| T O P I C R E V I E W |
| JonRobertson |
Posted - Oct 27 2011 : 15:39:41
Our application has supported scanning via Twain for years. Now that we've switched to ImageEn for scanning, I'm considering adding support for scanning via WIA.
Are there many scanners that have WIA drivers but not Twain drivers?
Aside from supporting hardware that does not have a Twain driver, is there any other reason to add support for scanning via WIA?
On my workstation (quad core 2.4Ghz, Win 7 Enterprise 64-bit, 4GB RAM), the WIA Select Device dialog takes anywhere from 10 to 30 seconds to be responsive after it appears. Is this typical for WIA?
ImageEn's support for WIA doesn't seem as easy to use as the Twain support.  I'm using the WIAScanner and Multi demos to learn about WIA. And I just spent 20 minutes searching through ImageEn docs and MSDN docs to figure out how to do a duplex scan.
ImageEn's support for WIA scanning is definitely not as polished as Twain. For example, WIA_DUPLEX can't be set if TImageEnMIO.Acquire is used because the function only enables WIA_FEEDER:
WIAParams.SetDeviceProperty(WIA_DPS_DOCUMENT_HANDLING_SELECT, 1); // select feeder
Even if I call WIAParams.SetDeviceProperty(WIA_DPS_DOCUMENT_HANDLING_SELECT, 5) before calling Acquire, Acquire will undo my property. (Tested and confirmed.)
I was able to do a duplex scan by modifying the Multi demo and changing the line in IEMIO.pas:TImageEnMIO.Acquire to:
WIAParams.SetDeviceProperty(WIA_DPS_DOCUMENT_HANDLING_SELECT, 5);
The TImageEnMView showed thumbnails of both sides. 
It would seem ideal to implement properties in WIAParams (TIEWIA) similar to the properties in TWainParams, at least for the functionality common to both interfaces. For example, it would be ideal if I could set ImageEnMView.MIO.WIAParams.DuplexEnabled := True and ImageEnMView.MIO.Acquire would set the appropriate WIA properties. |
| 4 L A T E S T R E P L I E S (Newest First) |
| JonRobertson |
Posted - Nov 01 2011 : 08:07:13
Although TwainParams corresponds very closely to the actual capabilities specified in the Twain specification, many of the TwainParams properties apply to scanning in general.
For example, Contrast, Brightness, XResolution, YResolution, BitDepth, FeederEnabled, AutoFeed, FeederLoaded, DuplexEnabled, and AquireFrameTop/Left/Right/Bottom.
It would be great if TIETWainParams and TIEWia were as similar as possible. If the functionality controlled by a TIETwainParams property also exists for WIA, then add the same property in TIEWia and implement it accordingly. As ImageEn users, we're not concerned about the low level implementation of Twain or WIA. We're just looking for scanning functionality/features and let ImageEn worry about the implementation details.  |
| fab |
Posted - Oct 31 2011 : 03:41:54
quote:
Are you only looking for suggestions? Or if I took the time to change ImageEn code (like adding a DuplexEnabled property to WIAParams and implementing it in .Acquire), would you want those revisions to review and implement in future releases?
Suggestions are welcome! |
| JonRobertson |
Posted - Oct 29 2011 : 08:58:09
quote:
an operating system wrapper is automatically created, so you are able to use Twain anyway.
We've had problems with the WIA<->Twain bridge in the past. It seems that it doesn't support all Twain features, such as duplexing. For the identical scanner, I've seen duplexing work when using the native Twain driver and not work when using the "WIA-" Twain driver.
So when building a list of drivers to choose from, I omit the "WIA-" drivers. I suppose I'll change this to only omit the WIA driver when there the Twain driver is present. So for scanners that only have a WIA driver, users could still use it.
Although in our next release, I'd rather have full support for WIA devices, which I think will be possible now that we're using ImageEn.
quote:
With the help of you and other ImageEn users we hope to continue product improvement.
Are you only looking for suggestions? Or if I took the time to change ImageEn code (like adding a DuplexEnabled property to WIAParams and implementing it in .Acquire), would you want those revisions to review and implement in future releases?
Thanks |
| fab |
Posted - Oct 29 2011 : 05:09:06
quote:
Are there many scanners that have WIA drivers but not Twain drivers?
It could be. However an operating system wrapper is automatically created, so you are able to use Twain anyway.
quote:
On my workstation (quad core 2.4Ghz, Win 7 Enterprise 64-bit, 4GB RAM), the WIA Select Device dialog takes anywhere from 10 to 30 seconds to be responsive after it appears. Is this typical for WIA?
No, this isn't typical. In my tests (even on slow virtual machines) it is almost immediate.
quote:
ImageEn's support for WIA doesn't seem as easy to use as the Twain support. ...
With the help of you and other ImageEn users we hope to continue product improvement. |
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