1. Introduction.................................................................................................................. 1

2. Features........................................................................................................................ 1

3. Software Requirements............................................................................................ 2

4. ObjectTWAIN™ ActiveX Library OCX Installation.................................................... 3

5. Start Example............................................................................................................... 4

6. Programming Guide..................................................................................................... 6

6.1. ObjectTWAIN™ Acquisition Session States....................................................... 6

6.2. How To Handle Error Conditions....................................................................... 8

6.2.1. General Rules......................................................................................................................................... 8

6.2.2. Handling ObjectTWAIN™ Operation Errors....................................................................................... 8

6.2.2.1. OLE Exceptions.................................................................................................................................... 8

6.2.2.2. The GetLastError method................................................................................................................ 10

6.3. How To Select a Data Source and Open a TWAIN Session........................... 11

6.3.1. Select and use the default TWAIN Data Source....................................................... 11

6.3.2. Select and use a custom, fixed TWAIN Data Source................................................ 11

6.3.3. Use a custom select source dialog......................................................................... 12

6.4. How To Negotiate Capabilities........................................................................... 13

6.4.1. How to iterate through an enumeration, array or range of capability values.................. 14

6.4.1.1. Arrays and Enumerations of values............................................................................................... 14

6.4.1.2. Ranges of values.............................................................................................................................. 14

6.4.1.3. Example how to get the capabilities reported as supported by the Data Source................. 15

6.4.1.4. Example how to get the x-axis resolution values supported by the Data Source................. 17

6.4.2. How to set to Data Source an enumeration or array of capability values...................... 20

6.4.2.1. Use a TWContainer object returned by a GetAvailable or Get operation................................ 20

6.4.2.2. Use a new TWContainer object...................................................................................................... 20

6.5. How To Negotiate the Acquisition Frame Layout.......................................... 22

6.5.1.1. Visual Basic example....................................................................................................................... 22

6.5.1.2. Delphi 4 example.............................................................................................................................. 23

6.5.1.3. PowerBuilder example..................................................................................................................... 24

6.6. How To Start the Image Acquisition................................................................. 25

6.7. How To Handle Transferred Image Data and Other Transfer Events.... 26

6.8. How To Get Image Information.......................................................................... 29

6.9. How To Get Extended Image Information........................................................ 30

6.10. How To Use the Automatic Document Feeder............................................... 33

7. Library Reference..................................................................................................... 34

R.1. ObjectTWAIN™ ActiveX/COM Controls.............................................................. 34

R.2. Other ObjectTWAIN™ COM Controls................................................................ 35

R.3. TWControl ActiveX Control Properties......................................................... 37

R.4. TWControl ActiveX Control Basic Methods................................................... 39

R.5. TWControl ActiveX Control Defined Capability Methods........................... 46

R.6. TWControl ActiveX Events................................................................................. 63

R.6. Other ObjectTWAIN™ COM Objects Interfaces.............................................. 64

R.7. ObjectTWAIN™ COM Constant Enumerations.................................................. 66

5. Start Example

This chapter describes the steps to develop a minimal ObjectTWAIN™ application in Visual Basic Version 6.0 to select a TWAIN Data Source and to acquire and display one image from it.

Step 1: Start Visual Basic. Choose New Project | Standard EXE. A project named Project1 with one form called Form1 will be displayed.

Step 2: Select Project | Components and check the component called Object TWAIN ActiveX Library. If this component is not listed here this means that it was not correctly installed. Refer to the Install section about how to install and register the ObjectTWAIN™ ActiveX for design and development purposes.

The control shall be listed in the Toolbox list of controls (if this is not visible, select View | Toolbox) with the name TWControl and the following bitmap:

Step 3: Select the control and drag it on the form. A new control called TWControl1 will be created. In the properties window make sure that the NativeMemoryAsFile property is enabled, the NativeMemoryFileType property is set to 2 – DIB and the Quiet property is disabled.

Step 4: Add a CommandButton (named Command1) and set its caption to “&Select Source”. Double-click the button and add the following code to display the TWAIN Data Source Manager Select Source dialog:

Private Sub Command1_Click()

On Error GoTo errSelectSource

TWControl1.UserSelectSource

Exit Sub

errSelectSource:

MsgBox "Error on Select Source or cancel pressed"

End Sub

Step 5: Add another CommandButton (named Command2) and set its caption to “&Acquire”. Double click this newly added button and add the following code to open a TWAIN session with the selected Data Source and start the image acquisition. The code also sets the current value of the CAP_XFERCOUNT capability to 1 (meaning that the application is willing to transfer one image in one TWAIN session) by calling TWControl1.SetXferCount. The transfer mode used is Native. Because the TWControl.NativeMemoryAsFile property is enabled (set to True) the memory Native DIB image will be saved by ObjectTWAIN™ to a disk file. The acquisition will be done with the Data Source User Interface displayed (the parameter of StartNativeAcquisition):

Private Sub Command2_Click()

On Error GoTo errAcquire

TWControl1.OpenSession hWnd

TWControl1.SetXferCount 1

TWControl1.StartNativeAcquisition True

Exit Sub

errSelectSource:

MsgBox Err.Description

TWControl1.CloseSession

End Sub

Step 6: Add a PictureBox control, named Picture1. This PictureBox control will be used to display the acquired image.

Step 7: Double-click the TWControl1 control and add the following code to receive the transferred image from the Data Source and display it using the PictureBox control. The acquisition will be stopped after one image transfer is completed: if the Data Source will have more images available for transfer the application (in this example) will not continue to transfer the next image:

Private Sub TWControl1_DoProcessNativeAsFileData(ByVal FileFormat As OBJTWAINLibCtl.tagImageFileFormat, ByVal FileName As String)

On Error GoTo errProcessData

Picture1.Picture = LoadPicture(FileName)

TWControl1.StopAcquisition

Exit Sub

errProcessData:

MsgBox Err.Description

TWControl1.StopAcquisition

End Sub

Step 8: Double-click the TWControl1 control and add the following code to handle special transfer conditions that may appear: the user may close the Data Source UI without initiating an image transfer, the Data Source may fail the transfer because of an acquisition hardware problem or the user may simply cancel the transfer while processing. All the transferred data and transfer error notifications are signaled by ObjectTWAIN™ as ActiveX events:

Private Sub TWControl1_OnCancelTransfer()

MsgBox "Transfer canceled"

TWControl1.CloseSession

End Sub

Private Sub TWControl1_OnEndTransfers()

TWControl1.CloseSession

End Sub

Private Sub TWControl1_OnTransferError(ByVal Error As OBJTWAINLibCtl.tagObjectTwainError, ByVal ErrorDescription As String)

MsgBox ErrorDescription

TWControl1.StopAcquisition

End Sub

Private Sub TWControl1_OnUserCloseSourceUI(ByVal CloseOK As Boolean)

MsgBox "Source UI closed"

TWControl1.CloseSession

End Sub

Step 9: Save and run the EXE application. Press Select Source to display the DSM dialog and select a Data Source. This will be the default TWAIN Data Source in the system and will be preserved across multiple TWAIN sessions until a new Source is installed or set as default. Press Acquire to start the TWAIN acquisition and transfer one image to the application. Make sure you start the scan from the Data Source User Interface: because the Data Source UI is displayed, the ‘Transfer Ready’ signal will be not triggered automatically by the Data Source.

6. Programming Guide

6.1. ObjectTWAIN™ Acquisition Session States

TWAIN describes seven states that exist in TWAIN sessions. ObjectTWAIN™ provides a simplified model described by only four states. The following table lists the ObjectTWAIN™ states, the relation with the TWAIN states and how the application may cause a state transition:

ObjectTWAIN™ State	TWAIN State(s)	ObjectTWAIN™ State Transition
0- ObjectTWAIN™ not started	1 - DSM not loaded	TO NEXT STATE: Transition to next state when a TWControl is created at run time (e.g. when the form containing the control is created).
1- ObjectTWAIN™ started TO DO: In this state the application may enumerate the available Data Sources, get Data Source information and/or select a Data Source. RESTRICTIONS: In this state the application cannot do state any capability negotiation or request to start acquisition since no Data Source is yet loaded and opened.	2 - DSM loaded 3 - DSM opened	TO NEXT STATE: Transition to next state when a session with a Data Source is opened (when OpenSession is successfully executed). TO PREVIOUS STATE: Transition to previous state when the current instance of TWControl is destroyed.
2 – Source Session opened TO DO: In this state the application may do capability negotiation (see if a capability is supported, get/set capability values) and negotiate the image layout frame. Note: A single ObjectTWAIN™ application may open and manage multiple Source sessions simultaneously by using multiple TWControl instances.	4 - Source opened	TO NEXT STATE: Transition to next state when the ObjectTWAIN™ acquisition is started (e.g. one of the TWControl StartXAcquisition methods is executed). TO PREVIOUS STATE: Transition to previous state when the current Source Session is closed (after CloseSession is executed).

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ObjectTWAIN™ State

TWAIN State(s)

ObjectTWAIN™ State Transition

3 – Acquisition

TO DO:

In this state the application may wait to receive image data transferred from the Source and/or to be notified about special conditions that may appear during the acquisition sequence. Also the application may request non-image data (e.g. barcode data) after a transfer, ask information about the next image to be transferred and continue or stop the acquisition.

Note: CloseSession may be called at any time: if the acquisition is started it will first stop the acquisition then close the session.

RESTRICTIONS:

In this state the Application may not request to change any capability value unless that capability was negotiated in the previous state as extended (through Get/ SetExtendedCaps).

5 - Source enabled

6 - Transfer ready

7 – Transferring data

TO PREVIOUS STATE:

Transition to previous state when the acquisition sequence is interrupted (by executing StopAcquisition) or when all the available images are transferred to application.

All TWAIN operations (including Capability operations) are exposed by ObjectTWAIN™ ActiveX Library as methods of an invisible at run-time ActiveX control called TWControl. The transferred image data and the transfer errors and special conditions are signaled through TWControl ActiveX events. The ObjectTWAIN™ ActiveX Library also exposes other COM objects to wrap various TWAIN data structures (e.g. TWContainer which provides access to TWAIN TW_CAPABILITY data and capability containers such as TW_ARRAY). All COM objects exported by the Library may be accessed as OLE Automation objects.

In the next sections the basic application operation procedures will be explained (in the order that may appear in an ObjectTWAIN™ session). Some of the techniques described will be accompanied by code examples in Visual Basic or other programming languages.

6.2. How To Handle Error Conditions

The big part of the TWAIN API is described by the TWAIN Specification to be only optional to be implemented by Data Sources. Worst, there are few Data Sources which really correctly support correctly the minimal set of mandatory TWAIN operations and capabilities. A well designed TWAIN application must be able to identify and handle any kind of error which has occurred in a TWAIN session, and gracefully manage the session with any Data Source.

6.2.1. General Rules

· The application may try to use any kind of optional TWAIN functionality but the application shall not rely on such optional TWAIN functionality to succeed and be able to transfer images from a Data Source. If the Data Source does not support an optional Transfer Mode simply switch to another mode instead of terminating the session prematurely.

· Always check the result of a TWAIN operation: all TWControl methods mapped to TWAIN operations may provide two different error result handling mechanisms (see below).

· It is recommended before using a capability to check if the capability is reported as supported (through GetSupportedCaps). Also, before trying to set a capability value get the values the Data Source supports for that capability. Do not assume that the Data Source will preserve current capability values across sessions.

· The application may interrupt the current acquisition sequence at any time by calling TWControl.StopAcquisition. After this the application may try to start other acquisition sequence (by optionally adjusting capability values and calling one of the TWControl.StartXAcquisition methods) or terminate the entire TWAIN session (by calling TWControl.CloseSession). It is important to know that CloseSession may be called at any time to terminate the current session: it even calls StopAcquisition automatically if needed. If no session is opened at the time CloseSession is called nothing happens.

6.2.2. Handling ObjectTWAIN™ Operation Errors

An application may retrieve the result of a TWControl method in two different modes:

· Handling OLE Exceptions;

· Using the TWControl.GetLastError method.

Each of these two methods is explained in one of the following sub-sections:

6.2.2.1. OLE Exceptions

When an error is encountered ObjectTWAIN™ (if configured appropriately) throws an exception object. The application may handle such an exception by having a try-catch exception-handling block around the failed operation call.

If the application does not handle one exception in its code, it is the default exception handler for the application that will handle this exception: usually this will display a message to the user and terminate the application. While such a behavior (to exit the application at the first TWAIN error encountered) may be useful in the beginning of the application development phase it shall not be used on purpose in the final version of the application: any attempt to get an unsupported capability or to set an unsupported capability value will cause an exception and will terminate the entire application instead of continuing the session and simply consider that capability or value as unsupported by the Data Source.

The major advantage of this method is its simplicity: the application may provide a single error-handling block for an entire sequence of TWAIN operations. The drawback would be that an exception will be thrown for every error encountered, the application will be unable to choose to continue for non-fatal errors like the one caused when the user closes the DSM Select Source dialog by pressing cancel. Using the second error handling method the application may decide for which error codes to prompt the user or execute special error action.

To use this mechanism the TWControl Quiet property must be disabled (set to False), either at design or run-time.

The following examples show how to provide a handler for an error passed by ObjectTWAIN™ as an OLE exception (the TWControl.SetFeederEnabled and SetAutoFeed methods will be used):

Visual Basic example:

Private Sub SetFeederBtn_Click()

On Error GoTo errSetFeeder

If TWControl.GetState <> OPENED Then

MsgBox "No session opened"

Exit Sub

End If

TWControl.SetFeederEnabled True

TWControl.SetAutoFeed True

Exit Sub

errSetFeeder:

MsgBox Err.Description

End Sub

Delphi 3 example:

try

TWControl.SetFeederEnabled(True);

TWControl.SetAutoFeed(True);

except

Application.MessageBox('SetADF Error', 'Scan', MB_YESNO)

end;

Visual C++ example:

try

{

m_twControl.SetFeederEnabled(TRUE);

m_twControl.SetAutoFeed(TRUE);

}

catch(COleDispatchException *error)

{

AfxMessageBox(error->m_strDescription);

}

6.2.2.2. The GetLastError method

ObjectTWAIN™ provides an alternate method to retrieve result codes by using a special TWControl method named GetLastError. This method will return the status of the last TWAIN operation executed. This method may be especially useful when the application development environment or programming language does not support an exception handling mechanism.

To use this mechanism the TWControl Quiet property must be enabled (set to True), either at design or run-time. When the Quiet property is enabled, ObjectTWAIN™ does not throw an OLE exception when an error is encountered.

Visual Basic example:

TWControl.SetFeederEnabled True

If OBJTWAIN_NO_ERROR <> TWControl.GetLastError Then

MsgBox "SetFeederEnabled failed"

End If

Delphi 3 example:

//TWError : tagObjectTwainError;

TWControl1.SetFeederEnabled(True);

TWError := TWControl.GetLastError();

if TWError <> OBJTWAIN_NO_ERROR then

Application.MessageBox('SetFeederEnabled failed',

'Error', MB_ICONSTOP)

PowerBuilder example:

integer result = 0

this.object.SetFeederEnabled(True)

result = this.object.GetLastError

if (512 <> result) then //512 is OBJTWAIN_NO_ERROR

MessageBox("SetFeederEnabled failed", "Error")

end if

Note:

You may see the values defined by ObjectTwainError in the “ObjectTWAIN™ COM Constant Enumerations” reference section at the end of the document.

6.3. How To Select a Data Source and Open a TWAIN Session

6.3.1. Select and use the default TWAIN Data Source

This is the most simple to implement and the most robust mechanism to select and open a session with a Data Source. This technique adheres to the model recommended in the TWAIN Specification. Usually an application will have two User Interface command elements (e.g. menu items or buttons), one to select the default source and another one to open the default source and start the acquisition.

Use the TWControl UserSelectSource method to display the default Source Select dialog and let the user to select the default TWAIN Data Source. This default will be preserved across TWAIN sessions until a new Data Source is installed on the system or another default is selected.

Use the TWControl OpenSession method to open a session with the default Data Source.

Visual Basic example:

TWControl.OpenSession Form1.hWnd

Delphi example:

TWControl.OpenSession(Application.Handle, '');

Visual C++/MFC example:

m_twControl.OpenSession((long)m_hWnd, _T(""));

6.3.2. Select and use a custom, fixed TWAIN Data Source

This may be useful for a special purpose application that may need to be dedicated to only one acquisition device. The second parameter of OpenSession may be used to pass as a character string the name of the Data Source to open. This is the same string listed in the Select Source dialog and it corresponds to the TW_IDENTITY.ProductName reported by the Data Source.

Visual Basic example:

TWControl.OpenSession Form1.hWnd, "ScanPartner 15C"

6.3.3. Use a custom select source dialog

ObjectTWAIN™ ActiveX Library exports two COM objects useful in this situation: TWSourceInfo (a wrapper object for the TWAIN TW_IDENTITY structure) and TWSourceList (a collection of TWSourceInfo objects). The TWControl GetInstalledSources method may be used to get the list of installed Data Sources information as a TWSourceList object.

First you have to display to the user the names of the Data Sources to select one from. You may display the names for all the Data Source installed or select a subset of the available Data Sources (based on the information contained by the TWSourceInfo object for each Data Source found).

Visual Basic example: how to fill a ListBox object (List1) with the names of all TWAIN Data Sources installed on the system:

Dim SourceList As TWSourceList

Dim SourceInfo As TWSourceInfo

Set SourceList = TWControl.GetInstalledSources

For Each SourceInfo In SourceList

List1.AddItem SourceInfo.ProductName

Set SourceList = Nothing

Then, to open the selected Data Source, call the TWControl OpenSession method passing the selected Source name as the second parameter:

Private Sub SelectBtn_Click()

TWControl.OpenSession hWnd, List1.List(List1.ListIndex)

End Sub

6.4. How To Negotiate Capabilities

ObjectTWAIN™ provides access to any possible capability operation (Get, GetCurrent, GetDefault, Reset, Set, QuerySupport) on any capability, either defined by TWAIN or custom defined, through TWControl methods and the TWContainer COM object. TWContainer is a wrapper object for capability containers (arrays, enumerations and range of values). Where possible, simple types are used (such as integer, boolean or string). In all other cases, a reference to a TWContainer object will be passed to a Set function or returned by a Get operation.

IMPORTANT:

· Do not assume that any Data Source will support a capability (even though this would be a capability described by the TWAIN Spec to be mandatory to be supported by any Data Source). Always check for error codes signaling an unsupported capability, operation on capability or even a general failure caused by an unexpected problem into the Data Source.

· It is recommended to always check the TWContainer objects (returned by Get/ GetAvailable/ GetCurrent/ GetDefault and Reset operations) to be valid (the VARIANT/ANY variable received needs to be a valid reference to a TWContainer COM object) and the type of container (TWContainer.Type may be ON_RANGE, ON_ENUMERATION or ON_ARRAY) before trying to read the container values (this is specially important when negotiating capabilities that may accept multiple container types).

· It is recommended to check first if a capability is supported (by using GetSupportedCaps), get the available/supported values (by using the GetAvailable or Get method related to that capability) and only then try to change (set) the current or available set of values for that capability. By isolating a problem in the Data Source the application may avoid using a badly implemented Data Source feature that may cause the entire application to hang or crash.

· Do not try to set a capability after the acquisition has been started unless that capability was previously negotiated as extended (through TWControl.Get/SetExtendedCaps). Also make sure a Data Source Session is opened before executing any capability operation.

The next sub-sections will describe some of the most frequent cases of capability negotiation.

6.4.1. How to iterate through an enumeration, array or range of capability values

All GetAvailable on enumerated and range type capabilities (e.g. ICAP_PIXELTYPE, ICAP_XRESOLUTION) or Get on array-type capabilities (e.g. CAP_EXTENDEDCAPS) TWControl methods return when successful a reference to a TWContainer COM object ‘filled’ with the array, enumeration or range of capability values returned by the Data Source as result to the TWAIN capability operation requested.

6.4.1.1. Arrays and Enumerations of values

There are two possible methods of iterating the values from an enumeration or array of values contained by a TWContainer object:

· Use the automatic OLE Collection iteration feature. This method is currently supported only by the most recent versions of Visual Basic through the for each statement.

· Iterate the values by using the special designed methods exposed by TWContainer: Count() to get the number of items in container and Item(Index) to retrieve an item at the given index. These methods shall be accessible from any programming environment able to understand standard OLE Automation interfaces (all the COM interfaces exposed by ObjectTWAIN™ objects are dual interfaces).

Notes:

· All indexes for objects exposed by ObjecTWAIN ActiveX Library are 1-based in Visual Basic style: the index of the first item in a list is 1 (not 0).

· A TWContainer object is actually a collection of VARIANT objects: a VARIANT element may be of any possible type, from a boolean value to a reference to a complex COM object expressed as a pointer to an IDispatch interface. For capability operations the most ‘complex’ COM object that may be (under normal conditions) contained by a TWContainer is a TWFrame object (object used for GetAvailable/GetCurrent/GetDefault/Reset/SetIFrames).

To access the current and/or the default value in a TWContainer enumeration an enumeration TWContainer object exposes the CurrentIndex and DefaultIndex properties.

6.4.1.2. Ranges of values

The TWContainer objects expose a set of properties to enable an application to access them as ranges of values: RangeMin, RangeMax, RangeStep, RangeCurrent and RangeDefault (when the container type is ON_RANGE).

6.4.1.3. Example how to get the capabilities reported as supported by the Data Source

The application may use TWControl GetSupportedCaps method to ask the Data Source to return an array of the supported capabilities. GetSupportedCaps will return the array as a TWContainer collection of TWCapabilityName objects or simple integer values (depending how the collection is accessed, as a collection of objects or integers):

Visual Basic example (no error checking code; the ‘for each’ approach is used):

Dim Caps As TWContainer

Dim Capability As TWCapabilityName

Set Caps = TWControl.GetSupportedCaps

For Each Capability In Caps

‘ do something, e.g.:

If Capability = IC_ORIENTATION Then

bSupportsOrientation = True

Exit For

End If

Set Caps = Nothing

Delphi 3 example (no error checking code; the Count/Item(Index) approach is used):

//SupportedCapsCon : OleVariant;

//SourceSupportsOrientation : Boolean;

//i : Integer;

SupportedCapsCon := TWControl.GetSupportedCaps;

for i := 1 to SupportedCapsCon.Count do

begin

// do something, e.g.:

if SupportedCapsCon.Item[i].Value = IC_ORIENTATION then

bSupportsOrientation := True;

end;

endSupportedCapsCon := UnAssigned;

Note:

In this case the items in the TWContainer object are references to TWCapabilityName COM objects. In the first example it was not needed to explicitly use the TWCapabilityName.Value property, Visual Basic was smart enough to automatically convert the integer value to the default property of the TWCapabilityName object. The second example shows how to explicitly use this property when the programming environment is not able to automatically make the conversion.

Visual C++ example:

BOOL bIcapOrientationSupported = FALSE;

try

{

VARIANT varSupportedCaps = m_twControl.GetCapSupportedCaps();

// Proceed only if received a valid pointer to a Dispatch interface:

if((VT_DISPATCH == varSupportedCaps.vt) && (varSupportedCaps.pdispVal))

{

// Connect the received IDispatch to a TWContainer object:

ITWContainer SupportedCaps(varSupportedCaps.pdispVal);

// Iterate through the TWContainer and search for ICAP_ORIENTATION:

int nSupportedCaps = SupportedCaps.GetCount();

COleVariant varOrientationCapName((long)ICAP_ORIENTATION);

for(int i = 1; i <= nSupportedCaps; i++)

{

COleVariant varCapabilityName = SupportedCaps.GetItem(i);

// Make sure that we compare here an integer value:

// (VT_I4 stands for '4 bytes signed integer)

// (the varCapabilityName may be an IDispatch to an

// TWCapabilityName object; in this case may be better

// to access directly this VARIANT as an integer)

varCapabilityName.ChangeType(VT_I4);

//if(ICAP_ORIENTATION == varCapabilityName.lVal)

if(varOrientationCapName == varCapabilityName)

{

bIcapOrientationSupported = TRUE;

break;

}

catch(COleDispatchException *)

{

// CAP_SUPPORTEDCAPS is not supported

}

6.4.1.4. Example how to get the x-axis resolution values supported by the Data Source

The application may use TWControl GetAvailableIXResolution method to ask the Data Source to return an enumeration or range of the supported x-axis resolutions. The range or enumeration of values will be returned by GetAvailableIXResolution as a TWContainer collection of floating point values (not integer because ICAP_XRESOLUTION values are defined by TWAIN as TW_FIX32). If the Data Source returns a TWON_ONEVALUE container ObjectTWAIN™ will make automatically an enumeration containing only one item which will also be the current and default one. The application will have to read the TWContainer Type property before trying to access the resolution values as an enumeration or as a range of values (TWAIN defines both container types to be allowed for DAT_CAPABILITY/ MSG_GET on ICAP_XRESOLUTION).

Visual Basic example (no error checking code):

Dim Xres As TWContainer

Set Xres = TWControl.GetAvailableIXResolution

If Xres.Type = ON_ENUMERATION Then

For Each Item In Xres

' do something: add the resolutions to a ListBox control

List1.AddItem Item

' read the current and default values:

MsgBox Xres(Xres.CurrentIndex), vbOKOnly, "Current x res"

MsgBox Xres(Xres.DefaultIndex), vbOKOnly, "Default x res"

Else

k = 0

Value = Xres.RangeMin + k * Xres.RangeStep

If Value > Xres.RangeMax Then

Exit Do

End If

List1.AddItem Value

k = k + 1

Loop

MsgBox Xres.RangeMin, vbOKOnly, "Min x res"

MsgBox Xres.RangeMax, vbOKOnly, "Max x res"

MsgBox Xres.RangeCurrent, vbOKOnly, "Current x res"

MsgBox Xres.RangeDefault, vbOKOnly, "Default x res"

End If

Delphi 3 example:

// XResCon : OleVariant;

// SourceSupportsXRes, NeedToSetXRes : Boolean;

// i : Integer;

// ConfigRes, rmin, rmax, rdef, rstep, rcur, f : Double;

// TWError : tagObjectTwainError;

// Check if the Data Source supports a ‘configured’ x-resolution

// and set it to be the current value for this session

// (if not already selected in the DS):

SourceSupportsXRes := False;

NeedToSetXRes := True;

try

XResCon := TWControl.GetAvailableIXResolution;

TWError := TWControl.GetLastError;

if TWError = OBJTWAIN_NO_ERROR then

begin

Assert(varDispatch = VarType(XResCon));

if XResCon.Type = ON_RANGE then

begin

// Check basically only if the configured value is in the

// requested range (no exact step coverage estimation)

if (XResCon.RangeMin <= ConfigRes) and

(XResCon.RangeMax >= ConfigRes) then

begin

SourceSupportsXRes := True;

if XResCon.RangeCurrent = ConfigRes then

begin

// No need to set XResolution

NeedToSetXRes := False;

end;

end

else

begin

SourceSupportsXRes := False;

// Configured XResolution outside available range

end;

end

else if XResCon.Type = ON_ENUMERATION then

begin

for i := 1 to XResCon.Count do

begin

if XResCon.Item[i] = ConfigRes then

begin

SourceSupportsXRes := True;

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(continued from previous page)

if i = XResCon.CurrentIndex then

begin

// XRes already set, no need to set again

NeedToSetXRes := False;

end;

break;

end;

if SourceSupportsXRes = True and NeedToSetXRes = True then

begin

TWControl.SetIXResolution(ConfigRes);

TWError := TWControl.GetLastError;

if TWError <> OBJTWAIN_NO_ERROR then

begin

SourceSupportsXRes := False;

end;

except

SourceSupportsXRes := False;

end;

6.4.2. How to set to Data Source an enumeration or array of capability values

It is recommended to use this technique when the application wants to try to limit the set of available values for an enumerated-type capability (e.g.: limit the pixel types supported by the Data Source in the current session only to B&W and Grayscale – if: (1) the Data Source supports TrueColor by default and the user can change the pixel type from the Data Source UI and (2) the application does not want to receive RGB image data and (3) the Source accepts the application’s request to exclude the RGB pixel type from its set of supported pixel types in this session, then the Data Source shall no longer let the user set RGB from its UI – e.g. by disabling the related button in its interface).

There are two different methods to get a TWContainer object to pass the enumeration of values to the Data Source:

6.4.2.1. Use a TWContainer object returned by a GetAvailable or Get operation

Visual Basic example (no error checking code): get the pixel types supported by the Data Source, then remove RGB if present from the enumeration and set it back to the Data Source:

Dim PixelTypes As TWContainer

Dim pt As TWPixelTypeValue

Set PixelTypes = TWControl.GetAvailableIPixelType

i = 1

LimitedRGB = False

For Each pt In PixelTypes

If pt = PT_RGB Then

PixelTypes.Remove i

LimitedRGB = True

Exit For

End If

i = i + 1

If LimitedRGB Then

TWControl.SetIPixelType PixelTypes

End If

Set PixelTypes = Nothing

6.4.2.2. Use a new TWContainer object

The only special thing here is that the application has to construct a new COM object, in this case TWContainer:

Step 1: Construct a new TWContainer object

Visual Basic example:

Dim NewPixelTypes As New TWContainer

Delphi example:

NewPixelTypes := CoTWContainer.Create;

PowerBuilder example:

OLEObject NewPixelTypes

integer result = 0

NewPixelTypes = CREATE OLEObject

if not IsNull(NewPixelTypes) then

result = NewPixelTypes.ConnectToNewObject("ObjTWAIN.TWContainer")

if 0 > result or IsNull(result) then

/* insert here error handling code */

else

/* initialize the new TWContainer */

end if

Step 2: Initialize the container type

Visual Basic example:

NewPixelTypes.InitEnumeration 2

Notes:

· In the above example 1 is the number of items in the new enumeration.

· To initialize an Array or Range use TWContainer.InitArray respectively InitRange.

Step 3: Add values to the container

Visual Basic example (no error checking code):

NewPixelTypes.Add PT_BW

NewPixelTypes.Add PT_GRAY

Step 4: Set to Data Source the container

Visual Basic example (no error checking code):

TWControl1.SetIPixelType NewPixelTypes

Step 5: When finished with the container object, destroy it

Visual Basic example:

Set NewPixelTypes = Nothing

Delphi example:

ImageLayout := UnAssigned;

PowerBuilder example:

DESTROY NewPixelTypes

6.5. How To Negotiate the Acquisition Frame Layout

You may use the following TWControl methods to negotiate the acquisition frame layout:

· To get the current and the available dimensional units of measurement (ICAP_UNITS) use GetAvailableIUnits. Use GetCurrentIUnits or GetDefaultIUnits to get only the current or the default value. Use SetIUnits to change the current unit.

· To get the current image layout frame use GetImageLayout. If successful this method will return a TWImageLayout object containing the acquisition frame coordinates, in current units.

· To get the fixed page sizes the Data Source supports use GetAvailableISupportedSizes. Use SetISupportedSizes to set the acquisition frame to a supported page size.

· To set/change the current acquisition layout use SetImageLayout (ResetImageLayout will revert the current layout to the Source’s default – to get this default do GetDefaultImageLayout) and pass the new layout as a TWImageLayout object. Like for TWContainer when setting a capability, you may use either a TWImageLayout object returned by a previous GetImageLayout or create a new TWImageLayout object.

· The current acquisition frame may also be changed by using SetIFrames and a TWFrame object as parameter (or a collection of TWFrame objects, as a TWContainer) - if the Data Source supports setting the related capability (ICAP_FRAMES).

· To change the orientation or rotate the image to transfer use SetIOrientation or SetIRotation (do not forget to check first if IC_ORIENTATION or IC_ROTATION capabilities are supported and get the supported values with GetAvailableIOrientation or GetAvailableIRotation).

6.5.1.1. Visual Basic example

This example will:

1. Set the current unit to inches.

2. Get the current image layout

3. Modify the received TWImageLayout object and pass it back to the Data Source

4. Reset the image layout

5. Create e new TWImageLayout object and set it to the Data Source

On Error GoTo errImageLayout

TWControl.SetIUnits UN_INCHES

Dim layout As TWImageLayout

Set layout = TWControl.GetImageLayout

layout.FrameRight = (layout.FrameRight - layout.FrameLeft) / 2

layout.FrameBottom = (layout.FrameBottom - layout.FrameTop) / 2

layout.FrameLeft = 0

layout.FrameTop = 0

TWControl.SetImageLayout layout

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Set layout = Nothing

TWControl.ResetImageLayout

Dim newLayout As New TWImageLayout

newLayout.FrameLeft = 0

newLayout.FrameRight = 5

newLayout.FrameTop = 0

newLayout.FrameBottom = 5

TWControl.SetImageLayout newLayout

Set newLayout = Nothing

Exit Sub

errImageLayout:

Exit Sub

6.5.1.2. Delphi 4 example

The example will show how to set an US-Letter scan page size (8.5 x 11 inches):

1. Set ICAP_UNITS to TWUN_INCHES.

2. Check if ICAP_SUPPORTEDSIZES and TWSS_USLETTER are supported.

3. If the Data Source supports ICAP_SUPPORTEDSIZES and TWSS_USLETTER set ICAP_SUPPORTEDSIZES to TWSS_USLETTER and terminate.

4. Otherwise try to set the TW_IMAGELAYOUT frame data (0, 0, 8.5, 11 inches).

SourceSupportsInches := True;

try

TWControl.SetIUnits(UN_INCHES);

except

SourceSupportsInches := False;

end;

if SourceSupportsInches then

begin

SourceSupportsUSLetter := False;

NeedToSetUSLetter := True;

try

SupportedSizesCon :=

TWControl.GetAvailableISupportedSizes(SupportedSizesCon);

for i := 1 to SupportedSizesCon.Count do

begin

x := SupportedSizesCon.Item[i].Value;

if SupportedSizesCon.Item[i].Value = SS_USLETTER then

begin

SourceSupportsUSLetter := True;

if i = SupportedSizesCon.CurrentIndex then

begin

NeedToSetUSLetter := False;

end;

break;

end;

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SupportedSizesCon := UnAssigned;

if SourceSupportsUSLetter = True and NeedToSetUSLetter = True then

begin

TWControl.SetISupportedSizes(SS_USLETTER);

SourceSupportsUSLetter := True;

End;

except

SourceSupportsUSLetter := False;

end;

end; //if SourceSupportsInches

if SourceSupportsInches and False = SourceSupportsUSLetter then

begin

// Try setting the image layout:

try

ImageLayout := CoTWImageLayout.Create;

ImageLayout.FrameLeft := 0;

ImageLayout.FrameTop := 0;

ImageLayout.FrameRight := 8.5;

ImageLayout.FrameBottom := 11;

TWControl.SetImageLayout(ImageLayout);

SourceSupportsUSLetter := True;

except

SourceSupportsUSLetter := False;

end;

ImageLayout := UnAssigned;

end;

6.5.1.3. PowerBuilder example

OLEObject ImageLayout

integer result = 0

this.object.SetIcapUnits(0) /*TWUN_INCHES*/

ImageLayout = CREATE OLEObject

if not IsNull(ImageLayout) then

result = ImageLayout.ConnectToNewObject("ObjTWAIN.TWImageLayout")

if 0 > result or IsNull(result) then

/* insert error handling code here */

else

ImageLayout.FrameLeft = 0

ImageLayout.FrameTop = 0

ImageLayout.FrameRight = 8.5

ImageLayout.FrameBottom = 11

This.object.SetImageLayout(ImageLayout)

end if

DESTROY ImageLayout

end if

6.7. How To Handle Transferred Image Data and Other Transfer Events

The ObjectTWAIN™ ActiveX Library notifies an application when an image transfer (or just an image buffer for Memory Mode) is received and when a special transfer condition occurs (e.g. all the images were transferred or a transfer error occurred) using TWControl ActiveX events.

The following table enumerates the events an ObjectTWAIN™ application may expect from a TWControl object:

Event / Meaning

Description / Action to do

When to expect

DoProcessNativeData

IMAGE DATA RECEIVED

The application receives a transferred image as a handle to a DIB in memory.

TO DO: save the DIB.

After starting the transfer sequence in Native mode (NativeMemoryAsFile is False)

DoProcessMemoryData

IMAGE DATA RECEIVED

The application receives a raw buffer containing a strip or tile memory buffer of the image.

TO DO: save the buffer; if this is the last buffer finish to assemble one image.

After starting the transfer sequence in Memory mode (NativeMemoryAsFile is False)

DoProcessFileData

IMAGE DATA RECEIVED

The application receives the file format and the file name where a transferred image was just saved.

TO DO: set the TransferFile property for the next transfer or copy the file to other location.

After starting the transfer sequence in File mode.

DoProcessNativeAsFileData

IMAGE DATA RECEIVED

The application receives the file format and the file name where a transferred image was just saved.

TO DO: set the TransferFile property for the next transfer or copy the file to other location.

After starting the transfer sequence in Native to File mode (NativeMemoryAsFile is True).

DoProcessMemoryAsFileData

IMAGE DATA RECEIVED

The application receives the file format and the file name where a transferred image was just saved.

TO DO: set the TransferFile property for the next transfer or copy the file to other location.

After starting the transfer sequence in Memory to File mode (NativeMemoryAsFile is True).

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OnFeederLoaded

FEEDER LOADED

The application is notified that the user put paper in the device’s Document Feeder.

TO DO: the application may now activate and start the image acquisition.

When a session is opened and AutoCheckFeeder is True.

OnBeginTransfers

TRANSFER(S) READY

The application is notified that the transfers are ready to begin (the Source sent the Transfer Ready signal).

After starting the transfer sequence (of any type). This event shall come only once per acquisition sequence.

OnEndTransfers

NO MORE TRANSFERS

The application is notified that all available images were transferred and the Data Source does not have more pending transfers.

TO DO: close the session.

After starting the transfer sequence (of any type). This event may come only once per acquisition sequence.

OnCancelTransfer

TRANSFER CANCELED

The application is notified that either the Source or the user canceled a transfer and the acquisition sequence.

TO DO: stop the acquisition.

After starting the transfer sequence (of any type). This event or OnEndTransfers may signal that the acquisition is finished.

OnTransferError

TRANSFER ERROR

The application is notified that a transfer error occurred (the application may receive the error code and a error text description.

TO DO: optionally inform the user about the problem and stop the acquisition.

After starting the transfer sequence (of any type).

OnPreTransfer

PRE-TRANSFER

The application is notified that a transfer is about to begin. The TWAIN session is still in state 6.

TO DO: get information about the image to be transferred.

After starting the transfer sequence (of any type). This event shall come once per image transfer in the acquisition sequence.

OnPostTransfer

POST-TRANSFER

The application is notified that a transfer completed. The TWAIN session is in state 6 or 5 (if there are no more transfers pending).

TO DO: -

After starting the transfer sequence (of any type). This event shall come once per image transfer in the acquisition sequence (excepting a canceled or failed transfer).

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OnDeviceEvent

DEVICE EVENT

The application is notified that the device triggered an event.

TO DO: read the event information and act accordingly.

After opening a session and (through SetDeviceEvents). This event may come before or after starting the acquisition.

OnUserCloseSourceUI

USER CLOSES SOURCE UI

The application is notified that the user requested to close the Data Source UI. The event parameter indicates if the user closes the DS UI in ‘OK’ or ‘Cancel’ mode.

TO DO: stop the acquisition.

After starting the transfer sequence (of any type) with the option to display the Data Source User Interface.

Note: Please see next three sections for explanations about getting image information, getting extended image information and how to scan using the device’s Document Feeder.

6.9. How To Get Extended Image Information

To get extended image information (such as barcode information) follow the next steps:

Step 1: Check if the Data Source supports this kind of extended information by calling GetIExtendedImageInfo and other capability methods (e.g. GetIBarCodeDetectionEnabled if the extended information to get is related to barcodes).

Visual Basic example (from GenProd sample, TWControl_DoProcessMemoryAsFileData):

bBarCodeDetectionEnabled = False

iMaxBarCodeSearch = 0

bBarCodeDetectionEnabled = TWControl.GetIBarCodeDetectionEnabled

AppendLog "GetIBarCodeDetectionEnabled ok"

If bBarCodeDetectionEnabled Then

iMaxBarCodeSearch = TWControl.GetCurrentIBarCodeMaxSearchPriorities

AppendLog "GetCurrentIBarCodeMaxSearchPriorities ok"

If iMaxBarCodeSearch <= 0 Then

bBarCodeDetectionEnabled = False

End If

If False = bBarCodeDetectionEnabled Then

AppendLog "Barcode detection disabled"

Exit Sub

End If

If False = TWControl.GetIExtImageInfo Then

AppendLog "GetIExtImageInfo ok, returned False"

AppendLog "No GetExtImageInfo will be requested"

Exit Sub

Else

AppendLog "GetIcapExtImageInfo ok"

End If

Step 2: Construct a TWContainer object to contain the array of extended image information objects to ask the Data Source to return data into. Initialize the TWContainer object as an array specifying the desired number of extended infos as the number of array items.

Visual Basic example (from GenProd sample, TWControl_DoProcessMemoryAsFileData):

If iMaxBarCodeSearch > 6 Then

iMaxBarCodeSearch = 6

End If

' BARCODETEXT & BARCODETYPE for each barcode, & 1 BARCODECOUNT:

iInfos = ((iMaxBarCodeSearch * 2) + 1)

Set ExtImageInfo = New TWContainer

ExtImageInfo.InitArray iInfos

Step 3: Construct the extended information objects as TWInfo objects. Initialize for each TWInfo object the InfoID property. Add the TWInfo objects to the TWContainer array.

Visual Basic example (from GenProd sample, TWControl_DoProcessMemoryAsFileData):

For i = 1 To iInfos

Set Info(i) = New TWInfo

Info(1).InfoID = EI_BARCODECOUNT

For i = 2 To iInfos

Info(i).InfoID = EI_BARCODETYPE

i = i + 1

Info(i).InfoID = EI_BARCODETEXT

For i = 1 To iInfos

ExtImageInfo.Add Info(i)

Step 4: Call the TWControl GetExtImageInfo method. If successful, the TWInfo objects in the TWContainer array shall contain the extended image information returned by the Data Source.

Visual Basic example (from GenProd sample, TWControl_DoProcessMemoryAsFileData):

TWControl.GetExtImageInfo ExtImageInfo

AppendLog "GetExtImageInfo ok"

If ExtImageInfo.Count > 0 Then

For Each Temp In ExtImageInfo

If Temp.InfoID = EI_BARCODECOUNT Then

For Each InfoItem In Temp

AppendLog "BarCodeCount: " & CStr(InfoItem)

End If

If Temp.InfoID = EI_BARCODETYPE Then

For Each InfoItem In Temp

AppendLog "BarCodeType: " & DecodeBarcode(Int(InfoItem))

End If

If Temp.InfoID = EI_BARCODETEXT Then

For Each InfoItem In Temp

AppendLog "BarCodeText: " & CStr(InfoItem)

End If

Next 'For Each Info In ExtImageInfo

End If

Step 5: After finishing with the array of TWInfo objects, destroy them and free the allocated memory.

Visual Basic example (from GenProd sample, TWControl_DoProcessMemoryAsFileData):

For i = 1 To iInfos

Set Info(i) = Nothing

Set ExtImageInfo = Nothing

Note: For the above sequence of code (from the GenProd sample) the local variable definitions and the error handling mechanism are listed next:

Dim bBarCodeDetectionEnabled As Boolean

Dim iMaxBarCodeSearch As Integer

Dim iInfos As Integer

Dim ExtImageInfo As TWContainer

Dim Info(1 To 14) As TWInfo

Dim Temp As TWInfo

Dim InfoItem As Variant

Dim i As Integer

On Error GoTo errGetExtImageInfo

‘ follows the code sequence to get extended image information

Exit Sub

errGetExtImageInfo:

AppendLog "Get extended image info failed:"

AppendLog Err.Description

7. Library Reference

R.1. ObjectTWAIN™ ActiveX/COM Controls

Control name	Interfaces	Description
TWControl	ITWControl Idispatch	TWControl is the main ActiveX control, insertable and invisible at run-time, exported by the ObjectTWAIN™ ActiveX Library. By using this control an application can select a TWAIN Data Source, open and control programatically a complete TWAIN image acquisition session.
TWContainer	ITWContainer Idispatch	Implements an array or enumeration of values or COM objects or a range of values as a COM Collection. Wrapper for TWAIN capability containers and for the array of extended image attributes.
TWSourceList	ITWSourceList Idispatch	Implements as a COM Collection a list of TWSourceInfo objects to hold information about the TWAIN Data Sources installed on system (get with GetInstalledSources).
TWSourceInfo	ITWSourceInfo Idispatch	Wrapper COM object for TWAIN Data Source identity data structure. Describes the atributes of a Data Source.
TWImageLayout	ITWImageLayout Idispatch	Wrapper COM object for TWAIN image layout data structure. Used to negotiate the acquisition frame layout.
TWImageInfo	ITWImageInfo Idispatch	Wrapper COM object for the TWAIN image info data structure. Describes the attributes of the next image to transfer or the last transferred image.
TWInfo	ITWInfo Idispatch	Wrapper COM object for the TWAIN extended information/attribute data structure. May be stored to TWContainer to create an array of infos to request extended image information from the Data Source.
TWFrame	ITWFrame Idispatch	Wrapper COM object for the TWAIN frame data structure. May be stored to TWContainer to create an enumeration or array of frames.
TWCapQuery	ITWCapQuery Idispatch	Wrapper COM object for the TWAIN query capability support data structure. Used with QueryCapability.

R.2. Other ObjectTWAIN™ COM Controls

The ObjectTWAIN™ ActiveX Library exports wrapper COM objects for all enumerated capability values defined by TWAIN Release v1.8. Each of these objects has as a single default property (named Value), of a type of the related ObjectTWAIN™ COM enumeration which defines the related capability values (e.g. there is a TWPixelTypeValue wrapper COM object for the defined ICAP_PIXELTYPE capability values, TWPixelTypeValue.Value is of type PixelType, PixelType is defined as a COM Enumeration containing aliases for the TWPT_x values defined by TWAIN).

These objects can be very useful in Visual Basic and other development environments which may be able to display in the editor a selection with the available TWAIN defined values when typing a TWControl capability method.

IMPORTANT: These objects may be replaced in almost all cases by simple numerical values (as defined by TWAIN) when calling a TWControl method to execute a capability operation. TWControl is able to handle an enumerated capability value passed as a parameter to a capability method as either a wrapper COM object or simple numerical value. If the development environment suports this, an enumerated capability value returned by ObjectTWAIN™ as a COM object will be converted automatically by the development environment to a simple value.

In Visual Basic, to request set the current value of ICAP_PIXELTYPE to TWPT_BW, you may write:

TWControl.SetIPixelType PT_BW

‘ or:

TWControl.SetIPixelType 0

‘or:

Dim BW as new TWPixelTypeValue

‘ Here VB may be able to display automatically while typing

‘ a selection box with the available PT values so you will

‘ not have to look in documentation for the PT_BW value:

BW = PT_BW

TWControl.SetIPixelType BW

Set BW = nothing

When typing code in Visual Basic to compare a received ICAP_PIXELTYPE value with a constant value, Visual Basic may display a selection list with the available values to select from and will let you select a value or type your own:

Dim PixelTypes As TWContainer

Dim pt As TWPixelTypeValue

Set PixelTypes = TWControl.GetIAvailablePixelType

For Each pt In PixelTypes

‘ Here VB may be able to display automatically while typing

‘ a selection box with the available PT values so you will

‘ not have to look in documentation to find the PT_BW value:

If pt = PW_BW Then

‘…

End If

In the following table are listed all the ObjectTWAIN™ COM wrapper objects for enumerated-type TWAIN capability values. The third column displays the ObjectTWAIN™ prefix (e.g. PT for PT_BW) and the TWAIN prefix (e.g. TWPT for TWPT_BW; PT_BW is an alias for TWPT_BW, their values are identical, 0). The values related to a single capability all have the same prefix.

COM Object Name	TWAIN Capability	Value Prefix
TWCompressionValue	ICAP_COMPRESSION	CMP/TWCP
TWPixelTypeValue	ICAP_PIXELTYPE	PT/TWPT
TWUnitsValue	ICAP_UNITS	UN/TWUN
TWXferMechValue	ICAP_XFERMECH ACAP_XFERMECH	SX/TWSX
TWCapabilityName	CAP_SUPPORTEDCAPS CAP_EXTENDEDCAPS	C/CAP IC/ICAP AC/ACAP
TWDuplexValue	CAP_DUPLEX	DX/TWDX
TWJobControlValue	CAP_JOBCONTROL	JC/TWJC
TWFilterValue	ICAP_FILTER	FT/TWFT
TWImageFileFormatValue	ICAP_IMAGEFILTER	IF/TWIF
TWLightSourceValue	ICAP_LIGHTSOURCE	LS/TWLS
TWOrientationValue	ICAP_ORIENTATION	OR/TWOR
TWBitOrderValue	ICAP_BITORDER	BO/TWBO
TWLightPathValue	ICAP_LIGHTPATH	LP/TWLP
TWPixelFlavorValue	ICAP_PIXELFLAVOR ICAP_PIXELFLAVORCODES	PF/TWPF
TWPlanarChunkyValue	ICAP_PLANARCHUNKY	PC/TWPC
TWSupportedSizesValue	ICAP_SUPPORTEDSIZES	SS/TWSS
TWBitDepthReductionValue	ICAP_BITDEPTHREDUCTION	BR/TWBR
TWAlarmsValue	CAP_ALARMS	AL/TWAL
TWDeviceEventsValue	CAP_DEVICEEVENT	DE/TWDE
TWClearBuffersValue	CAP_CLEARBUFERS	CB/TWCB
TWAudioFileFormatValue	ACAP_AUDIOFILEFORMAT	AF/TWAF
TWFeederAlignmentValue	CAP_FEEDERALIGNMENT	FA/TWFA
TWFeederOrderValue	CAP_FEEDERORDER	FO/TWFO
TWLanguageValue	CAP_LANGUAGE	LG/TWLG
TWPowerSupplyValue	CAP_POWERSUPPLY	PS/TWPS
TWPrinterValue	CAP_PRINTER	PR/TWPR
TWPrinterModeValue	CAP_PRINTERMODE	PM/TWPM
TWBarCodeSearchModeValue	ICAP_BARCODESEARCHMODE	BC/TWBD
TWPatchCodeSearchModeValue	ICAP_PATCHCODESEARCHMODE	PC/TWBD
TWFlashUsed2Value	ICAP_FLASHUSED2	FL/TWFL
TWFlipRotationValue	ICAP_FLIPROTATION	FR/TWFR
TWImageFilterValue	ICAP_IMAGEFILTER	IF/TWIF
TWNoiseFilterValue	ICAP_NOISEFILTER	NF/TWNF
TWOverScanValue	ICAP_OVERSCAN	OV/TWOV
TWBarCodeTypeValue	ICAP_SUPPORTEDBARCODETYPES ICAP_BARCODESEARCHPRIORITIES	BT/TWBT
TWDeskewStatusValue