[sane-devel] SANE standard details

[Peter Fales]

> How can you set SANE_INFO_RELOAD_OPTIONS during the scan? You can only do this
> in sane_control_option as far as I see.

You're right.  I wasn't clear about that.  What I actually do is set a flag
so that the next time sane_control_option is called, it will set
SANE_INFO_RELOAD_OPTIONS no matter which option is requested.

> > - If the first thing I do after the scan is click on the image number slider,
> >   xscanimage aborts with a memory fault
> 
> Oops. It probably trys to access the option_descriptor. Did you malloc a new
> one? The option_descriptor must stay valid until sane_close (or a reload).

No, the option descriptors are all in a statically allocated array.

> > - If I click on something else like a checkbox, then the slider range also
> >   gets updated.
> 
> Maybe the checkbox set "SANE_INFO_RELOAD_OPTIONS"?

Probably. Even if it wouldn't normally do it, the flag I set during the
scan would force it in this case.

> Maybe it makes sense to reload all options after the scan automatically. Does
> xsane do this?

I don't know how hard that would be to implement, but I think it might
be a good idea.   While I can't think of any real-life examples
offhand, it seems quite possible that there are other reasons why an 
option might change during a scan.

Pete Fales