Re: HP support

David Mosberger-Tang (davidm@azstarnet.com)
Wed, 28 May 1997 08:58:32 -0700

>>>>> On Wed, 28 May 1997 10:48:56 +0000, "Dr. Michael Grimm" <Michael.Grimm@Schering.DE> said:

Woramut> The sliders for brightness and contrast work fine for me.

Michael> I can second this, but like to add the following observation on the
Michael> "SANE_DEBUG_HP=3 scanimage -h -d hp" output:

Michael> $> [sanei_init_debug]: Setting debug level of hp to 3.
Michael> $> [hp] attach: opening /dev/scanner
Michael> $> [hp] attach: sending INQUIRY
Michael> $> [hp] attach: sending TEST_UNIT_READY
Michael> $> [hp] attach: found HP ScanJet model C5110A, x=-1039.35--1038.97mm,
Michael> ^ ????
Michael> $> y=-1039.35--1038.97mm, resolution=12-1600dpi
Michael> ^ ^^^^ ????

Michael> These signs, dimensions and the resolution number are
Michael> wrong, aren't they ? According to the specs the 5P has an
Michael> optical resolution of 300 dpi and an enhanced resolution of
Michael> 1200 dpi; the maximum document size is 216 x 297 mm.

Argh---checking the latest docs, I found that HP decided to drop
support for inquiring/setting the scan area in decipoints. According
the docs, the 5p supports the pixel-unit commands only... ;-( The only
good news is that all HP scanners support the pixel-unit commands, so
the HP backend should be converted to avoid decipoints entirely.

As for the resolution: my docs do confirm that the scan resolution for
the 5p is 12 to 1600 dpi---maybe your scanner is better than
advertised? ;-)

Worawut> However, the preview still does not work.

Given that the x/y extents are complete garbage, I'm surprised it
doesn't go up in flames.

Can somebody with an HP scanner change the HP backend to use the pixel
unit commands instead of the decipoint commands? It's not too hard
and I could do it, except that I don't have time and that it's not
much fun to write code that I can't test.

If you need docs, I _think_ it would be no problem if I'd give you the
relevant PDF file that HP puts out.

--david

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