[sane-devel] [ANNOUNCE] rts8891 backend

[stef]

	Hello,

	I am currently working on a SANE backend for rts8891 based scanner such as 
the HP Scanjet 4470c and UMAX Astra 4400/4450. I have set up a page at 
http://stef.dev.free.fr where you can get the current work in progress.

What is working:
	- origin detection, gain, offset and shading calibration
	- 75, 150, 300 and 600 dpi color modes are working fine
	- 1200 dpi almost work, the data needs to be realigned for some "saw-tooth"  
                   effect

Things to fix:
	- warming up, currently the first scan gives "overlighted" colors

Features to add:
	- gray level scans
	- button reading

	The transparency adapter isn't supported at all since I don't have one to 
test. During tests I wiped out the data in the NVRAM, and now the USB id of 
the scanner has gone from 0x03f0/0x0805 (HP4470c) to 0x1606/0x0070 (UMAX 
Astra 4400). I disabled those dangerous acesses to NVRAM, and such thing 
won't happen again.
	However, this confuses the windows driver, and I'm not able to generate logs 
for the gray level scans. I installed the driver for the UMAX 4400 which 
detected the scanner but crashed everytime I tried to scan. So I'd be glad if 
someone could record USB activity for gray preview and 150, 300, 600 and 1200 
dpi gray scans and send me these logs.

	I expect to have it finished and hopefully ready for inclusion in regular 
SANE CVS by december.

	While this backend is written from scratch, some clues of the working of the 
scanner were gathered from the hp44x0backend (by Johannes Hub) and the hp3500 
(by Troy Rollo).

Regards,
	Stef