hp-backend: 2nd try parallel support and new ADF support

Martin Huber (hu@garfield.m.isar.de)
Wed, 16 Dec 1998 23:20:14 +0100 (MET)

Peter Kirchgessner wrote:

>
> >
> >I tried this backend with an HP "ScanJet ADF" (identified
> >by find-scanner: found processor "HP C6270A 3824").
> >I found no effect of the "Scan from ADF" button.
> >If a document is loaded in the ADF, it will be scanned,
> >regardless if "Scan from ADF" is checked or not.
> >
>
> How about the button "change document" in xscanimage.
> Does it appear and does it eject the page that is in the scanner and
> load the next one ?
>

I did some tests for this.

1. There should be no paper loaded in the ADF when xscanimage is started.
Else the preview window has hight 0 and is double as wide as normal.
The geometry filed shows top-left x 0.0, top left y 0.0,
bottom right x 21.6, bottom right y 0.0 (The first -top left x- slide
is at the left and, the three others are on the right end).
No scan is possible until xscanimage is closed, the paper is removed
from the ADF and xscanimage is started again.

2. No paper in ADF, xscanimage started, preview window opened.
Some documents put in ADF.
"Change documents" pressed.
The preview window gets double as wide as it was before.
A sheet of paper is loaded from the ADF and pulled in until to
the point where scanning would start.
xscanimage crashes with
hp-accessor.c:834: failed assertion `val_mm >= 0'
Abort (core dumped)

3. One document is still inside the ADF (how to get it out?)
xscanimage started again.
Bottom right y is still 0.0.
The preview window has hight 0 an is double as wide as normal.
"Start preview" aborts xscanimage with the same "faild assertion"
message as above.

4. restart xscanimage, geometry as before. No preview window opened, but
"Scan" pressed. (How should I get the paper out of the scanner?)
The "Aquire image" popup appears and freezes.
After some time the popup disappears, and the scanner sounds as if
it would move a centimeter force and back (realign?)
The xscan window is as before.
Another "Scan" ejects the paper loaded before and pulls in the next one.
(Hugh!). Removed the rest of the paper from the ADF.
After some time the loaded document is scanned, but the resulting out.pnm
is only 349 bytes long.

5. restarted xscanimage. Everything looks normal.
Put some documents in th ADF. "Scan from ADF" not checked.
Aquire preview. One sheet of paper is taken from the ADF and scanned.
The preview result is normal.
Pressed scan. The next document is scanned.

6. Removed all documents from the ADF.
Terminated xscanimage and started again.
Put some documents into the ADF.
Opened preview window. Still everything normal.
Changed "Scan Mode" from Lineart to Color.
The preview window gets the double size, and the Top-Left y slide
jumps to the right edge and shows 0.0.
Aquire Preview results in
hp-accessor.c:834: failed assertion `val_mm >= 0'
Abort (core dumped).

7. Removed all paper from the ADF.
Started xscanimage.
Put paper into the ADF.
Checked "Scan from ADF".
Opened Preview window and changed Scan mode from Lineart to Color.
Same behaviour as above.

8. Same preparation as 7.
Pressing "Scan" insteat of "Aquire Preview" results in a "successful"
scan of a zero hight picture. At least it does not crash.

9. xscanimage started, paper in ADF, Scan from ADF checked.
Change document pressed.
A sheet of paper is loaded from the ADF and pulled in until to
the point where scanning would start.
Nothing happens. Further presses to "Change document" have no effect.
Scan scans the document and procduces a 349 byte out.pnm (i.e. a
zero hicht picture).

It looks as if xscanimage reads a bad geomety value from the scanner when
xscanimage is started, the Scan Mode is changed or Change document is
pressed. Attempting to get a preview in this mode crashes.
Scan from ADF seems to have no effect.

--martin

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