[sane-devel] Passing all scanner usage through local saned

[thierryh at vivaldi.net]

Le 2024-05-11 17:16, Alexander Pevzner a écrit :
>> The eSCL and WSD devices provide their capabilities, so I don't see 
>> how an "IPP Scan" overlay would be better (the implementation why 
>> not).
>> I prefer the PIXMA or EPSONSCAN2 backends, which expose many more 
>> properties than eSCL or WSD.
> 
> Let me try to explain these things a little bit.
Thanks Alexander, that makes it clearer!

> 2. The daemon may initialize early, so when user application wants to 
> scan, everything is ready (currently, if there are many backends 
> enabled, initialization may take seconds).
 From my point of view, a scanner configuration module is missing, so as 
not to waste time on initialization.
Initialization should just be a readout of configured devices.

> The choice is between SANE's native protocol (used by saned and 
> sane-net backend) and standard-compliant scanning protocol (here we 
> have eSCL, WSD, TWAIN Direct and IPP-scan).
Once a configuration exists, sane-net is operational.


> So it is not actually correct to say that eSCL is limited in comparison 
> to the PIXMA protocol.
> 
> Cannon implementation of eSCL may be limited (and this is Canon's 
> decision to promote their proprietary protocol by limiting their 
> implementation of the standard eSCL), but these limitations are not 
> part of the eSCL specification by itself, and other hardware exposes 
> all its functionality to both proprietary protocol and to eSCL.
You're right, the problem isn't the protocol but the manufacturers, 
because this isn't unique to Canon.

Thierry