[sane-devel] Standard option definitions

[Dave Close]

Our practice is to provide a standard user interface for all of our
scanners. These UI programs then call upon the SANE backends as needed.
Of course, they need to be able to understand the options for each of
the backends so they can translate the user's choices. But it appears
that there is little standardization in the way various backends define
and use even the standard options defined in include/sane/saneopts.h.
I'd appreciate any clarification which can be offered.

* SANE_DESC_SCAN_MODE 
  Selects the scan mode (e.g., lineart,monochrome, or color).

  Is there any standard list of modes from which to choose? When two
  backends use different string values for what appears to be the same
  choice, it makes the UI awkward at the least.

* SANE_DESC_SCAN_SPEED 
  Determines the speed at which the scan proceeds.

  Is there any standard unit of measure for this variable? Some backends
  seem to assign strings, others assign numeric values. The meaning of
  the numbers is not consistent and even the strings are different from
  one backend to another.

* SANE_DESC_CAL_LAMP_DEN 
  Define lamp density for calibration
* SANE_DESC_SCAN_LAMP_DEN 
  Define lamp density for scan
* SANE_DESC_SELECT_LAMP_DENSITY 
  Enable selection of lamp density

  These appear to be unique to the UMAX backend. Should I understand
  that "density" is, in some sense, equivalent to "intensity"?

I can understand that SANE does not want to preclude innovation in the
hardward realm by limiting the choices. But I do think we could be a
little more consistent in the use of these options. At the least, SANE
should specify if a standard option should be a string, a number, or a
boolean. If there is a need for more than one type, they should be
different options.
-- 
Dave Close                    Dreamworks SKG, Animation Technology
+1 818 695 6962               Glendale California 91201-3007
dclose at anim.dreamworks.com    http://www.dreamworks.com/