Gilles Tran wrote:
> 
> In fact I realise that I was talking about a more general situation, where
> just a part of the image (like +sr0.536 +er0.7863 +sc0.456 +ec0.86) is
> rendered to be inserted at the corresponding spot in the entire image (when
> re-rendering a detail for instance). I'm under the impression that the exact
> position of the rendered zone isn't kept in the image file (but I could be
> wrong of course).

The offset (i.e. +sr/+sc different from 0) is stored in tga files and 
png files if PNG_READ_oFFs_SUPPORTED is defined (default is not AFAIK). 
  Of course paint program do not usually read them.

> The ability to re-render a selected zone on the top of an
> already rendered image (instead of replacing it) could be an interesting
> feature btw.

In fact i implemented such a feature for my planet renders 
(http://www-public.tu-bs.de:8080/~y0013390/pov/planets.html).  It is a 
lousy hack though.

I first render a black/white mask to define which pixels are rendered 
and which are taken from the old image and then render the scene with 
this mask as an additional parameter.  The patch only works with ppm 
output and tga for the mask IIRC and antialiasing is probably not 
handled correctly.

Christoph

-- 
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Last updated 2 Sep. 2003 _____./\/^>_*_<^\/\.______

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