[ROOT] bug in gPad->PixeltoY()?

From: Dirk Dodt (dodt@mail.desy.de)
Date: Tue Jun 22 2004 - 18:41:29 MEST

I have the feeling the TPad::PixeltoX Method Or Rather the underlying 
method whichs sets the needed Coefficients might be buggy.

The mistake (if any) can sometimes(!) be corrected by using 

Maybe I have not fully understand everything concerning the different 
coordinate systems, but if someone else is having similar problems it 
might be worth looking into it. (For my own case I already have found a 

For Completeness:
I'm using a TRootEmbeddedCanvas in Root 3.10_03 (Suse 7.3/=Desy linux 4) 
inside a QT Gui to Display some Detector Information.

In order to do a Zoom into the Detector, I Connected the 
ProcessedEvent(Int_t,Int_t,Int_t,TObject*) Slot with my code, that uses 
PixeltoX and PixeltoY to transform the x,y[pixel] provided by the signal 
into user coordinates and set a new ...->Range(x1,y1,x2,y2) for the Pad.

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