[sane-devel] HP5470c scanner nearly working!

[Henning Meier-Geinitz]

Hi,

On Sun, Feb 23, 2003 at 10:25:46AM +1100, Martijn van Oosterhout wrote:
> On Sat, Feb 22, 2003 at 03:54:37PM +0100, Henning Meier-Geinitz wrote:
> > Some tips are also in doc/backend-writing.txt. E.g. for writing
> > portable code.
> 
> Thanks, I found them. I'm reading them now. Actually, I have one addition
> for the backend-writing.txt

Thanks, I will add it.

> > > Can I safely assume the caller of sane_read will provide a buffer >10K.
> > > Probably not hey? So I have to buffer possibly down to the subpixel level.
> > 
> > No. The buffer can be as low as 1 byte. In backends that need to do
> > image manipulation, usually a buffer of one or multiple scan lines is
> > used. Especially if you need to do line distance correction (CCD
> > scanners), you may need 10 or more lines of each color.
> 
> Heh. I wonder if all backends really support a buffer that small. Nice
> stress test :)

scanimage -T and frontend/tstbackend both try 1 byte per read scans.
So every backend in the sane distribution should be able to do this :-)

Bye,
  Henning