GNOME Bugzilla – Bug 633585
GIMP does not detect all TWAIN scanners
Last modified: 2011-03-18 00:03:14 UTC
After clicking File -> Scannner/Camera..., the "Select Scanner" dialog comes up. On my computer, there are two scanners installed: EPSON DX7000F All-in-one printer/scanner Canon Lide 210 flatbed scanner The dialog displays the Epson scanner twice, once without the prefix "WIA", and once without it. Selecting the version without the "WIA" prefix brings up the EPSON Scan dialog with all the advanced options, selecting the version with the "WIA" prefix brings up the standard WIA-dialog. However, for the Canon Lide 210, there is only a version with "WIA" prefix. There is no way to bring up the advanced "ScanGear" dialog. (I expected to find a Lide 210 entry without a "WIA" prefix.) Scangear is installed correctly, however. I have tested this with the program called "PhotoScore" (to scan sheet music), which I am currently evaluating. In it's scanner setup dialog, both the options with and without "WIA"-prefix come up, for the EPSON and Canon scanner. PhotoScore is able to directly invoke the Canon ScanGear dialog box. I have also tested this using the "TWainable" plugin for Paint.NET: http://forums.getpaint.net/index.php?/topic/15384-twainable-acquire-from-twain-sources-v021-updated-4-oct-2010/ As I am on Vista x64, the plugin does not work in Paint.NET, but there recently was an updated version that can run stand-alone. Direct Downloadlink: http://forums.getpaint.net/index.php?app=core&module=attach§ion=attach&attach_id=4559 If I unzip this program/plugin and start it, it has an option to select the scanner you want to use. Again, both the options with and without "WIA"-prefix come up, and the "Twainable" program/plugin is able to invoke the Canon ScanGear dialog box. As I can detect the Canon LIDE 210 scanner with two different and totally unrelated programs, it is my opinion that there is a bug in The GIMP, causing it to not detect all installed scanning possibilities.
Basically a duplicate of bug #143855.
As far as I can see, this is not a duplicate of that bug. Bug 143855 describes not being able to scan or getting a partially black image. In my setup, Gimp has always scanned without any problems, using the EPSON Scan interface, which is launched by selecting the Epson scanner without "WIA" prefixed. (Using WIA to scan with the EPSON DX7000F All-in-one also works fine.) The Canon-scanner also works fine using the Windows WIA interface, but there is no way to launch the ScanGear interface as it is not in the list to be selected. I am sure that if GIMP can detect the TWAIN version of the LIDE 210 to be able to launch ScanGear, it'd work just fine. I am puzzled why GIMP detects and uses the EPSON Scan interface without problems, while not being able to detect the Canon Scangear one. (By the way, I am assuming that the interfaces that are not prefixed by "WIA" are TWAIN ones.)
However, bug 143855 referres to some other bugs, one of which seems indeed to be similar: bug 606193 bug 152789 The other bugs referenced in bug 143855 have some sort of problem with the TwAIN interface, but most of them are different. Are all bugs related to the TWAIN interface classified as being duplicates of bug 143855?
Did another test by downloading and installing a trial of Paint Shop Pro X3. Through "File -> Import -> From Scanner or Camera" the program is able to use the WIA interfaces to both scanners. Through "File -> Import -> Twain Source", Paint Shop Pro X3 is able to use bot the WIA interfaces as wel as the Epson Scan and Canon ScanGear interfaces.
But are you sure that these other applications aren't using some other API than TWAIN to see these other scanners and/or scanner interfaces? That sounds as the most likely explanation to me, that the "WIA" means exactly that, a different API, not related to TWAIN. (And http://en.wikipedia.org/wiki/Windows_Image_Acquisition seems to agree.) This bug should either be resolved as NOTABUG, or retitled as "GIMP should support Windows Image Acquisition API" and thus be an enhancement request.)
For Windows, there are no other commonly used API's, but there's one thing that should be accounted for which makes this matter more complicated: WIA exposes a TWAIN-compatible API, to make TWAIN-only applications capable of using the WIA-scanner dialog built into Windows XP and upward. I think The GIMP is detecting this API when it displays the "WIA"-versions of my scanners, and it works fine: when selected, the WIA dialog pops up. However, this WIA dialog is very limited. It does not provide a lot of functionality. TWAIN has much greater capabilities. EPSON Scan and Canon ScanGear are both built on the TWAIN protocol. All other applications that I tested support this and they find both EPSON Scan and ScanGear. Paint Shop Pro X3* Twainable-plugin for Paint.NET PhotoScore 6 They all detect the EPSON Scan and Canon ScanGear user interfaces and they can launch them. In addition, they also detect the WIA user interface which is exposed by the TWAIN-protocol built into WIA. GIMP fials to detect Canon ScanGear for some reason, while it does find EPSON Scan. If I use a program that only supports WIA (such as PAINT.NET itself), then ONLY the two WIA user interfaces can be used; EPSON Scan and ScanGear are not detected. If you want I can create some screenshots showing the differences between the applications and the WIA and TWAIN scanner selection boxes. *PSP X3 supports both TWAIN and WIA. Therefore, I can use the WIA user interface trhough the WIA-selection dialog, but also through the TWAIN selection-dialog.
FWIW, with my Canon scanner (CanoScan 8800F), scanning from GIMP (self-built 2.6) (selecting the scanner without "WIA" in its name), *does* bring up the ScanGear user interface.
I am sure that it would work perfectly fine over here, but GIMP does not even give me the choice to select the scanner. It does not detect it the TWAIN GUI, while all other programs I have tested do. The Epson DX7000F is an older printer. It's more than 3 years on the market at the moment, whereas the Lide 210 is Canon's newest scanner. It has just been introduced. Could it be that the LIDE 210 uses a very new TWAIN version, one that GIMP does not yet support? The programs I have tested it with (Paint Shop Pro X3, PhotoScore 6 and the TWAINABLE plugin for Paint.NET) are all very new too.
> Could it be that the LIDE 210 uses a very new TWAIN version, > one that GIMP does not yet support? I guess it could be that, sure. Although you are wrong on the "yet" count. Nobody is maintaining the TWAIN code in GIMP. So as you seem to know about these things, please, a patch would be most welcome.
To my regret, I only know which scanner standards there are which selection dialog should present me with which choices if it is working correctly. I do not have any knowledge about the technical side of these standards. Allthough I am happy to try and further troubleshoot the problem, there is no way for me to update the TWAIN code myself. While I can program, I just don't have enough knowledge about the TWAIN standard and GIMP source code.
But you can learn! The twain plug-in code is not that hard, it is plain C, it does not use any obscure programming methodologies.
The program's code will not be the problem... also, learning the TWAIN standard through TWAIN.org would also not be that hard. The problem is time: I don't have the time to learn about all this between work, studies, and courses. I'm programming my * off as it is (in C#, C++ and PHP) for the moment. I'm very sorry, but at this point in time I do not have the possibility to take on yet another project in my spare time.
The reason that I suggested to close this as duplicate of bug #143855 is that we use this report for all TWAIN problems. Basically it states that the plug-in is broken and looking for a maintainer.
Closing all TWAIN bugs as duplicates of "twain is broken", it is so broken that it doesn't make sense to keep more than one bug open for it. *** This bug has been marked as a duplicate of bug 143855 ***