[sane-devel] Planar & Chunky

Frank Zago fzago at austin.rr.com
Sat Sep 20 10:29:40 BST 2003

Guy Brooker wrote:
> A front end question !
> As far as I understand from the SANE spec, a backend may send colour image
> data as either an R, G & B sample per pixel, what TWAIN refers to as chunky,
> or as three separate images, one of R, one of G and one of B, what TWAIN
> refers to as planar.
> Is there any way of forcing a backend to go one way or another ?

No. It depends on how the backend has been coded; which itself depends on how 
the scanner returns the data.

> And secondly, is there any way of determining if the data will be planar or
> chunky before calling sane_start() ?

I don't think so. It seems that all recent backends do only one pass, so you 
might get away with not coding for 3 passes backends.


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