- This topic has 17 replies, 3 voices, and was last updated 1 month ago by .
-
Posts
-
Hi all,
i’m trying to get some informations (eg. barcode) from scanned page. I’ve downloaded a NETMasters code example, implemented two structures –
[StructLayout(LayoutKind.Sequential, Pack = 2)]
internal struct TwInfo
{
public short InfoID;
public short ItemType;
public short NumItems;
public short CondCode;
public int Item;
}
[StructLayout(LayoutKind.Sequential, Pack = 2)]
internal class TwExtImageInfo
{
public int NumInfos;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 1)]
public TwInfo Info;
}
, enum
internal enum TwEImgInf: short {
...
formvertdocoffset = 0x1218,
barcodecount = 0x1219,
barcodeconfidence = 0x121a,
...
}
and function
[DllImport("twain_32.dll", EntryPoint = "#1")]
private static extern TwRC DSextImgInfo([In, Out] TwIdentity origin, [In, Out] TwIdentity dest, TwDG dg, TwDAT dat, TwMSG msg, TwExtImageInfo extimginf );
according to specification, i’m trying to get information right after i recieve XFERDONE. My code is :
TwExtImageInfo extinf = new TwExtImageInfo();
extinf.NumInfos = 1;
extinf.Info.CondCode = 0;
extinf.Info.InfoID = (short)TwEImgInf.barcodecount;
extinf.Info.ItemType = (short)TwType.Int32;
extinf.Info.NumItems = 0;
extinf.Info.CondCode = 0;
rc = DSextImgInfo(appid, srcds, TwDG.Image, TwDAT.ExtImageInfo, wMSG.Get, extinf);
i’m allways get error “cannot marshal field Info of type TwExtImageInfo”. can anyone help me with this? i’m nearly mad… 🙁
i took a somewhat different approach, i asked for every standard extInfo (not just the barcode info) but if you want to translate the classes from vb.net the code is over at http://www.codeplex.com/opentwain. if you run the sample app the extInfo will output in your ide.
.
what driver are you using? Ther is typically a driver on the cd that came with you hp scanner that has a name ‘hp commercial twain %model number%’
check if you get barcode info out of the extInfo with the commercial driver, and you may have to look into their custom extInfo, I’ll often go looking for another 100 or 2 over the standard set of id for extra/undocumented info
.
the scanner came with a cd. search the cd for a directory that contains the word ‘commercial’
You’ll like that driver much much more (at least I typically do)I’ve tried finding those drivers online but I seldom have much success,.. though that could just be my poor internet searching skills… hard to say.
.
on the other hand, i seem to remember that the toolkit would display all sorts of info if you set the logging to full…
if run twack_32 and set the message level to full and acquire do you see any mention of a barcode in the dialogs (assuming you are scanning something with a barcode)?
.
do you see CAP_ENABLEDSUIONLY under supportedCaps?
is a read only Cap, it just indicates that the device supports the capability (you can’t set it)
then my last idea for getting extInfo out of the device is to run the device from opentwain. If you start the guiharness project form opentwain with your debugger, you should see a whole bunch of stuff scroll thru your output window (vs 2005) some of the stuff that scrolls by will be all of the extInfo.
…and if i misremember the current build I posted and if i happened to have commented out the method that outputs all the extInfo lemme know and I’ll tell you where/how do re-enable the output.
.
was it an AccessViolationException? and was it due to the ptr being null or 0?
I’ll look back thru the code, and one more thing – you are feeding a document that contains a valid barcode right?
.
did m_ReadStr255 loop thru at all before it threw or was it the first pass thru that went kaboom? wondering if they put any text in there at all or not,..
.