[sane-devel] RFC: SANE2 and previews

[Major A]

Another suggestion for SANE2:

In sane_control_option(), the info passed back in *i should allow the
backend to ask for the preview to become invalid. I think this would
be useful for backends which can change something fundamental (like
exposure) that changes the way the image is scanned. This is not
essential, it would just make the interface more idiot-proof: a
frontend could mark the preview as invalid (with a red line through it
or similar -- not by deleting the preview!) to indicate that the image
to be scanned will be different from the one in the preview.

Therefore, how about SANE_INFO_INVALIDATE_PREVIEW ?

We could also go for a more elaborate approach which allows the
backend to request corrections to the preview. If, for example, red
channel exposure is increased by a factor of 1.2, it would be possible
to correct the preview without scanning a new one. (Note: this could
be the exposure time of the scanner, which is independent of the
LUTs.) Any suggestions?

  Andras

===========================================================================
Major Andras
    e-mail: andras at users.sourceforge.net
    www:    http://andras.webhop.org/
===========================================================================