing for a
cut anywhere in between a bin. I can't see why such thing should be
necessarily limited to 1-d.

Regards,
  Volker

--_----_----_----_----_----_----_----_----_----_----_----_----_----_--
Volker B"orchers, Uni Bremen, NW1, Raum 03160, Tel. +49-421-218-4522
 mailto:boercher@physik.uni-bremen.de
 http://hix.physik.uni-bremen.de/~boercher



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