[sane-standard] Button handling

[Étienne Bersac]

Hi,

> SANE_TYPE_BUTTON is _completely_ different from the things we have
> discussed so far. The name is perhaps misleading, but it means an
> option that may be represented in the GUI of a frontend by a
> clickable button. Several backends provide such options, a quick
> grep through the source code of the backends shows that they are
> used for things like "swicth lamp on/off", "calbrate now" etc.

Ok, thanks, i misunderstood this. Off-topic, can you explain what
actually is calibration, and how often is that needed ?

> Cleanup of Sane1 options will not work. Why should anyone put much
> work into cleanup of old code, when you can expect that work on new
> code will start quite soon?

Whatever version you call it, (1.1 or 2.0), SANE needs a clean up in
option names and value variation in backends. That's doable in SANE 1, i
mean keeping the current SANE API (excluding Well-Known-Option by using
an external Well-Known options reference), keeping binary compatibility.

> As explained above, some scanners have "UI elements" like
> "function-wheel" that are so vague that you can't give a better
> option name.

Ok.

Is there an easy way to know if an option is for frontend itself or for
user ? For example, the plustek backend show 5 "button" option for my
CanoScan N1220U, and xsane shows an unsensitive checkbox for this
button, in a "buttons" frame. That's useless and even annoying for
end-users. Why is that option shown ? Is there a way for backend to
tell : this option is not for user. I think about SANE_CAP_HARD_SELECT.
Am i wrong ?

Thanks,
Étienne
-- 
Verso l'Alto !
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