RE: [hpoj-devel] COLOR_24_BIT Problems

SourceForge Headquarters 225 Broadway Suite 1600 San Diego, CA 92101 +1 (858) 422-6466

Hi, James.

James Klicman wrote:
> I have been experimenting with cmdline.c and have run into a
> strange problem that occurs when I set OID_SCAN_PIXEL_DATA_TYPE to
> COLOR_24_BIT. I'm not sure if the problem is related to your warning
> about using multiple MLC channels, since the channel will be required
> to return alot more data. One symptom of the problem is that 
> the Raster
> Data Records seem to have zero Raster Data and the program hangs while
> reading the MLC scan channel. There are no errors generated as far as
> I can tell. I also need to turn the scanner off/on and reload 
> ieee12844
> and ieee12844pp to get BILEVEL_THRESHHOLD to work again.
The hang and the need to reload ieee12844*.o would point to the driver
problem I mentioned.

> Here is the execution output of the modified cmdline.c, in this
> version I also set OID_SCAN_COMPRESSION to JPEG_COMPRESSION and
> OID_SCAN_COMPRESSION_FACTOR to 50.
Despite the documentation, JPEG compression isn't necessarily supported on
all models.  I would suggest starting with raw (no compression).  This could
be why you're getting empty (header-only) packets.

I'm not very good at decoding PML packets, but I'll try here.  I'm assuming
these are replies from get or set requests.
> Got 15 characters:
> 84 87 18 01 87 00 05 01 02 02 01 01 08 01 32 
1.2.2.1.1 -- scan contrast -- 50

> 84 87 18 01 87 00 05 01 02 02 01 03 04 01 18 
1.2.2.1.3 -- pixel data type -- 24 -- 24-bit color

> 84 87 18 01 87 00 05 01 02 02 01 04 04 01 06 
1.2.2.1.4 -- compression type -- 6 -- JPEG

> 84 87 18 01 87 00 05 01 02 02 01 05 08 01 32 
1.2.2.1.5 -- compression factor -- 50

> 84 00 00 04 01 05 01 04 08 01 64 
1.5.1.4 -- copier reduction -- 100 (I don't know if this affects scans)

> 84 00 00 05 01 02 02 01 0C 04 01 01 
1.2.2.1.12 -- scan upload -- 1 -- idle

> 84 00 00 04 01 01 01 12 08 01 5A 
1.1.1.18 -- upload timeout -- 0x5A 

> 85 00 00 05 01 02 02 01 0C 04 01 01 
1.2.2.1.12 -- scan upload state -- 1 -- idle

> 84 00 00 05 01 02 02 01 0C 04 01 02 
1.2.2.1.12 -- scan upload state -- 2 -- start

> 07 00 05 01 02 02 01 0C 04 01 03 
1.2.2.1.12 -- scan upload state -- 3 -- in progress

Don't forget to set the scan resolution (1.2.2.1.2), although it may default
to a reasonable value.

David