{WebTwainObject} Scan

The properties and methods on this page live in the namespace {WebTwainObject}. {WebTwainObject} denotes the WebTwain instance. Learn about how to create a web twain object.

• Desktop Service
• Android Service

1. The following APIs are compatible with TWAIN, ICA, SANE (Windows, macOS and Linux)

Methods

Properties

Events

2. The following APIs are compatible with TWAIN and ICA

Methods

3. The following APIs are compatible with TWAIN (mostly Windows, but could also be macOS)

Methods

Properties

Events

The Android Service Edition only supports a subset of the APIs available in the Desktop Service Edition. For the APIs that are compatible with both editions, the usage remains the same. To learn how to use the APIs, please refer to the documentation for the Desktop Service Edition.

Methods

Events

AcquireImage

Start image acquisition.

Syntax

AcquireImage(
    deviceConfiguration?: DeviceConfiguration,
    successCallBack?: () => void,
    failureCallBack?: (deviceConfiguration?: DeviceConfiguration, errorCode: number, errorString: string) => void
): void;

Parameters

deviceConfiguration: Configuration for the acquisition. Please refer to DeviceConfiguration.

successCallback: A callback function that is executed if the request succeeds.

failureCallback: A callback function that is executed if the request fails.

• errorCode: The error code.
• errorString: The error string.

Availability

Usage notes

extendedImageInfoQueryLevel is 0 by default which means the following information will be retrieved (if available):

If it’s set to 1, the following will also be retrieved (if available):

If it’s set to 2, then besides what’s mentioned in the two tables above, the Dynamic Web TWAIN library will also try to query the scanner for its own custom extended image info.

Example

The example code shows 4 ways to use the API AcquireImage()

var deviceConfiguration = {
  IfShowUI: false,
  PixelType: Dynamsoft.DWT.EnumDWT_PixelType.TWPT_RGB,
  Resolution: 300,
  IfFeederEnabled: true,
  IfDuplexEnabled: false,
  IfDisableSourceAfterAcquire: true,
  IfGetImageInfo: true,
  IfGetExtImageInfo: true,
  extendedImageInfoQueryLevel: 0,
};

function successCallback() {
  console.log("successful");
}

function failureCallback(errorCode, errorString) {
  alert(errorString);
}

function AcquireImage1() {
  DWObject.SelectSource(function () {
    DWObject.OpenSource();
    DWObject.IfShowUI = false;
    DWObject.PixelType = Dynamsoft.DWT.EnumDWT_PixelType.TWPT_RGB;
    DWObject.Resolution = 300;
    DWObject.IfFeederEnabled = true;
    DWObject.IfDuplexEnabled = false;
    DWObject.IfDisableSourceAfterAcquire = true;
    DWObject.AcquireImage();
  }, failureCallback);
}

function AcquireImage2() {
  DWObject.SelectSource(function () {
    DWObject.OpenSource();
    DWObject.AcquireImage(deviceConfiguration);
  }, failureCallback);
}

function AcquireImage3() {
  DWObject.SelectSource(function () {
    DWObject.OpenSource();
    DWObject.IfShowUI = false;
    DWObject.PixelType = Dynamsoft.DWT.EnumDWT_PixelType.TWPT_RGB;
    DWObject.Resolution = 300;
    DWObject.IfFeederEnabled = true;
    DWObject.IfDuplexEnabled = false;
    DWObject.IfDisableSourceAfterAcquire = true;
    DWObject.AcquireImage(successCallback, failureCallback);
  }, failureCallback);
}

function AcquireImage4() {
  DWObject.SelectSource(function () {
    DWObject.OpenSource();
    DWObject.AcquireImage(
      deviceConfiguration,
      successCallback,
      failureCallback
    );
  }, failureCallback);
}

CloseSource

Close the data source (a TWAIN/ICA/SANE device which in most cases is a scanner) to free it to be used by other applications.

Syntax

CloseSource(): boolean;

Availability

Example

// Close the scanner source in the success/failure callback after all images are acquired. In this case, the source can be freed and used by others.
DWObject.OpenSource();
DWObject.AcquireImage(successCallback,failureCallback);

function successCallback() {
  console.log("successful");
  DWObject.CloseSource();
}

function failureCallback(errorCode, errorString) {
  alert(errorString);
  DWObject.CloseSource();
}

CloseSourceAsync

Close the data source (a TWAIN/ICA/SANE device which in most cases is a scanner) to free it to be used by other applications.

Syntax

CloseSourceAsync(): Promise<boolean>;

Availability

DisableSource

Disable the data source (a TWAIN/ICA/SANE device which in most cases is a scanner) to stop the acquiring process. If the data source’s user interface is displayed, it will be closed.

Syntax

DisableSource(): boolean;

Availability

Usage notes

After DisableSource() is called, the Source is still open and you can continue to acquire images by calling AcquireImage() or EnableSource() .

EnableSource

Enable the data source to start the acquiring process.

Syntax

EnableSource(): boolean;

Availability

Usage notes

The method is equivalent to AcquireImage() without parameters.

EnableSourceUI

Display the TWAIN source’s built-in user interface.

Syntax

EnableSourceUI(
    successCallBack: () => void,
    failureCallBack: (errorCode: number, errorString: string) => void
): void;

Parameters

successCallback: A callback function that is executed if the request succeeds.

failureCallback: A callback function that is executed if the request fails.

• errorCode: The error code.
• errorString: The error string.

Availability

Usage notes

This method enables the user to manipulate the settings for scanning but not start an actual scan. It only works if the source supports the capability CAP_ENABLEDSUIONLY . User can call GetCustomDSDataEx() to save the settings in the callback successCallBack and later call SetCustomDSDataEx() to apply the settings before starting a scan.

OpenSource

Load a data source to get it ready to acquire images.

Syntax

OpenSource(): boolean;

Availability

Example

DWObject.GetSourceNames(); // for example ['PaperStream IP fi-7300NX Net', 'TWAIN2 FreeImage Software Scanner']
DWObject.SelectSourceByIndex(0); // choose scanner with the name "PaperStream IP fi-7300NX Net"
DWObject.OpenSource();
DWObject.AcquireImage();

OpenSourceAsync

Load a data source to get it ready to acquire images.

Syntax

OpenSourceAsync(): Promise<boolean>;

Availability

GetSourceNames

Return all available data sources (scanners, etc.) and optionally all detailed information about them.

Syntax

GetSourceNames(bIncludeDetails?: boolean): string[] | SourceDetails[];

Parameters

bIncludeDetails: Whether to return more details about the data sources or just their names.

Arguments

SourceDetails: Please refer to SourceDetails.

Availability

Example

DWObject.GetSourceNames(); // return a list of scanner sources such as ['PaperStream IP fi-7300NX Net', 'TWAIN2 FreeImage Software Scanner']

GetSourceNamesAsync

Return all available data sources (scanners, etc.) and optionally all detailed information about them.

Syntax

GetSourceNamesAsync(bIncludeDetails: boolean): Promise<string[] | ISourceDetails[]>;

Parameters

bIncludeDetails: Whether to return more details about the data sources or just their names.

Availability

SelectSource

Bring up the Source Selection User Interface (UI) for the user to choose a data source.

Syntax

SelectSource(
    successCallBack?: () => void,
    failureCallBack?: (errorCode: number, errorString: string) => void
): boolean | string;

Parameters

successCallback: A callback function that is executed if the request succeeds.

failureCallback: A callback function that is executed if the request fails.

• errorCode: The error code.
• errorString: The error string.

Availability

Usage notes

• It’s recommended to use this API asynchronously by pass arguments to the parameters successCallback and failureCallback.
• On Windows and Windows only, you can call this method with no arguments so that it runs synchronously and return a boolean value.

Example

DWObject.SelectSource(
  function () {
    DWObject.OpenSource();
    DWObject.AcquireImage();
  },
  function (errorCode, errorString) {
    console.log(errorString);
  }
);

SelectSourceAsync

Bring up the Source Selection User Interface (UI) for the user to choose a data source.

Syntax

SelectSourceAsync(deviceType?: Dynamsoft.DWT.EnumDWT_DeviceType | number): Promise<number>;

Parameters

deviceType: Specify the device type of scanners. Please refer to EnumDWT_DeviceType.

Availability

Example

DWObject.SelectSourceAsync()
  .then(function (sourceIndex) {
    console.log(sourceIndex);
    return DWObject.AcquireImageAsync();
  })
  .catch(function (e) {
    console.log(e);
  });

SelectSourceByIndex

Select a data source by its index.

Syntax

SelectSourceByIndex(index: number): boolean;

Parameters

index: The index of the data source.

Availability

Example

DWObject.GetSourceNames(); // for example ['PaperStream IP fi-7300NX Net', 'TWAIN2 FreeImage Software Scanner']
DWObject.SelectSourceByIndex(0); // choose scanner with the name "PaperStream IP fi-7300NX Net"
DWObject.OpenSource();
DWObject.AcquireImage();

SelectSourceByIndexAsync

Select a data source by its index.

Syntax

SelectSourceByIndexAsync(index: number): Promise<boolean>;

Parameters

index: The index of the data source.

Availability

Example

DWObject.SelectSourceByIndexAsync(0)
  .then(() => {
    return DWObject.OpenSourceAsync();
  })
  .then(() => {
    return DWObject.AcquireImageAsync();
  });

SetOpenSourceTimeout

Sets a timer which stops the data source opening process once it expires.

Syntax

SetOpenSourceTimeout(duration: number): boolean;

Parameters

duration: Define the duration of the timer (in milliseconds).

Availability

Example

DWObject.SelectSource(function () {
  DWObject.SetOpenSourceTimeout(3000); // stop the opening process if the source cannot be opened within 3000 ms.
  DWObject.OpenSource();
  DWObject.AcquireImage();
});

startScan

Start the acquisition by passing all settings at once.

Syntax

startScan(scanSetup: ScanSetup): Promise<IScanSetup>;

Parameters

scanSetup: Configuration for the acquisition. Please refer to ScanSetup.

Availability

Sample

Make use of the API startScan

CancelAllPendingTransfers

Cancels all pending transfers.

Syntax

CancelAllPendingTransfers(): boolean;

Availability

Usage notes

This method is only valid in the events OnPreAllTransfers, OnPreTransfer and OnPostTransfer.

CloseSourceManager

Closes and unloads Data Source Manager.

Syntax

CloseSourceManager(): boolean;

Availability

Example

DWObject.CloseSourceManager();

CloseSourceManagerAsync

Closes and unloads Data Source Manager.

Syntax

CloseSourceManagerAsync(): Promise<boolean>;

Availability

CloseWorkingProcess

Closes the scanning process to release resources on the machine.

Syntax

CloseWorkingProcess(): boolean;

Availability

Usage notes

In the HTML5 edition, Dynamic Web TWAIN uses a separate process to communicate with the scanners. When it’s not scanning, you can choose to close this process to release the resources (CPU, memory, etc.) used on the machine.

FeedPage

Ejects the current page and begins scanning the next page in the document feeder.

Syntax

FeedPage(): boolean;

Availability

Usage notes

Use this method after OpenSource() is called and make sure IfFeederEnabled is true .

GetCustomDSData

Get the custom data source data and saves the data in a specified file.

Syntax

GetCustomDSData(fileName: string): boolean;

Parameters

fileName: The path of the file to save the data source data to.

Availability

Usage notes

Typically, the data source data file is set by the method SetCustomDSData().

Example

// Please note, the API only works for TWAIN driver.
DWObject.GetCustomDSData("C:\\Users\\UserName\\Desktop\\ProfileName");

GetCustomDSDataEx

Gets custom DS data and returns it in a base64 string.

Syntax

GetCustomDSDataEx(): string;

Availability

Usage notes

Typically, the data source data file is set by the method SetCustomDSDataEx().

Example

// Please note, the API only works for TWAIN driver.
DWObject.GetCustomDSDataEx(); // Return a base64 string

GetSourceNameItems

Get the name of a data source by its index in data source manager source list.

Syntax

GetSourceNameItems(index: number): string;

Parameters

index: The index of the data source.

Availability

Example

DWObject.GetSourceNames(); // [scanner 1, scanner 2, scanner 3...]
DWObject.GetSourceNameItems(0); // return the name of scanner 1

OpenSourceManager

Load and open data source manager.

Syntax

OpenSourceManager(): boolean;

Availability

Usage notes

If application identification needs to be set, it should be set before this API.

Example

DWObject.OpenSourceManager(); 

OpenSourceManagerAsync

Load and open data source manager.

Syntax

OpenSourceManagerAsync(): Promise<boolean>;

Availability

Usage notes

If application identification needs to be set, it should be set before this API.

ResetImageLayout

Reset the image layout in the data source.

Syntax

ResetImageLayout(): boolean;

Availability

Usage notes

To set the image layout manually, you can use SetImageLayout()

RewindPage

If called while {IfFeederEnabled} property is true, the data source will return the current page to the input area and return the last page from the output area into the acquisition area.

Syntax

RewindPage(): boolean;

Availability

Usage notes

Use this method after OpenSource() method and make sure IfFeederEnabled is true .

SetCustomDSData

Sets custom data source data to be used for scanning, the data is stored in a file which can be regarded as a scanning profile.

Syntax

SetCustomDSData(fileName: string): boolean;

Parameters

fileName: The path of the file.

Availability

Usage notes

Typically, the data source data file is created by the method GetCustomDSData().

Example

// Please note, the API only works for TWAIN driver.
DWObject.SetCustomDSData("C:\\Users\\UserName\\Desktop\\ProfileName");

SetCustomDSDataEx

Set custom data source data to be used for scanning, the input is a base64 string.

Syntax

SetCustomDSDataEx(dsDataString: string): boolean;

Parameters

dsDataString: The string that contains custom data source data.

Availability

Usage notes

Typically the data source data string is created by the method GetCustomDSDataEx()

// Please note, the API only works for TWAIN driver.
DWObject.SetCustomDSData("the base64 string of your profile");

SetFileXferInfo

Set the file transfer information to be used in File Transfer mode.

Syntax

SetFileXferInfo(
    fileName: string,
    fileFormat: Dynamsoft.DWT.EnumDWT_FileFormat | number
): boolean;

Parameters

fileName: The path to transfer the file to.

fileFormat: The format of the file.

Availability

Usage notes

Make sure the format you set is supported by the data source.

Example argument for the parameter fileName

• “C:\webtwain.jpg”: The next scanned image will be compressed as a JPEG file named webtwain and transferred to “C:\”.
• “C:\webtwain” + <> + “.jpg”: The scanned images will result in “C:\webtwain1.jpg”, “C:\webtwain2.jpg”, “C:\webtwain3.jpg”, etc.
• “C:\webtwain” + <%06d> + “.jpg”: The scanned images will result in “C:\webtwain000001.jpg”, “C:\webtwain000002.jpg”, “C:\webtwain000003.jpg”, etc.

Check out the available formats Dynamsoft.DWT.EnumDWT_FileFormat.

Example

DWObject.OpenSource();
DWObject.TransferMode = Dynamsoft.DWT.EnumDWT_TransferMode.TWSX_FILE;
if (DWObject.TransferMode === Dynamsoft.DWT.EnumDWT_TransferMode.TWSX_FILE) {
    if (
        DWObject.SetFileXferInfo(
            "C:\\Temp\\WebTWAIN<%06d>.bmp",
            Dynamsoft.DWT.EnumDWT_FileFormat.TWFF_BMP
        )
    ) {
          DWObject.IfShowUI = true;
          DWObject.AcquireImage();
    }
}

SetImageLayout

Set the left, top, right, and bottom sides of the image layout rectangle for the current data source. The image layout rectangle defines a frame of the data source’s scanning area to be acquired.

Syntax

SetImageLayout(
    left: number,
    top: number,
    right: number,
    bottom: number
): boolean;

Parameters

left: Specify the rectangle (leftmost coordinate).

top: Specify the rectangle (topmost coordinate).

right: Specify the rectangle (rightmost coordinate).

bottom: Specify the rectangle (bottommost coordinate).

Availability

Usage notes

The arguments set to the parameters left , top , right , bottom are based on the value of the Unit property which is inches by default.

This API is device-dependent. If a data source doesn’t support the customization of the scan area, this method might not work correctly.

Since there are several ways to negotiate the scan area, it becomes confusing when deciding what should take precedence.

The TWAIN Working Group has suggested the following behavior

• If the current frame is set by SetImageLayout . The same frame shall be what you get with the APIs CapGetFrameBottom(), CapGetFrameLeft(), CapGetFrameRight(), CapGetFrameTop() and the property PageSize shall return TWSS_NONE (0).
• If the current frame is set from negotiating the capability ICAP_FRAMES with the method CapSetFrame(), the property PageSize shall return TWSS_NONE (0) and the image layout shall reflect the same frame with the properties ImageLayoutFrameBottom, ImageLayoutFrameLeft, ImageLayoutFrameRight and ImageLayoutFrameTop.
• If the current fixed frame is set by the property PageSize, the same dimensions shall be reflected in the APIs CapGetFrameBottom(), CapGetFrameLeft(), CapGetFrameRight(), CapGetFrameTop() as well as ImageLayoutFrameBottom, ImageLayoutFrameLeft, ImageLayoutFrameRight and ImageLayoutFrameTop. Note, however, the orientation (in other words, whether it’s in the portrait mole or landscape mode) also plays a role in the order of the values.

Example

DWObject.SelectSource();
DWObject.OpenSource();
DWObject.IfShowUI = false;
DWObject.Unit = Dynamsoft.DWT.EnumDWT_UnitType.TWUN_PIXELS;
DWObject.SetImageLayout(50, 50, 100, 100);
DWObject.AcquireImage();

BitDepth

Return or set the pixel bit depth for the current value of PixelType .

Syntax

BitDepth: number;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage() .

By default, the bit depth is 1 for TWPT_BW , 8 for TWPT_GRAY and 24 for TWPT_RGB .

IfAppendImage

Return or set whether newly acquired images are inserted or appended.

Syntax

IfAppendImage: boolean;

Availability

Usage notes

The value of this property defaults to true , which means that the newly acquired image will be appended to the last image in the buffer.

If it’s set to false , the images will be inserted before the current image. The important thing to note is that, by design, the current image is always the last acquired one which means that the images acquired after setting IfAppendImage to false will be displayed / retained in the reverse order.

Here is an article to demonstrate how to insert new images to a specified index.

IfDisableSourceAfterAcquire

Return or set whether to close the built-in User Interface after all images have been acquired.

Syntax

IfDisableSourceAfterAcquire: boolean;

Availability

Usage notes

This property only makes sense when IfShowUI is set to true .

Example

DWObject.OpenSource();
DWObject.IfDisableSourceAfterAcquire = true; // Close the scanner UI after images acquired.
DWObject.IfShowUI = true;
DWObject.AcquireImage(successCallback,failureCallback);

function successCallback() {
    DWObject.CloseSource();
}

function failureCallback(errorCode, errorString) {
    DWObject.CloseSource();
}

IfDuplexEnabled

Return or set whether to enable duplex scanning (in other words, whether to scan both sides of the paper).

Syntax

IfDuplexEnabled: boolean;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage() .

Not all scanners support duplex scanning. To confirm, check the user manual of the device or check the value of Duplex after OpenSource() .

Example

DWObject.OpenSource();

if (DWObject.Duplex != 0) { // Note: DWObject.Duplex doesn't support Linux.
    DWObject.IfDuplexEnabled = true;
}

DWObject.AcquireImage();

IfFeederEnabled

Return or set whether a data source’s Automatic Document Feeder (ADF) is enabled for scanning.

Syntax

IfFeederEnabled: boolean;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage() .

If the property is set to true , the data source will try acquiring images from the document feeder first. If the data source doesn’t have a document feeder, the flatbed will be used.

Example

DWObject.OpenSource();
DWObject.IfFeederEnabled = true;
DWObject.AcquireImage();

IfShowUI

Return or set whether the data source displays the user interface when scanning.

Syntax

IfShowUI: boolean;

Availability

Usage notes

If the property is set to true , the data source will display its user interface when AcquireImage() is called. Otherwise, the UI will not be displayed and the scan will start immediately.

It’s recommended to use this API after OpenSource() is called.

Example

DWObject.OpenSource();
DWObject.IfShowUI = true; // display the scanner UI before acquiring image
DWObject.AcquireImage();

ImageCaptureDriverType

Return or set the driver type which determines the type of sources to use.

Syntax

ImageCaptureDriverType: Dynamsoft.DWT.EnumDWT_Driver | number;

Availability

Usage notes

Set this property right after the SDK is initialized or after calling CloseSourceManager() and OpenSourceManager() .

The allowed values for EnumDWT_Driver are

PageSize

Return or set the page size the data source uses to acquire images.

Syntax

PageSize: Dynamsoft.DWT.EnumDWT_CapSupportedSizes | number;

Parameters

PageSize: Please refer to EnumDWT_CapSupportedSizes

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage().

PixelType

Return or set the pixel type used when acquiring images.

Syntax

PixelType: Dynamsoft.DWT.EnumDWT_PixelType | number;

Parameters

PixelType: Please refer to EnumDWT_PixelType

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage().

Resolution

Return or set the resolution used when acquiring images.

Syntax

Resolution: number;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage().

SourceCount

Returns how many data sources are available on the local system.

Syntax

readonly SourceCount: number;

Availability

BlankImageThreshold

Retrun or set the dividing line between black and white.

Syntax

BlankImageThreshold: number;

Availability

Usage notes

BlankImageThreshold ranges from 0 to 255 and is 128 by default, it’s only effective when [ PixelType ] is set to TWPT_BW . The bigger the value is, the more likely an image may be regarded as blank.

Brightness

Return or set the brightness to be used for scanning by the data source.

Syntax

Brightness: number;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage() .

Typically, the value range is -1000 ~ 1000 where -1000 indicates the darkest and 1000 the brightest.

Contrast

Return or set Contrast to be used for scanning by the data source.

Syntax

Contrast: number;

Availability

Usage notes

Set this property after OpenSource() and before AcquireImage() .

Typically, the value range is -1000 ~ 1000 where -1000 indicates the darkest and 1000 the brightest.

CurrentSourceName

Return the device name of current source.

Syntax

readonly CurrentSourceName: string;

Availability

Usage notes

If no source is currently selected, this property returns “”.

DataSourceStatus

Return a value that indicates the data source status.

Syntax

DataSourceStatus: number;

Availability

Usage notes

DefaultSourceName

Return the name of the last used source.

Syntax

DefaultSourceName: string;

Availability

Duplex

Return whether the source supports duplex. If yes, it further returns the level of duplex the data source supports.

Syntax

readonly Duplex: Dynamsoft.DWT.EnumDWT_DUPLEX | number;

Availability

Usage notes

1-pass means the paper gets scanned on both sides at the same time. 2-pass means the paper passes the light bar twice to get both sides scanned separately.

This property does not support Linux.

IfAutoBright

Return or set whether to enable the data source’s auto-brightness feature.

Syntax

IfAutoBright: boolean;

Availability

IfAutoDiscardBlankpages

Return or set whether the data source (the scanner) discards blank images during scanning automatically.

Syntax

IfAutoDiscardBlankpages: boolean;

Availability

Usage notes

The property works only if the device and its driver supports discarding blank pages. You can find whether your device supports this capbility from its user manual.

Alternatively, the Dynamic Web TWAIN library can also detect blank images after they are transferred.

IfAutoFeed

Return or set whether to enable the data source’s automatic document feeding process.

Syntax

IfAutoFeed: boolean;

Availability

Usage notes

If set to true , the data source will automatically feed the next page from the document feeder as soon as the previous page is scanned.

IfAutomaticBorderDetection

Return or set whether to enable the data source’s automatic border detection feature.

Syntax

IfAutomaticBorderDetection: boolean;

Availability

Usage notes

The property works only if the device and its driver support detecting the border automatically. You can find whether your device supports this capbility from its user manual.

Once enabled, the data source (scanner) will automatically detect the borders of the document so that no extra margins are scanned.

IfAutomaticDeskew

Return or set whether to enable the data source’s automatic skew correction feature.

Syntax

IfAutomaticDeskew: boolean;

Availability

Usage notes

The property works only if the device and its driver supports automatical deskewing. You can find whether your device supports this capbility from its user manual.

IfAutoScan

Return or set whether to enable the data source’s automatic document scanning process.

Syntax

IfAutoScan: boolean;

Availability

Usage notes

This property is only valid when IfFeederEnabled is set to true .

The fundamental assumption behind this property is that the device may be able to capture the number of images indicated by the property XferCount without waiting for the Application to request the image transfers. This is only possible if the device has internal buffers capable of caching the images it captures.

IfFeederLoaded

Return whether or not there are documents loaded in the data source’s feeder.

Syntax

readonly IfFeederLoaded: boolean;

Availability

Usage notes

This property is only valid when IfFeederEnabled and IfPaperDetectable are true .

IfPaperDetectable

Return whether the Source has a paper sensor that can detect pages on the ADF or Flatbed.

Syntax

readonly IfPaperDetectable: boolean;

Availability

Usage notes

Check this property after OpenSource() is called.

IfShowIndicator

Return or set whether the data source displays a progress indicator during acquisition and transfer.

Syntax

IfShowIndicator: boolean;

Availability

Usage notes

This property works only when IfShowUI is set to false .

The indicator will only be hidden if you set both IfShowUI and IfShowIndicator to false .

IfUIControllable

Return whether the data source supports acquisitions with the UI (User Interface) disabled.

Syntax

readonly IfUIControllable: boolean;

Availability

Usage notes

Check this property after OpenSource() is called.

IfUseTwainDSM

Return or set whether the new TWAIN DSM (data source Manager) is used for acquisitions. The new TWAIN DSM is a DLL called ‘TWAINDSM.dll’ while the default or old DSM is called ‘twain_32.dll’.

Syntax

IfUseTwainDSM: boolean;

Availability

Usage notes

This property should be set before any TWAIN related methods or properties are called or set.

ImageLayoutFrameBottom

Return the value of the bottom edge of the current image frame (in Unit).

Syntax

readonly ImageLayoutFrameBottom: number;

Availability

ImageLayoutFrameLeft

Return the value of the left edge of the current image frame (in Unit).

Syntax

readonly ImageLayoutFrameLeft: number;

Availability

ImageLayoutFrameNumber

Returns the frame number of the current image.

Syntax

readonly ImageLayoutFrameNumber: number;

Availability

Usage Notes Usually a chronological index of the acquired frames, these frames are related to one another in some way. Usually, they were acquired from the same page. The source assigns these values. Initial value is 1. Reset when a new page is acquired.

ImageLayoutFrameNumber property, along with other properties about the current image information, is valid only in the OnPreTransfer and OnPostTransfer events. The frame information here is only about the current frame. To get the information about all the frames to be transferred in an acquire session, please use capability negotiation. The capability to be negotiated is ICAP_FRAMES (4372).

ImageLayoutFrameRight

Return the value of the right edge of the current image frame (in Unit).

Syntax

readonly ImageLayoutFrameRight: number;

Availability

ImageLayoutFrameTop

Return the value of the top edge of the current image frame (in Unit).

Syntax

readonly ImageLayoutFrameTop: number;

Availability

ImageLayoutDocumentNumber

Return the document number of the current image.

Syntax

readonly ImageLayoutDocumentNumber: number;

Availability

ImageLayoutPageNumber

Return the page number of the current image.

Syntax

readonly ImageLayoutPageNumber: number;

Availability

ImageBitsPerPixel

Return the bit depth of the current image.

Syntax

readonly ImageBitsPerPixel: number;

Availability

ImageLength

Return the length of the current image.

Syntax

readonly ImageLength: number;

Availability

ImageWidth

Return the width of the current image.

Syntax

readonly ImageWidth: number;

Availability

ImageXResolution

Return the horizontal resolution of the current image.

Syntax

readonly ImageXResolution: number;

Availability

ImageYResolution

Return the vertical resolution of the current image.

Syntax

readonly ImageYResolution: number;

Availability

ImagePixelType

Return the pixel type of the current image.

Syntax

readonly ImagePixelType: Dynamsoft.DWT.EnumDWT_PixelType | number;

Availability

MagData

Return the data of the magnetic data if the data source supports magnetic data recognition.

Syntax

readonly MagData: string;

Availability

MagType

Return the type of the magnetic data if the data source supports magnetic data recognition.

Syntax

readonly MagType: Dynamsoft.DWT.EnumDWT_MagType | number;

Availability

Usage notes

The numbers returned by these APIs are based on the value of the Unit property which by default means “inches”.

These APIs are only valid in the callbacks for the events OnPreTransfer and OnPostTransfer.

MagData and MagType are device-dependent. Check the user manual of the device to see if magnetic data recognition is supported.

PendingXfers

Return the number of transfers the data source is ready to supply upon demand.

Syntax

readonly PendingXfers: number;

Availability

Usage notes

This property is only valid in the event OnPostTransfer.

The data source returns -1 if it is not sure how many transfers are pending which normally occurs when the ADF (Automatic Document Feeder) is used.

PixelFlavor

Return or set the pixel flavor to be used for acquiring images.

Syntax

PixelFlavor: number;

Availability

Usage notes

Available values:

• 0: Chocolate. Zero pixel represents darkest shade
• 1: Vanilla. Zero pixel represents lightest shade.

TransferMode

Return or set the data source’s transfer mode.

Syntax

TransferMode: Dynamsoft.DWT.EnumDWT_TransferMode | number;

Availability

Usage notes

Allowed values are

• TWSX_NATIVE

  0: The default mode. In this mode, the whole image is transfered in a single memory block.

• TWSX_FILE

  1: In this mode, the image is transfered to a specified file on the disk directly. This mode is ideal when transferring large images that might encounter memory limitations with Native mode. Check out SetFileXferInfo for more information.

• TWSX_MEMORY

  2: In this mode, the image is transferred in multiple memory blocks. It’s ideal for transferring very large images or a large number of images in a short time.

TWSX_NATIVE and TWSX_MEMORY are required by all TWAIN data sources while TWSX_FILE is not. Therefore, make sure the data source supports TWSX_FILE before you use it.

Unit

Return or set the unit of measure for all quantities. Note that this setting is only effective for TWAIN/ICA (hardware) related operations.

Syntax

Unit: Dynamsoft.DWT.EnumDWT_UnitType | number;

Availability

Usage notes

Allowed values are

XferCount

Return and set the number of images your application is willing to accept for each scan job.

Syntax

XferCount: number;

Availability

Usage notes

Allowed values are between -1 and 215 where -1 indicate multiple images.

OnPostAllTransfers

This event is triggered when all page(s) have been scanned and transferred.

Syntax

RegisterEvent("OnPostAllTransfers", function () {});

Availability

Usage notes

This event fires after all pages in the document feeder have been scanned and transferred. This is a good place to upload the images, detect barcodes, discard blank pages, etc.

Example

DWObject.RegisterEvent("OnPostAllTransfers", function () {
  console.log("All images are transferred.");
});

OnPostTransfer

This event is triggered after each page has been scanned and transferred.

Syntax

RegisterEvent("OnPostTransfer", function () {});

Availability

Example

DWObject.RegisterEvent("OnPostTransfer", function () {
  console.log("An image has been scanned");
});

OnPostTransferAsync

This event is triggered after each page has been scanned and transferred. This is the asynchronous counterpart to the synchronous event {OnPostTransfer}.

Syntax

RegisterEvent("OnPostTransferAsync", function (outputInfo: OutputInfo) {});

Parameters

outputInfo: Detailed information about the image that just got transferred. Please refer to OutputInfo.

Availability

Example

DWObject.RegisterEvent("OnPostTransferAsync", function (outputInfo) {
  console.log("The image ID is " + outputInfo.imageId);
});

OnPreAllTransfers

This event is triggered when all images are scanned and ready to be transferred.

Syntax

RegisterEvent("OnPreAllTransfers", function () {});

Availability

Usage notes

Multiple transfers may occur in two cases

• Multiple images are scanned through the ADF(Auto Document Feeder)
• Multiple frames are scanned on one single page

In such cases, the event OnPreTransfer is triggered multiple times but OnPreAllTransfers is triggerred only once.

In the callback function of this event, you can call CancelAllPendingTransfers() to cancel all the transfers.

OnPreTransfer

This event is triggered when a page has been scanned and is ready to be transferred.

Syntax

RegisterEvent('OnPreTransfer',function(){...});

Availability

Usage notes

In the callback function of this event, you can

• Check PendingXFERs for the number of pending transfers.
• Check the information about the transferred image including ImageLayoutDocumentNumber , ImageLayoutFrameLeft , ImageLayoutFrameTop , ImageLayoutFrameRight , ImageLayoutFrameBottom , ImageLayoutPageNumber , ImageLayoutFrameNumber , etc.
• Call CancelAllPendingTransfers() to cancel all the rest of the transfers.

OnSourceUIClose

This event is triggered when the user interface of the data source is closed manually by the user.

Syntax

RegisterEvent("OnSourceUIClose", function () {});

Availability

getCapabilities

Gets detailed information about all capabilities of the current data source.

Syntax

getCapabilities(
    successCallback: (capabilityDetails: CapabilityDetails[]) => void,
    failureCallback: (errorCode: number, errorString: string) => void
): void;

Parameters

successCallback: A callback function that is executed if the request succeeds.

• capabilityDetails: Detailed information about the specified capabilities. Please refer to CapabilityDetails.

failureCallback: A callback function that is executed if the request fails.

• errorCode: The error code.
• errorString: The error string.

Availability

setCapabilities

Sets up one or multiple capabilities in one call.

Syntax

setCapabilities(
    capabilities: Capabilities,
    successCallback: (capabilities: Capabilities) => void,
    failureCallback: (capabilities: Capabilities) => void
): void;

Parameters

capabilities: An object that describes how to set capabilities.

successCallback: A callback function that is executed if the request succeeds.

• capabilities: The capabilities to set.

failureCallback: A callback function that is executed if the request fails.

• capabilities: The capabilities to set.

Please refer to Capabilities.

Availability

Usage notes

To make things easier, Dynamsoft designed the API with a simplified parameter Capabilities which only requires the minimum information for setting a capability: a number to specify the capability and the value to set to it. Underneath, Dynamsoft takes care of container type setting, value type setting as well as data validation.

Pay attention to the argument you set to the overall parameter exception and the individual parameter exception for each capability. If the overall parameter is set to fail , the setting will abort as soon as an exception is raised while setting any of the capabilities. Otherwise, ignore means to carry on setting the next capability even when the previous one failed. Aside from the overall parameter, the individual exception is optional but takes precedence if set. In other words, you can set the overall exception to ignore and then set the individual one to fail for the capabilities which you think are important. This way, you get notified if these important capabilities failed to be set while other less-important ones are ignored when setting them failed.

Example

DWObject.SelectSourceByIndex(0);
DWObject.IfShowUI = false;
DWObject.OpenSource();
DWObject.setCapabilities(
  {
    exception: "ignore",
    capabilities: [
      {
        capability: Dynamsoft.DWT.EnumDWT_Cap.ICAP_CONTRAST, // your own capability
        curValue: 500, // your own curValue
      },
      {
        capability: Dynamsoft.DWT.EnumDWT_Cap.CAP_PRINTERSTRING, // your own capability
        curValue: "abc", // your own curValue
        exception: "fail",
      },
      {
        capability: Dynamsoft.DWT.EnumDWT_Cap.ICAP_PIXELTYPE, // your own capability
        curValue: 0, // your own curValue
      },
    ],
  },
  function (successData) {
    DWObject.AcquireImage(
      function () {},
      function () {
        console.log(DWObject.ErrorString);
      }
    );
  },
  function (errorData) {
    console.error(errorData);
    DWObject.AcquireImage(
      function () {},
      function () {
        console.log(DWObject.ErrorString);
      }
    );
  }
);

GetDevicesAsync

Return all available devices (scanners, eSCL scanners, etc.) for the device type (if specified)

Syntax

GetDevicesAsync(deviceType?: Dynamsoft.DWT.EnumDWT_DeviceType | number, refresh?:boolean): Promise<Device[]>;

Parameters

deviceType: The device type. Please refere to EnumDWT_DeviceType

refresh: Default value is false

Arguments

Device: Please refer to Device.

Example

DWObject.GetDevicesAsync().then((deviceList)=>{
  return DWObject.SelectDeviceAsync(deviceList[0])  //Select the first device
}).then(()=>{
    return DWObject.AcquireImageAsync({}) 
}).catch((e)=>{
    console.error(e)
})

Availability

SelectDeviceAsync

Select the device to use for scanning

Syntax

SelectDeviceAsync(device: Device): Promise< boolean>;

Example

DWObject.GetDevicesAsync().then((deviceList)=>{
  return DWObject.SelectDeviceAsync(deviceList[0])  //Select the first device
}).then(()=>{
    return DWObject.AcquireImageAsync({}) 
}).catch((e)=>{
    console.error(e)
})

Parameters

device: the device object. Please refer to Device.

Availability

AcquireImageAsync

Scan documents into another DWObject control. eSCL is not supported.

Syntax

AcquireImageAsync(deviceConfiguration?: DeviceConfiguration): Promise< boolean>;

Parameters

deviceConfiguration: The device configuration. Please refer to DeviceConfiguration.

Availability

Example

DWObject.GetDevicesAsync().then((deviceList)=>{
  return DWObject.SelectDeviceAsync(deviceList[0])  //Select the first device
}).then(()=>{
    return DWObject.AcquireImageAsync({}) 
}).catch((e)=>{
    console.error(e)
})