[sane-devel] CanoScan 3200F: brief status update

[Lauri Pirttiaho]

To all who are eagerly waiting the CS3200F backend.

Not very much has happened since my last report.
The reasons for that are many but one of the most
important is that my original approach was not
robust enough to allow integration of the actual
scanner driver. Therefore I spent about two weeks
in restructuring the backend so that various features
can be modularly added in. Now the structure is such
that the actual API functions do very little else
that forwarding the requests to actual functionality
implementing modules.

So, the structure now is such that the option handling
is taken care of by the options module which statically
contains all option descriptors. When the descriptors
are requested, the returned descriptors are chosen 
based on the state of the particular device. The state
of the device is encapsulated into another module
dedicated for data operations. That contains now
the current state of all options and parameters
for the device and will also contain the device 
specific calibration data. I have not yet decided
how to carry over the semi persistent calibration
data from session to another (maybe there is a
standard way to do this, I have to look at other
drivers how they do it) but at first I won't save
any calibration data.

The actual scaning is done by the scanning module
which takes its parameters from the data module and
uses two layers of drivers to access the scanner: one
layer for logical macro operations like move, home,
calibrate etc. and another for low level USB access
built on top of the sanei_usb library.

So far I have succesfully booted the scanner and 
implemented the lamp control. The next, currently
being worked on, is the motion control and then
I will implement the AFE and shading calibration.
Then the last step will be the actual scanning.
All this will be first implemented for reflective
mode only and then later will come time fo the
transparency adapter (film scanning).

With best regards,

Lauri Pirttiaho
Oulu
Finland


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