[Radiance-general] getting pixel value at x,y

[Lars O. Grobe]

> The best/fastest solution for rectangular areas is pcompos piped into  
> pvalue and total, like so:
> 
> 	pcomb -o captured.pic \
> 		| pcompos -x ${box_width} -y ${box_height} - -${left} -${lower} \
> 		| pvalue -h -H -df | total -if3 -m
> 

Hm, ok, sorry, maybe this was obvious, if I only had not taken the -x -y
values as the new dimensions after scaling. So they actually crop the
box, which is just what I needed - thank you!!!

And one more question now - is there also a simple way to write pixel
values into a file like this? I wanted to put frames around some objects
in the image, but as I could not find a way to say AND in the
cal-expression pcomb expects, I do not know e.g. how to cut away the
inner part of a box.

TIA&CU Lars.