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- May 25, 2012 at 11:14 pm in reply to: Problem with Setting ICAP_SHADOW parameter with delphitwain #25568
I am not familiar with twister.
What happens with Twack_32.exe TWAIN’s own testing executable?Sorry I can not help with DelphiTwain, I use the Envision library myself.
Clive
Turns out it is NOT totally compatible.
TWAIN_32.DLL accepts empty strings for
version.Info
manufacturer
ProductName
ProductFamilyTWAINDSM.DLL does not.
I have not established whether all or only specific strings are required yet.
Took me a lot of wasted hours to track it down, so I hope it helps someone!
Edit: On further testing it seems that only ProductName is required.
Clive
Thanks gabe.
That is what it looked like.Tracking it is not much use for debugging.
I had a call that was failing and wanted to check the current state in case it had somehow changed on me and I had lost track.The truth turned out to be that trying to set CAP_DUPLEXENABLED to True for the Canon DR-2510C fails if CAP_XFERCOUNT is currently 1 (one).
Any other value does does not fail for example 3.If you want to follow the TWAIN Capability Ordering documentation you have to set CAP_XFERCOUNT twice.
Once before CAP_DUPLEXENABLED to any acceptable value (e.g. 2) and once in its proper place near the end to the actual value you want.Clive
Why do Vendors implement features in their TWAIN UI’s and not provide easy advanced TWAIN capability access to them?
For the same reason they don’t bother to implement many of the capability getters 🙁
As someone that writes sophisticated scanning software that has to support many different scanners and hide the driver’s UI it is my general experience that the writers of TWAIN drivers do not bother to implement most of the capability querying in the TWAIN specification. ISIS drivers do.
This is a real pain as we have to maintain a database of scanners and all their individual features and supported settings.
TWAIN drivers also do not necessarily adhere to the specs. for setting features either. For example DPI might be a range or an enumeration. Brightness might adhere to the 1000 based range or use the ISIS range based upon 127 and, as I said the getter methods to ascertain this may not be implemented.
If you know these features or have the freedom to allow the user access to the drivers UI then the drivers are typically fine for scanning etc.Just my personal experience.
February 5, 2010 at 5:22 pm in reply to: Data sources are disappeared in the Select Source dialog. #25107Bizarre in the extreme!!!
After much debugging and testing over and over…
1. I can see all the drivers in “select source” until before I do an Oracle login.
2. Immediately after the login the Fujitsu driver is missing but the WIA still shows.
3. Next time around (without closing) they are both gone.Here is the weird part:
I change to using the Oracle 10g Instant Client and it starts working.
However, after the first iteration the WIA driver disappears as before; but the Fujitsu driver remains viewable and usable.Unfortunately, it seems some other parts of the application may not like the instant client.
Its very confusing.
1. Yes you are correct about the ds file appearing and disappearing.
2. I see both drivers in most simple applications.
3. My application that runs in a dynamically loaded DLL sees only the WIA driver and I can scan as many docs as I like until I close my form.
After that, if I tell the form to load again it sees no drivers at all.
If I close the host application and re-open it then I see the WIA driver only.BTW: The one machine that runs properly seems to have a lot fewer background apps. running.
Just can not figure out:
a. Why I can not see the regular driver.
b. Why the WIA driver gets lost.
c. If I open another simple app. I have just to load the select source dialog
it sees both drivers, even while my real program (still open) sees none.More Info:
There does not appear to be a*.ds file for the Fujitsu on the machine that works.
Where does it get its info?The machine that did not work did have a *.ds file; but when I renamed it (*.dsx) it made no difference at all.
When do DS files get loaded and are they cached?
i.e. Do I need to reboot to see the result of the renamed ds file?Its our own application using TWAIN 1.
We use a library called ImageLib from Skyline.
TWAIN.log on both machines is identical except that the one that works sees/loads the ‘Fujitsu’ driver and the one that doesn’t loads the ‘WIA’ driver.After renaming wiatwain.ds as per one suggestion. WIA driver still appeared in list.
Also spoke to Fujitsu tech. support who claimed ALL their drivers were built on top of WIA. Don’t know if that is completely true of course.
Hi Catherine,
So far I can not figure out the problem.
It is XP SP3 fully updated. Not an admin. problem.I have advanced(???) to the spot where I have two laptops one that works fine and one that exhibits my customers behavior.
Initially the only two differences I know of are
1. That the one that works uses “Oracle Instant Client” as oppose to the full Oracle Client.
2. That the one that works also has two Canon drivers installed.My intentions tomorrow (unless you have better advice) are
1. Make a full image of the one that fails, so I can get back to it at will.
2. See if I can see any differences in what is loaded in memory using systernals tools.
3. Install a Canon driver (who knows?).
4. Install the Oracle Instant Client in place of the full one.I’m hoping item 2 is a charm.
The other possibility is to wrap an alternate TWAIN component in a class of my own to make it API compatible with my current code and see if that changes anything.
All suggestions welcome.
Thanks again,
Clive - AuthorPosts