[sane-devel] epsonds backend ADF size with ES-50

Sean Greenslade sean at seangreenslade.com
Sun Sep 4 07:47:41 BST 2022

On Thu, Sep 01, 2022 at 03:51:00PM -0700, Ralph Little wrote:
> Typically, SANE options are adjusted by amendments to others.
> So if you change the resolution or source, other options and/or their
> respective limits are amended accordingly. So, for example, if you change
> the res to 600dpi, then upper limit on height would change to the lower
> limit and if the currently selected value for height exceeded that limit it
> would be adjusted downward.
> There are specific flags in the option definitions to indicate this to the
> frontend as well. So if an option is changed that affects other options, a
> flag is set to information the frontend to re-acquire values and attributes
> of the other options to get any changes.

Thanks for the hints. I started digging in to the epsonds backend and it
was pretty easy to graft on an adjustment to the ADF scan area when the
DPI value is changed by the frontend. I've submitted a merge request
with my code changes:


It would still be nice to know if the relationship between AREA / AMAX
and DPI can be queried out of some / all epson scanner models. My fix
baked in the assumption that the AMAX size only works on the smallest
DPI setting.


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