Re: [Hp3300backend-devel] HP3400/4300 vertical resolution issue test

[Bertrik S. <be...@zo...>]

I just released a new source zip at sourceforge for this test,
because it may not be trivial to get the latest version from CVS.

To do the tests, you should change line 433 of hp3300c.c:
    _ConvertMotorTable(abData0000, abMotor, sizeof(abData0000), 300);
 and line 438 of hp3300c.c:
    _ConvertMotorTable(abData0400, abMotor, sizeof(abData0400), 300);

I have strong suspicions that table abData0000 contains some kind
of motor profile for moving the scanner head when it is not
scanning (when moving back after a scan for example).
Table abData0400 probably contains a motor profile for moving the
scanner head while it is scanning. The first value of this table
is also equal to the number that I use to set a resolution of
300 lpi on my HP3300.

During initial testing it was discovered that setting both tables
to double their default value resulted in a scan at 600 lpi, which
is also double the default resolution of 300 dpi.

Please try to change the number 300 into 150 or 600, recompile and
do a small scan using (for example):
'./hp3300 scan 300 300 test.pnm'
Do not try any other numbers than 150, 300, 600 yet.
Then check the scanned image to see what the aspect ratio of the
image is. A normal aspect ratio of 1 vertical : 1 horizontal
means 150 lpi, a ratio of 2 vertical : 1 horizontal is 300 dpi
and a ratio of 4 vertical : 1 horizontal is 600 dpi, etc.
Also during scanning and during other movement of the scanner head
try to hear if the scanner makes a different sound or shows any
other odd behaviour.

I propose to number the test cases like this:
1) line 433: number = 300, line 438: number = 300 -> 300 dpi scan
2) line 433: number = 300, line 438: number = 600
3) line 433: number = 600, line 438: number = 300
4) line 433: number = 600, line 438: number = 600 -> 600 dpi scan
5) line 433: number = 300, line 438: number = 150 -> 150 dpi scan?
6) line 433: number = 150, line 438: number = 300
7) line 433: number = 150, line 438: number = 150
8) line 433: number = 600, line 438: number = 150
9) line 433: number = 150, line 438: number = 600
Roughly in order of safety (1 = safest test).

It may be possible that the scanner makes a high pitched noise
(because the stepper motor may be stepped too quickly),
especially when using the number 150 in lines 433 or 438.
In that case, I recommend to quickly turn off the scanner.

So please keep in mind that if you run these tests, you are doing
so at your own risk. If you think it is too risky, then don't
do it!

Good luck testing,
Bertrik