Re: [ROOT] Questions about co-ordinate systems

From: Rene Brun (Rene.Brun@cern.ch)
Date: Mon Mar 08 2004 - 09:01:31 MET


Hi,

> Stilianos Kesisoglou wrote:
> 
> Hi,
> 
>     I have a couple of questions about the co-ordinate systems used on ROOT.
> 
>     a)    Is there any "generic" way to move from the one system to the other?

You can convert from pad coordinates to pixels and vice versa with
 TPad::XtoPixel, XtoAbsPixel, PixeltoX, etc
You can convert from NDC to Pixels and back with:
 TPad::UtoPixel, UtoAbsPixel, etc

You can convert from user coordinates (linear or log scale) to pad coordinates
with TPad::XtoPad, PadtoX, etc
XtoPad is a noop if linear scale

> 
>     b)    Do all objects that can be drawn understand all the co-ordinate
> systems?

All basic primitives can be drawn in user coordinates.
Most of them can be drawn in NDC (via the DrawNDC function or SetNDC bit)

Since version 3.10/02, all basic primitives can be drawn in lin or log scales
Before this version, only TH1, TF1 and TGraph could be drawn in log scale.

Rene Brun

> 
>     Thanks!
> 
> Stelios.



This archive was generated by hypermail 2b29 : Sun Jan 02 2005 - 05:50:06 MET