[sane-devel] Canon N 650U Calibration step...

[Henning Meier-Geinitz]

Hi,

On Thu, Mar 06, 2003 at 05:19:29PM +1030, Pierre Dumuid wrote:
> I can see that sane has a back-end and a front end, that makes all 
> scanners very modular and have the same basic interface, but is it 
> possible for extra special requests such as calibration to be requested 
> from the client to the back-end to perform calibration (i.e. we could 
> then calibrate only once).

The vackend provides options that can be set by the frontends and/or
user. All the settingy you see (e.g. scan mode, geometry) are backend
options.

So in this case, the backend would provide a button option. When the
button is pressed, the action is done (e.g. calibrate). For an example
of such a button option, see the test backend (xsane test).

> Also does the backend provide any functionality for the frontend to
> query the backend to see what extra functionality the scanner
> provides?

No problem. Just use a "string list" option. The user can decide what
to do with it.

>   2. the scanner has a calibration procedure with a pop-up warning of
>      "Please Close Lid while calibration is being performed"

That isn't supported by the current standard.

> (along with each property, there may be a description when the mouse is 
> dragged over the button)

Each SANE option has a description which may be displayed as tool tips.

See the test backend for which types of options SANE provides.

Bye,
  Henning