Re: [hpoj-devel] more PML gray/color scanning support

[Joe P. <joe...@sn...>]

On Monday 30 April 2001 07:01 am, David Paschal wrote:
> Hi,
>
> I just checked in some more changes to enable grayscale and color PML
> scanning on the OfficeJets.  These new modes save the image as a JPEG
> file rather than a PNM file (which turned out to be quite non-trivial!).
> I made some other bug fixes and enhancements to "ptal-hp -scan" as well.
>
> So far I have tested this new functionality on an OfficeJet 700, LaserJet
> 1100A, and LaserJet 3200m.  It should also work on the OfficeJet 600 and
> PSC 300 series, and it may or may not work on the OfficeJet 500 and T
> series.  I will test with these other models later this week, but of course
> I will always happily accept success or failure reports from others.  :-)

Scanning in color worked on the 600, but with some problems:

The document printed at a smaller size than the original ( at about 60% of 
the scanned doc).

Printed at the bottom of the page was a large gray rectangular area that was 
not part of the original document.

When I opened the scanned page in gimp, the gray area gave the impression 
that the scan had continued past the end of the paper.

>
> There are several issues with ptal-hp documented at
> "http://hpoj.sourceforge.net/todo.shtml", including:
>
> - "ptal-hp -scan" doesn't properly set the number of raster lines in a
> JPEG image, so your image viewer/editor may report a "corrupt JPEG data"
> error.

The pixie image tool complained about a "premature end of data segment" in 
the out.jpg file, then crashed. gimp 1.2.1 also complained. It did open the 
file, but didn't handle it well.


>
> "ptal-hp -scan" may hang on OfficeJets when scanning in "-bw" or "-bwht"
> modes unless you give the "-res 300" switch.
>
> - If you get ptal-mlcd error messages about lookupChannel failures while
> scanning with ptal-hp (probably on the OfficeJet 500/600/700/PSC300), try
> invoking ptal-mlcd with the "-porttype spp" option.  This may be an ECP
> signalling bug, possibly due to waiting to long to go back to forward.

I don't think I've seen the 'lookupChannel' error yet.


-- 
Joe