Dynamic .NET TWAIN FAQ

Questions

General Questions

Distribution Questions

Programming Questions

Answers

General Questions

1. What is TWAIN?

TWAIN is a protocol and Application Programming Interface (API) that standardizes communication between an application and image acquisition devices such as scanners and digital cameras. This standard allows a developer to make standard calls to any image acquisition device that supports TWAIN. Thus the application would not have to be rewritten to support every device. TWAIN has been in existence since 1992 and is governed by the TWAIN Working Group.

2. What is Dynamic .NET TWAIN?

Dynamic .NET TWAIN is a .NET component which enables you to acquire images from any TWAIN compatible devices. It is specially designed for Microsoft .NET Framework-based desktop scanning applications. It enables you to acquire images from any TWAIN compatible devices.

With the carefully designed interface, and the built-in wizard mode, Dynamic .NET TWAIN is very easy to use. You can typically do your TWAIN job in several lines of code. At the same time, Dynamic .NET TWAIN is very powerful. It is compatible with TWAIN specification V1.9. It supports all three image transfer modes and many other features.

3. For which purposes can I use Dynamic .NET TWAIN?

Dynamic .NET TWAIN is designed for Microsoft .NET Framework-based desktop scanning applications. It can be used for controlling any work of scanners, digital cameras and any other devices which support TWAIN standard. Dynamic .NET TWAIN can upload and download images through FTP(S) or HTTP(S) protocol. Proxy is supported.

4. Who do I contact if I need technical support?

We provide at least 20 hours Live Support per weekday. Live Support is an online chat service for our customers to interact with our support professional in real time.
You can email our support team. Our email address for Dynamic .NET TWAIN is NetTwain@dynamsoft.com.

5. I would like to request some features in the next version of Dynamic .NET TWAIN. Where do I make these requests?

If you have any requirement, please contact us by email. Your any request is very important to us. Please email to NetTwain@dynamsoft.com.

6. I have problems. What should I do?

The information on most of questions can be found in the documentation or in this FAQ.
Write to our support team to get more help. Our email address of support team is NetTwain@dynamsoft.com.

7. What is Live Help?

Dynamsoft is committed to providing the best customer support in the industry. Our support team is ready to offer no time limit, high quality, friendly and responsively technical support for our valued registered users.

We provide at least 20 hours Live Support per weekday. Live Support is an online chat service for our customers to interact with our support professional in real time.

Recognizing our world wide customers locate in different time zones, we proudly provide at least 20 hours Live Chat Support (Live Help) each day from Monday to Friday.
If you visit between Monday and Friday, and happen to see our Live Help support professional is offline, please wait a moment and our support professional will be with you shortly.
When the Live Help support professional is offline, you can also leave a message and we would response promptly.

8. Do you provide sample code? If yes, how can I get it?

Yes, we provide sample code of Dynamic .NET TWAIN in VB.NET and C#. You can find the samples in program group of Dynamic .NET TWAIN after installation.

9. What operating systems does Dynamic .NET TWAIN work with?

Dynamic .NET TWAIN supports Windows 95, 98, ME, NT, XP, 2000, 2003, Vista, 2008 and Windows 7.

10. What programming languages does Dynamic .NET TWAIN work with?

Dynamic .NET TWAIN can be used with C# and VB.NET.

Distribution Questions:

1. How do I distribute my application?

Runtime distribution is royalty free.

Only DynamicDotNetTwain.dll is distributable with end user application. All other files and documentations can NOT be distributed. YOU MUST NOT DISTRIBUTE ".LIC" FILE OF Dynamic .NET TWAIN.

Dynamic .NET TWAIN is very easy to distribute. You only need to distribute DynamicDotNetTwain.dll with your desktop applications. The DLL file does not need to be registered.

2. What files I need to include in the setup package of my program?

You need DynamicDotNetTwain.dll in the setup package only.

Programming Questions

1. How can I acquire black-white images?

Twain1.OpenSource();
Twain1.IfShowUI = false;
Twain1.IfDisableSourceAfterAcquire = true;
Twain1.PixelType = Dynamsoft.DotNet.TWAIN.Enums.TWICapPixelType.TWPT_BW;
Twain1.AcquireImage();

2. How can I work without User Interface?

private void BeginScan()
{
    Twain1.OpenSource();
    Twain1.IfShowUI = false; // set without user interface
    Twain1.IfDisableSourceAfterAcquire = true;

    Twain1.AcquireImage();
}


private void Twain1_OnPostTransfer()
{
    Twain1.SaveAsBMP("c:\temp.bmp", 0);
}

3. How can I scan only a part of a picture?

Twain1.SelectSource();
Twain1.OpenSource();
Twain1.IfShowUI = false;


// Set Image Layout
Twain1.Unit = Dynamsoft.DotNet.TWAIN.Enums.TWICapUNits.TWUN_INCHES; // INCHES
Twain1.SetImageLayout(0, 0, 5, 5);

Twain1.AcquireImage();

4. How can I select necessary device without device selection dialog?

Twain1.OpenSourceManager();

int count = Twain1.SourceCount;

for (short lngNum = 0; lngNum < count; lngNum ++)
{
    if (Twain1.SourceNameItems(lngNum) == "Specified device name")
    {
        Twain1.SelectSourceByIndex (lngNum);
        break;
    }
}

// if can't find the specified source, it'll select default source
Twain1.AcquireImage();

5. How can I disable progress indicator dialog when I acquire images without UI?

Twain1.IfShowUI = false;
Twain1.IfDisableSourceAfterAcquire = true;

Twain1.OpenSource();
Twain1.IfShowIndicator = false;
Twain1.AcquireImage();

6. How can I set resolution in the X and Y direction separately?

Twain1.SelectSource();
Twain1.OpenSource();

//Set XRESOLUTION current value.
Twain1.Capability = Dynamsoft.DotNet.TWAIN.Enums.TWCapability.ICAP_XRESOLUTION;
Twain1.CapType = Dynamsoft.DotNet.TWAIN.Enums.TWCapType.TWON_ONEVALUE;
Twain1.CapValue = 300;
if (Twain1.CapSet() == false)
    MessageBox.Show("Failed to set the x-resolution.\r\n" + Twain1.ErrorString);

//Set YRESOLUTION current value.
Twain1.Capability = Dynamsoft.DotNet.TWAIN.Enums.TWCapability.ICAP_YRESOLUTION;
Twain1.CapType = Dynamsoft.DotNet.TWAIN.Enums.TWCapType.TWON_ONEVALUE;
Twain1.CapValue = 200;
if (Twain1.CapSet() == false)
    MessageBox.Show("Failed to set the y-resolution.\r\n" + Twain1.ErrorString);

Twain1.AcquireImage();

7. How can I upload acquired image to the Web server?

Dynamic .NET TWAIN supports FTP, HTTP Put and HTTP Post upload method.

The following is a http put method sample:

private void BeginScan()
{
    Twain1.AcquireImage();
}

private void Twain1_OnPostTransfer()
{
	if (Twain1.HTTPUploadThroughPut("127.0.0.1", 0, "httpUploadFileTemp.bmp") == false)
		MessageBox.Show(Twain1.ErrorString);
}

8. How to use ADF? We want to save each document in a separate file.

int iDocumentCounter = 0;
private void ADFScan()
{
    iDocumentCounter = 0;  //set initialize value

    Twain1.OpenSource();

    Twain1.IfShowUI = false;
    Twain1.IfDisableSourceAfterAcquire = true;
    if (Twain1.Duplex != Dynamsoft.DotNet.TWAIN.Enums.TWICapDuplex.TWDX_NONE)
        Twain1.IfDuplexEnabled = true; //enable duplex

    if (Twain1.IfFeederEnabled)
    {
        Twain1.XferCount = -1;
        Twain1.IfAutoFeed = true; //auto feed 

        if (Twain1.IfFeederLoaded)
            Twain1.AcquireImage();
    }
}

private void Twain1_OnPostTransfer()
{
    iDocumentCounter = iDocumentCounter + 1;

    if (!Twain1.SaveAsBMP(@"c:\" + iDocumentCounter.ToString() + ".bmp", 0))
            MessageBox.Show(Twain1.ErrorString);
}

9. How can I work with SSL?

You can use the IfSSL property.

Twain1.HTTPPort = 80; 
Twain1.IfSSL = false; // if 80 is the port number of non-secure port


/* 
Twain1.HTTPPort = 443; 
Twain1.IfSSL = true; // if 443 is the port number of secure port
*/


Twain1.HTTPUploadThroughPost("127.0.0.1", 0, "/SaveToFile.php", "imageData.jpg");

if (Twain1.ErrorCode != Dynamsoft.DotNet.TWAIN.Enums.ErrorCode.Succeed)
    MessageBox.Show(Twain1.ErrorString);
else //succeded
    MessageBox.Show("Successful");

10. How can I add a new scanned image to an existed multi-page TIFF file?

private void Scan()
{
    Twain1.AcquireImage();
}
        
private void Twain1_OnPostTransfer()
{
    Twain1.CloseSource();

    Twain1.IfTiffMultiPage = true;
    Twain1.SaveAsTIFF (@"C:\SaveAsTIFF.tif", 0);

    if (Twain1.ErrorCode != Dynamsoft.DotNet.TWAIN.Enums.ErrorCode.Succeed)
        MessageBox.Show(Twain1.ErrorString);
    else 
        MessageBox.Show("Successful");
}

11. How can I rotate an image before I save it?

You can use the RotateLeft property and the RotateRight property.

private void Scan()
{
    Twain1.AcquireImage();
}

private void RotateLeft()
{
    Twain1.RotateLeft(0);
}

private void RotateRight()
{
    Twain1.RotateRight(0);
}

private void Rotate()
{
    Twain1.Rotate(0, 45.0, true, Dynamsoft.DotNet.TWAIN.Enums.DWTInterpolationMethod.Bicubic);
}

Also, you can use the ShowImageEditor method.

private void Scan()
{
    Twain1.AcquireImage();
}

private void Twain1_OnPostTransfer()
{
    Twain1.CloseSource();

    Twain1.ShowImageEditor();
	// You need to save the rotated image in the image editor before closing it    
}

12. How can I view a specified image if there are several images in buffer?

You can view a specified image or go through all the images in buffer with clicking "NextImage" or "PreImage" buttons.

private void Next()
{
    if (Twain1.HowManyImagesInBuffer == 0)
        MessageBox.Show("There is no image in buffer");

    Twain1.CurrentImageIndexInBuffer = (short)(Twain1.CurrentImageIndexInBuffer + 1);
}

private void Previous()
{
    if (Twain1.HowManyImagesInBuffer == 0)
        MessageBox.Show("There is no image in buffer");

    Twain1.CurrentImageIndexInBuffer = (short)(Twain1.CurrentImageIndexInBuffer - 1);
}

13. How can I do a duplex scan?

private void DuplexScan()
{
    Twain1.SelectSource();
    Twain1.OpenSource();

    Twain1.IfDuplexEnabled = true; //enable duplex
    Twain1.XferCount = 2;
    Twain1.MaxImagesInBuffer = 2;

    Twain1.AcquireImage();
}

14. How can I scan an inverted image?

You can use the PixelFlavor property.

private void Scan()
{
    Twain1.PixelFlavor = Dynamsoft.DotNet.TWAIN.Enums.TWICapPixelFlavor.TWPF_CHOCOLATE;
    Twain1.AcquireImage();
}