In the "check if x/y ranges are valid" section of the attach() function, the
enum source_mode was being used instead of source_mode_dim. Since these two
enums are very similar, it's not likely this change will affect anything, but
it does fix the compiler warning.
Previously I had changed the USB ID of this scanner from 0x0a18 back to
0x0a19, believing a previous commit to have been in error since it went
unmentioned in the commit log and duplicated the AV600U Plus scanner's USB
IDs. Rolf Würdemann reported that his AV610 scanner used the 0x0a18 ID and
that it wasn't compatible with the AV_INT_STATUS flag. This commit reverts
my USB ID changes and removes the AV_INT_STATUS flag for the AV610.
However, because this scanner shares its USB ID with the AV600U Plus, it's
possible that the AV600U Plus may require that the AV_INT_STATUS flag be set
in order to function, and thus will break with this change. The code, as
it's written, isn't designed to deal well with the possibility of shared USB
IDs, so I'll wait to see if this actually becomes a problem before embarking
on the lengthy challenge of getting that to work.
Keep track of the number of lines to flip on the reverse page using a negative
number. This uses the ill-advised principle of overloading the meaning of a
variable. Still, it kind of makes sense because these lines are upside down,
so the number should be "upside down" too. Besides, leaving it as a positive
number trips up the code which does page padding, which would require even
more special case code.
Adding sane_reload_devices() to sane_init() required sane_init() to be moved
below the sane_reload_devices() declaration. This restores the original
functionality present before I split the sane_reload_devices() code out of
sane_init() so that it could be called from sane_get_devices().
In a previous patch, I attempted to avoid the possibility of a page remaining
partially inside the ADF unit of a flipping duplex scanner after a scan.
Unfortunately, I introduced a bug where the backside page was accidentally
returned to the client in addition to being cached. This was because I had
a misunderstanding of the post-processing code. This patch skips the post-
processing section altogether, avoiding any unnecessary post-processing and
subsequent unwanted output. The other alternative here was to try to monkey
with the buffers (as is done for LINE deinterlacing), but I felt this would
be harder to implement and even harder to debug in the future.
This fix correctly initializes the AV220-G by querying the firmware.
Added the correct option to support the interlaced duplex format used by
this unit.
Flipping duplex scanners must flip the page in order to scan the back side
of the page. With this option set (which is the default), the page is
flipped back to the original orientation. This is important if you have
a stack of papers. However, if you don't care if every page ends up
flipped compared to how it was loaded, turning this option off might save
some scanning time as the paper won't have to be pulled back through the
ADF mechanism a third time.
Although the flipping duplexer is working, there are some issues relating to
the mechanics of physically flipping paper. First among these is that the
back side of each page is physically scanned in reverse, resulting in an
upside down image. Secondly, the page is held partially in the ADF
mechanism while waiting for the frontend to make another scan request for
the back side image, thus resulting in a stuck page if the frontend fails to
follow through.
My solution to these problems is to treat page flipping as an extreme
extension of interlaced scanning; page level interlacing. This means making
another scan request on behalf of the frontend, and writing the resulting
image to a file as would have been done if the page were line interlaced.
We would have had to write this image to a file anyway to flip the image
right-side up, so we aren't doing any extra work, and technique allows us to
reuse existing code for most of the file handling. The reader_process()
function is called again (recursively) after scanning the front page. We
use the page length of the front side to determine the length of the back,
so that we can write the lines to the file starting at the end and working
towards the beginning (thus flipping the image).
A side effect of this solution was the discovery that the scanner must be
reminded that the paper needs to be re-flipped after each scan, so
set_window() must also be called in reader_process() before starting the
second scan.
Finally, with this change, a minor bug was exposed where frontends were
given the number of lines which would be scanned, which makes sense in
flatbed mode, but does not make sense for an ADF, where the page may be
smaller than the scan window. The code was changed to follow the
specifications, returning -1 in ADF mode (when the length cannot be
determined).
After fixing the duplexer initialization, it became clear that the code was
mirroring the back pages. Since the scanner already supports page
mirroring internally with an optional bit setting (which was already set)
it made the most sense to simplify the code base and remove the variable.
For scanners which potentially have flipping duplexers, only enable
duplexing if there is an ADF present. This leads to the next problem, that
the flipping duplexers (present only on the HP 8200 series AFAIK) don't
always seem to be properly configured when powered up. To solve this some
magical values are written to magical memory locations, and some more
magical status is read back, causing an apparent firmware reset which
blocks communication for a short period of time. See adf_reset() for
details.
Added the AV_ADF_FLIPPING_DUPLEX flag to activate the flipping duplex code
only for models known to have such duplexing ADFs. Prior to this a doubious
huristic was used to guess when the hardware had a flipping duplex unit.
The additional_probe variable protected add_source_mode() and
add_color_mode() from being entered upon subsequent calls. These functions
were patched to not insert duplicate records in this case, removing the
need for the gatekeeper variable.
Until now the code has been changing the frontend supplied pointer to point
to our internal data structure. There are two problems with this. It
orphans the data previously associated with that pointer, which causes a
memory leak. It also gives the frontend the ability to munge our internal
data structure.
The only downside to this change is the possibility that a frontend took the
spec too literally and merely supplies a pointer but does not allocate
storage space for the result. Technically, the spec is a bit vague on this
point, because it does not specifically state who should allocate the
structure, but I feel a reasonable programmer would guess that space
allocation is a frontend obligation.
There was an old TODO in the code which suggests creating an option for using
the paper_length field to detect double feeds in the ADF. I've added it as
an option, but set the default to not use it since it might cause older
scanners to get confused.
I felt that the ehancements group was doing double duity for image tuning and
other more hardware related options. This new group takes ownership of those.
I'm not happy with the name, but that can always be changed.
Added support for the Avision AV210D2+ scanner. This is the first scanner
to require the use of the gray filter bits, so code was added to enable them.
Regenerated description file to reflect this change.
Moved device init code from sane_init() to the newly created
sane_reload_devices() function, which is now called from sane_get_devices().
This means that device initialization now happens when sane_get_devices() is
called, not when sane_init() is called.
Replaced the clever, yet totally confusing, code using the "adf_mode"
variable. This variable was used with a complex interaction of bit shifts
and subtraction indirectly influnced by the value of s->source_mode. The
replacement code direct references s->source_mode instead, simplifying
things greatly. This change is functionally identical.
As a side note, the adf_mode code allowed "ADF Rear" scanners, in addition to
"ADF Duplex" scanners, to enter the section of code normally used for (HP)
duplex scanners. It's not clear if this was the intended effect, or if, as
the comments suggest, this was an unnoticed side effect caused by the
confusing code. The point is moot, however, because prior in the code, the
ADF Duplex flag is set anytime the ADF Rear flag is set. As long as all
ADF Rear scanners are duplex scanners this shouldn't be a problem.
Changed the AVISION_FILTER_* defines to their final values rather than
bit-shifting them prior to use. This make reading the code much easier
since no mental calculation is necessary to determine what the final
bit-pattern/value will be.
Wrap scanner entries with duplicate USB ids with ifdefs so they will not be
compiled. This shortens the search for new scanners because we don't try
the same USB id more than once.
the same and already work, but this change will reflect that fact on the
website.
- Generated a new version of doc/descriptions/avision.desc from avision.c.
the AV610, and added a comment for the @V5100 in avision.c.
- Generated a new version of doc/descriptions/avision.desc from avision.c.
This restores information lost with my last update. I've intentionally
seperated these changes so that they can be more easily understood.
Mike Kelly