[sane-devel] plustek:libusb bugs on canon canoscan n1220U

[m. allan noah]

On Wed, 9 Aug 2006, Étienne Bersac wrote:

> Hello,
>
>> scanimage -L reports:
>> device `plustek:libusb:003:003' is a Canon N1220U USB flatbed scanner
>
> User should have
>
>        bersace at celebrad:~$ scanimage -L
>        device `plustek:libusb:002:002' is a Canon CanoScan N1220U flatbed scanner
>        					   ^^^^^^^^      ^^^
>
> The USB in "USB flatbed scanner" is very annoying since that make type
> parsing hard if an app want to show an icon representing the type of the
> device. I guess an enum should be better than string.

1. CanoScan is missing? it is not be possible to have the scanner report 
what is printed on its outside, only the inside :)

2. USB is added? yes- the type strings are defined on page 18 of the sane 
spec, and it should only be 'flatbed scanner'

>
>> SANE_TYPE_OPTION does not exist
>
> Sorry, i meant SANE_TYPE_{BOOL,INT,FIXED,STRING}.
>
> The 5 options "button" have SANE_TYPE_BOOL as type (in
> SANE_Option_Descriptor struct). That should be SANE_TYPE_BUTTON.
>

3. button type is bool? read the sane standard- SANE_TYPE_BUTTON has no 
value! how can the backend signal a button has been pressed with no value? 
SANE_TYPE_BUTTON is a poorly named choice, but it is used to have the 
frontend 'set' the backend to do something.

a frontend writer who wishes to work with buttons should be prepared for 
bool,int, or fixed, and perhaps string. various counters and screens which 
are set by the user at the scanner could be reported this way.

allan

> Thanks.
>
> Étienne.
>

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