Help

[Gabri]

Hello,

I’m really new to using TWAIN… and I have a lot of questions. Here is one.
I’m working to a project that requests multi image acquisition. More exactly the output of each single document scanning are 4 images (2 front and 2 rear) , more frames and a string (from a MICR codeline). The problem is that each image have is own setting (like resolution, gray level etc.)
Any idea to do this with TWAIN 1.9.
A optimal time for do the images acquisition is also requested.
What about the string?

Thank you

[gabe]

Unless your device supports CAP_EXTENDEDCAPS seperate settings means seperate acquisition – you can’t renegotiate capabilities while an acquisition is underway without CAP_EXTENDEDCAPS.

The mirc string via twain is trickier. If you post the model you may be more help from someone with (more) mirc experience.
If I were trying to find it I would (start sweating, then) run a Msg_Get a few hundred past x8000 to see if there is a customCap out there waiting with string info I’d look thru all of the standard extednded imageinfo and another 2 or 300 hundered to see if the mirc string is there.

Otherwise you’re at the mercy of the vendor’s support staff and documentation for how to get the info out.

the part where you ask “A optimal time for do the images acquisition is also requested.” … you’ll have to try asking again with different word. I didn’t understand what you’re looking for there.

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[Gabri]

Sorry, I was not very clear before.

The story is: one client have a library that manages check scanner. My job is to answer to this question: it is possible to add a level to this library for transform it in a TWAIN-compliant software?
I find this quite difficult because my experience with TWAIN is 0.

Some problems now:
For each check the output is 2 front images, 2 rare images, few snippets images and one MICR string.

First problem is that the images have different resolutions, grey depth etc. How can I model this with TWAIN? I think to create custom capabilities for each image for do this settings, but I don’t know if it is a good idea.

With MICR string I think to do like this: do a custom capability for this and a custom event. If the MICR is ready the Source send this event and like this the application will know to get the string using MSG_GET. Is it possible with TWAIN, isn’t it?

The client have also performance problems, my questions are:
1) Is it heavy a negotiation in state 5 and 6?
2) Of course, a TWAIN level on top of the existing library have is heavy, but how much?

Thanks for any idea

[gabe]

Just so I’m sure I understand then – You’re writing the twain driver – you are not trying to connect to an existing driver.

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[Gabri]

Correct, I’m writing the twain driver (the existing one is not TWAIN)

[gabe]

Ah, then my advise comes from someone with experience consuming a driver not from one with experience writing one, but here it is.

Are there really settings for each of the 4 images you are going to return? Or is it the case that you ‘re going to return 4 images and the user has no control? If you are always going to return 4 images and the user doesn’t control the resoltions (or need to) then I don’t think it is a very big deal – Report the resolution that you return in the twImageInfo after you send the image and it’ll get worked out.
Or, support ExtendedCaps. But,.. I dunno. I could be the case that ExtendedCaps gets a lot more use from other developers but I don’t use it at all,.. and then again maybe I would use extendedCaps more if I saw it being supported by more vendors – hard to say from here

I would put the mirc string in a custom extendedImageInfo, over 0x8000 is reserved for custom. Just return the twStr255 in there and I think a lot of people will bump into it even without your extremely well documented api available from your website or your spectacular support staff who know exactly what ‘custom extendedImageInfo’ means and what the Id is for your Mirc string.

Also, (and this next part has nothing to do with your question) it wouldn’t hurt to include your twain header on your CD for people writing apps. Kodak does this and I gotta say, it helps a lot.

If you haven’t looked thru the GenDs sample from Dosadi, it may help you.
http://www.dosadi.com/gends.htm

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[Gabri]

Thanks for your help

What about performance & TWAIN, any idea?

[gabe]

what are you wondering when you ask performance and twain?

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