Re: [ROOT] TImage, AfterImage problem

From: Fons Rademakers (Fons.Rademakers@cern.ch)
Date: Thu Jun 19 2003 - 12:53:08 MEST


Hi Reiner,

 I've made the changes and on
ftp://root.cern.ch/root/libAfterImage.tar.gz you can find the new
updated tar file.

Cheers, Fons.


On Fri, 2003-06-13 at 14:04, Reiner Rohlfs wrote:
> Hi Michal,
> 
> I think this is a libAfterImage problem.  The library has a division by 0.
> 
> In the file transform.c the line 1820 and 1821 :
> 
> 				multipliers[y][x] =
> (double)(palette->channels[y][x+1] - palette->channels[y][x])/
> 				                 	       
> (points[x+1]-points[x]);
> 
> has to be replaces by 
> 
>             if (points[x+1] == points[x])
>                multipliers[y][x] = 1;
>             else
> 				   multipliers[y][x] =
> (double)(palette->channels[y][x+1] - palette->channels[y][x])/
> 				                 	       
> (points[x+1]-points[x]);
> 
> It is not important to which multipliers[y][x] is assigned to. If points[x+1]
> == points[x] than multipliers[y][x] will by multiplied by 0 anyhow, as fas as I
> understand the code. But it should not NaN.
> 
> With this lines your image looks OK for me. 
> 
> Rene, Fons can you also make these changes in the libAfterImage library ROOT
> supports.
> 
> Cheers Reiner.
> 
> 
> 
> On  6-Jun-03 at 23:09, Michal Lijowski (michal@cvu.wustl.edu) wrote:
> > 
> >   I have one more problem with TImage or maybe AfterImage.
> >   When I run the attached code I get two canvas but on the bottom
> >   of the image there is white band along part of the bottom of
> >   the image. The same case is for color paletter. I try to find out
> >   where the problem is by running asvector program located in
> >   libAfterImage/apps directory. But the resultant image has black
> >   band on the bottom along full width. This band does not appear 
> >   on the jpeg version of this image. I sent email to author of 
> >   this software and he advised to grab the CVS version. So I did. 
> >   But after correcting a couple compilation errors, the effect is 
> >   the same. The resultant image from asvector program has black band
> >   on the bottom.
> > 
> >   I am running ROOT 3.5/5 under RH Linux 9.0 with gcc 3.2.2.
> > 
> >   Thank you for the attention.
> > 
> >    Michal 
> >   
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