Qt4 and TWAIN scanning

[^NyAw^]

Hi,
I'm trying to use Qt4 to scan images using TWAIN on Windows.
I have downloaded Qt TWAIN Package from http://www.cppfrance.com/codes/PACKA...AIN_46374.aspx and I'm modifing it to use Qt 4. The code was created by "Stephan Stapel" using Qt 3.

I've attached the Visual Studio Solution into the zip file to get any help. I've deleted "qtwaininterface" and "qtwainsubstitute".

The problem is that on "BOOL CTwain::ProcessMessage(MSG msg)" method, the line "if(GetRC() != TWRC_NOTDSEVENT)" always returns "TWRC_NOTDSEVENT" and so, the application never recives TWAIN messages.

I would like to port this to Qt 4 for everyone to want to use it and I will send the final version to the author "Stephan Stapel".

Thanks,

[^NyAw^]

Hi,

Any Idea why it don't recive TWAIN messages?
I have scanned only one image by calling "TransferImage()" on "CTwain::Acquire(int numImages)" method:

BOOL CTwain::Acquire(int numImages)
{
    if(DSOpen() || OpenSource())
    {
        SetImageCount(numImages);
        EnableSource(false);
        TransferImage();
        return(true);
        /*
        if(SetImageCount(numImages))
        {
            if(EnableSource(false))
            {
                return TRUE;
            }
        }
        */
    }
    return FALSE;
}

BOOL CTwain::Acquire(int numImages)
{
    if(DSOpen() || OpenSource())
    {
        SetImageCount(numImages);
        EnableSource(false);
        TransferImage();
        return(true);
        /*
        if(SetImageCount(numImages))
        {
            if(EnableSource(false))
            {
                return TRUE;
            }
        }
        */
    }
    return FALSE;
}

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If you call "EnableSource(true)", the UI of scanner will appear but don't response to the scan button, but response to preview button.

Thanks,

[jeffpogo]

Did you ever get the scanning to work? I am interested in it too.

Thank you.

[ajsri77]

I'm also looking for the same solution. if you have already find out the way to write your own application using TWAIN, please post it here, so that we can also use it.

[^NyAw^]

Hi,

I have no much time to explain how I make it works. Cut here, paste there, ... I need it for a commercial application that only scans gray images.
The attached files have been modified.
Here is some explanation how to use it:

1) Declare a "QTwain" class pointer in your application and create a new QTwain instance in the FIRST code line of your MainWindow class using "this" as the parent.

QTwain* m_pqTwain = new QTwain(this);

QTwain* m_pqTwain = new QTwain(this);

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2)Redefine the method "showEvent(QShowEvent* event)" on your MainWindow class and there call "m_pqTwain->setParent(this)".

3)Redefine the method "winEvent(MSG* pMsg,long* result)" with this call "return(m_pqTwain->processMessage(*pMsg) == TRUE);

4)Now, here is the hack:
To enumerate the sources(Scanner devices) I use "m_pTwain->initTwain()" and "m_pTwain->enumerateSources()"
To scan an image I use "m_pTwain->ReleaseTwain()", and "m_pTwain->initTwain()" again. Select the selected source using "m_pTwain->selectSource(m_iScannerDeviceIndex)". Configure the Scan device using "m_pTwain->selectDepth(8)", "m_pTwain->selectResolutionX(200)", "m_pTwain->selectResolutionY(200)". Finally, start the capture using "m_pTwain->acquire()". Note that if I don't release the Twain dll every time I get a scan finished, the messages are lost(don't know where, maybe in the space, .. :-P)

5) Use a Timer to let the main application check every X seconds if the scanner has finished. You have to check the "m_pTwain->m_bFiEscaneig" that will be true if it have finished. Oops, before starting the capture you have to set it to false by hand.

6) connect the SIGNAL "emetreImatge(QImage)" to your SLOT to get the image.

I know that is not a good solution to use but it works for my purpose. I hope anyone can hack it a little bit and let other people use it. It's not well documented and also, the comments and my defined variables will be in Catalan language(a language used into a region of Spain that includes Barcelona).

[jokinb]

Perdona Nyaw, pero al bajarme los dos ficheros qtwain.zip y QtTwainScan.zip e intentarlos abrir se produce un error: "Final inesperado del archivo".
Como estoy interesado en poder añadir capacidades para escanear a una aplicación que estoy haciendo, podrÃ*as facilitarnos esos archivos correctamente.

¿Has hecho algún progreso al respecto?

Muchas gracias.

[^NyAw^]

Hi,

Dear jokinb,
Don't post spanish posts on this forum as people can't read it.
I just downloaded the file and uncopressed using WinRAR and it had no error.
Respect to the progress on this, I said that it works not very well but it is perfect fot my application.
Maybe the newest 2 version of TWAIN will be better.
Of course you can send me private messages written in spanish.

[jokinb]

I will write in English.
I have domnloaded the qtwain.zip file and I have got the same error. "Unexpected end of archive".

It is posible to use the WIA tecnology in Qt?
Thanks
Jokinb

[^NyAw^]

Hi,

Try this, I only donwloaded the file from this forum uncompressed and compressed again.

[jokinb]

Finally , with a lot of tricks I have got the qtwain file downloaded.
How many files are in. I get six. It is ok.?

Thanks
Jokinb

[^NyAw^]

Hi,

Yes, there are 6 files.

I don't understand why you have to use a lot of tricks. Is there any other person that can try downloading the file and decompress it to check if there is any error on uncompress it?

[srsr]

I will write in English.
I have domnloaded the qtwain.zip file and I have got the same error. "Unexpected end of archive".

It is posible to use the WIA tecnology in Qt?
Thanks
Jokinb

and

YES it is possible to use WIA technology with Qt. It's even necessary with Windows10.
Just start with Windows SDK sample code :for example fiScanner

SRSR

[armad]

Hi, I would like to know you solved this problem? if yes please share with me, I'm just starting to learn Qt and this has become a problem for me. thank you in advance

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Added after 39 minutes:

Hi, I would like to know you solved this problem? if yes please share with me, I'm just starting to learn Qt and this has become a problem for me. thank you in advance