chrome.documentScan

Description

Use the chrome.documentScan API to discover and retrieve images from attached document scanners.

Permissions

documentScan

Availability

Chrome 44+ ChromeOS only

Document Scan API

The Document Scan API is designed to allow apps and extensions to view the content of paper documents on an attached document scanner.

Types

CancelScanResponse

Pending

Properties

  • job

    string

    Provides the same job handle that was passed to cancelScan().

  • The backend's cancel scan result. If the result is OperationResult.SUCCESS or OperationResult.CANCELLED, the scan has been cancelled and the scanner is ready to start a new scan. If the result is OperationResult.DEVICE_BUSY , the scanner is still processing the requested cancellation; the caller should wait a short time and try the request again. Other result values indicate a permanent error that should not be retried.

CloseScannerResponse

Pending

Properties

  • The result of closing the scanner. Even if this value is not SUCCESS, the handle will be invalid and should not be used for any further operations.

  • scannerHandle

    string

    The same scanner handle as was passed to closeScanner.

Configurability

Pending

How an option can be changed.

Enum

"NOT_CONFIGURABLE"
The option is read-only.

"SOFTWARE_CONFIGURABLE"
The option can be set in software.

"HARDWARE_CONFIGURABLE"
The option can be set by the user toggling or pushing a button on the scanner.

ConnectionType

Pending

Indicates how the scanner is connected to the computer.

Enum

"UNSPECIFIED"

"USB"

"NETWORK"

ConstraintType

Pending

The data type of constraint represented by an OptionConstraint.

Enum

"INT_RANGE"
The constraint on a range of OptionType.INT values. The min, max, and quant properties of OptionConstraint will be long, and its list propety will be unset.

"FIXED_RANGE"
The constraint on a range of OptionType.FIXED values. The min, max, and quant properties of OptionConstraint will be double, and its list property will be unset.

"INT_LIST"
The constraint on a specific list of OptionType.INT values. The OptionConstraint.list property will contain long values, and the other properties will be unset.

"FIXED_LIST"
The constraint on a specific list of OptionType.FIXED values. The OptionConstraint.list property will contain double values, and the other properties will be unset.

"STRING_LIST"
The constraint on a specific list of OptionType.STRING values. The OptionConstraint.list property will contain DOMString values, and the other properties will be unset.

DeviceFilter

Pending

Properties

  • local

    boolean optional

    Only return scanners that are directly attached to the computer.

  • secure

    boolean optional

    Only return scanners that use a secure transport, such as USB or TLS.

GetOptionGroupsResponse

Pending

Properties

  • groups

    OptionGroup[] optional

    If result is SUCCESS, provides a list of option groups in the order supplied by the scanner driver.

  • The result of getting the option groups. If the value of this is SUCCESS, the groups property will be populated.

  • scannerHandle

    string

    The same scanner handle as was passed to getOptionGroups.

GetScannerListResponse

Pending

Properties

  • The enumeration result. Note that partial results could be returned even if this indicates an error.

  • scanners

    ScannerInfo[]

    A possibly-empty list of scanners that match the provided DeviceFilter.

OpenScannerResponse

Pending

Properties

  • options

    object optional

    If result is SUCCESS, provides a key-value mapping where the key is a device-specific option and the value is an instance of ScannerOption.

  • The result of opening the scanner. If the value of this is SUCCESS, the scannerHandle and options properties will be populated.

  • scannerHandle

    string optional

    If result is SUCCESS, a handle to the scanner that can be used for further operations.

  • scannerId

    string

    The scanner ID passed to openScanner().

OperationResult

Pending

An enum that indicates the result of each operation.

Enum

"UNKNOWN"
An unknown or generic failure occurred.

"SUCCESS"
The operation succeeded.

"UNSUPPORTED"
The operation is not supported.

"CANCELLED"
The operation was cancelled.

"DEVICE_BUSY"
The device is busy.

"INVALID"
Either the data or an argument passed to the method is not valid.

"WRONG_TYPE"
The supplied value is the wrong data type for the underlying option.

"EOF"
No more data is available.

"ADF_JAMMED"
The document feeder is jammed.

"ADF_EMPTY"
The document feeder is empty.

"COVER_OPEN"
The flatbed cover is open.

"IO_ERROR"
An error occurred while communicating with the device.

"ACCESS_DENIED"
The device requires authentication.

"NO_MEMORY"
Not enough memory is available on the Chromebook to complete the operation.

"UNREACHABLE"
The device is not reachable.

"MISSING"
The device is disconnected.

"INTERNAL_ERROR"
An error has occurred somewhere other than the calling application.

OptionConstraint

Pending

Properties

  • list

    string[]|number[] optional

  • max

    number optional

  • min

    number optional

  • quant

    number optional

OptionGroup

Pending

Properties

  • members

    string[]

    An array of option names in driver-provided order.

  • title

    string

    Provides a printable title, for example "Geometry options".

OptionSetting

Pending

Properties

  • name

    string

    Indicates the name of the option to set.

  • type

    OptionType

    Indicates the data type of the option. The requested data type must match the real data type of the underlying option.

  • value

    string|number|boolean|number[] optional

    Indicates the value to set. Leave unset to request automatic setting for options that have autoSettable enabled. The data type supplied for value must match type.

OptionType

Pending

The data type of an option.

Enum

"UNKNOWN"
The option's data type is unknown. The value property will be unset.

"BOOL"
The value property will be one of truefalse.

"INT"
A signed 32-bit integer. The value property will be long or long[], depending on whether the option takes more than one value.

"FIXED"
A double in the range -32768-32767.9999 with a resolution of 1/65535. The value property will be double or double[] depending on whether the option takes more than one value. Double values that can't be exactly represented will be rounded to the available range and precision.

"STRING"
A sequence of any bytes except NUL ('\0'). The value property will be a DOMString.

"BUTTON"
An option of this type has no value. Instead, setting an option of this type causes an option-specific side effect in the scanner driver. For example, a button-typed option could be used by a scanner driver to provide a means to select default values or to tell an automatic document feeder to advance to the next sheet of paper.

"GROUP"
Grouping option. No value. This is included for compatibility, but will not normally be returned in ScannerOption values. Use getOptionGroups() to retrieve the list of groups with their member options.

OptionUnit

Pending

Indicates the data type for ScannerOption.unit.

Enum

"UNITLESS"
The value is a unitless number. For example, it can be a threshold.

"PIXEL"
The value is a number of pixels, for example, scan dimensions.

"BIT"
The value is the number of bits, for example, color depth.

"MM"
The value is measured in millimeters, for example, scan dimensions.

"DPI"
The value is measured in dots per inch, for example, resolution.

"PERCENT"
The value is a percent, for example, brightness.

"MICROSECOND"
The value is measured in microseconds, for example, exposure time.

ReadScanDataResponse

Pending

Properties

  • data

    ArrayBuffer optional

    If result is SUCCESS, contains the next chunk of scanned image data. If result is EOF, contains the last chunk of scanned image data.

  • estimatedCompletion

    number optional

    If result is SUCCESS, an estimate of how much of the total scan data has been delivered so far, in the range 0 to 100.

  • job

    string

    Provides the job handle passed to readScanData().

  • The result of reading data. If its value is SUCCESS, then data contains the next (possibly zero-length) chunk of image data that is ready for reading. If its value is EOF, the data contains the last chunk of image data.

ScannerInfo

Pending

Properties

  • connectionType

    ConnectionType

    Indicates how the scanner is connected to the computer.

  • deviceUuid

    string

    For matching against other ScannerInfo entries that point to the same physical device.

  • imageFormats

    string[]

    An array of MIME types that can be requested for returned scans.

  • manufacturer

    string

    The scanner manufacturer.

  • model

    string

    The scanner model if it is available, or a generic description.

  • name

    string

    A human-readable name for the scanner to display in the UI.

  • protocolType

    string

    A human-readable description of the protocol or driver used to access the scanner, such as Mopria, WSD, or epsonds. This is primarily useful for allowing a user to choose between protocols if a device supports multiple protocols.

  • scannerId

    string

    The ID of a specific scanner.

  • secure

    boolean

    If true, the scanner connection's transport cannot be intercepted by a passive listener, such as TLS or USB.

ScannerOption

Pending

Properties

  • configurability

    Configurability

    Indicates whether and how the option can be changed.

  • constraint

    OptionConstraint optional

    Defines OptionConstraint on the current scanner option.

  • description

    string

    A longer description of the option.

  • isActive

    boolean

    Indicates the option is active and can be set or retrieved. If false, the value property will not be set.

  • isAdvanced

    boolean

    Indicates that the UI should not display this option by default.

  • isAutoSettable

    boolean

    Can be automatically set by the scanner driver.

  • isDetectable

    boolean

    Indicates that this option can be detected from software.

  • isEmulated

    boolean

    Emulated by the scanner driver if true.

  • name

    string

    The option name using lowercase ASCII letters, numbers, and dashes. Diacritics are not allowed.

  • title

    string

    A printable one-line title.

  • type

    OptionType

    The data type contained in the value property, which is needed for setting this option.

  • unit

    OptionUnit

    The unit of measurement for this option.

  • value

    string|number|boolean|number[] optional

    The current value of the option, if relevant. Note that the data type of this property must match the data type specified in type.

ScanOptions

Properties

  • maxImages

    number optional

    The number of scanned images allowed. The default is 1.

  • mimeTypes

    string[] optional

    The MIME types that are accepted by the caller.

ScanResults

Properties

  • dataUrls

    string[]

    An array of data image URLs in a form that can be passed as the "src" value to an image tag.

  • mimeType

    string

    The MIME type of the dataUrls.

SetOptionResult

Pending

Properties

  • name

    string

    Indicates the name of the option that was set.

  • Indicates the result of setting the option.

SetOptionsResponse

Pending

Properties

  • options

    object optional

    An updated key-value mapping from option names to ScannerOption values containing the new configuration after attempting to set all supplied options. This has the same structure as the options property in OpenScannerResponse.

    This property will be set even if some options were not set successfully, but will be unset if retrieving the updated configuration fails (for example, if the scanner is disconnected in the middle of scanning).

  • results

    SetOptionResult[]

    An array of results, one each for every passed-in OptionSetting.

  • scannerHandle

    string

    Provides the scanner handle passed to setOptions().

StartScanOptions

Pending

Properties

  • format

    string

    Specifies the MIME type to return scanned data in.

  • maxReadSize

    number optional

    If a non-zero value is specified, limits the maximum scanned bytes returned in a single readScanData response to that value. The smallest allowed value is 32768 (32 KB). If this property is not specified, the size of a returned chunk may be as large as the entire scanned image.

StartScanResponse

Pending

Properties

  • job

    string optional

    If result is SUCCESS, provides a handle that can be used to read scan data or cancel the job.

  • The result of starting a scan. If the value of this is SUCCESS, the job property will be populated.

  • scannerHandle

    string

    Provides the same scanner handle that was passed to startScan().

Methods

cancelScan()

Promise Pending
chrome.documentScan.cancelScan(
  job: string,
  callback?: function,
)

Cancels a started scan and returns a Promise that resolves with a CancelScanResponse object. If a callback is used, the object is passed to it instead.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

closeScanner()

Promise Pending
chrome.documentScan.closeScanner(
  scannerHandle: string,
  callback?: function,
)

Closes the scanner with the passed in handle and returns a Promise that resolves with a CloseScannerResponse object. If a callback is used, the object is passed to it instead. Even if the response is not a success, the supplied handle becomes invalid and should not be used for further operations.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

getOptionGroups()

Promise Pending
chrome.documentScan.getOptionGroups(
  scannerHandle: string,
  callback?: function,
)

Gets the group names and member options from a scanner previously opened by openScanner. This method returns a Promise that resolves with a GetOptionGroupsResponse object. If a callback is passed to this function, returned data is passed to it instead.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

getScannerList()

Promise Pending
chrome.documentScan.getScannerList(
  filter: DeviceFilter,
  callback?: function,
)

Gets the list of available scanners and returns a Promise that resolves with a GetScannerListResponse object. If a callback is passed to this function, returned data is passed to it instead.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

openScanner()

Promise Pending
chrome.documentScan.openScanner(
  scannerId: string,
  callback?: function,
)

Opens a scanner for exclusive access and returns a Promise that resolves with an OpenScannerResponse object. If a callback is passed to this function, returned data is passed to it instead.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

readScanData()

Promise Pending
chrome.documentScan.readScanData(
  job: string,
  callback?: function,
)

Reads the next chunk of available image data from an active job handle, and returns a Promise that resolves with a ReadScanDataResponse object. If a callback is used, the object is passed to it instead.

**Note:**It is valid for a response result to be SUCCESS with a zero-length data member. This means the scanner is still working but does not yet have additional data ready. The caller should wait a short time and try again.

When the scan job completes, the response will have the result value of EOF. This response may contain a final non-zero data member.

Parameters

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

scan()

Promise 
chrome.documentScan.scan(
  options: ScanOptions,
  callback?: function,
)

Performs a document scan and returns a Promise that resolves with a ScanResults object. If a callback is passed to this function, the returned data is passed to it instead.

Parameters

  • options

    ScanOptions

    An object containing scan parameters.

  • callback

    function optional

    The callback parameter looks like: 

    (result: ScanResults)=>void

Returns

  • Promise<ScanResults>

    Chrome 96+

    Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

setOptions()

Promise Pending
chrome.documentScan.setOptions(
  scannerHandle: string,
  options: OptionSetting[],
  callback?: function,
)

Sets options on the specified scanner and returns a Promise that resolves with a SetOptionsResponse object containing the result of trying to set every value in the order of the passed-in OptionSetting object. If a callback is used, the object is passed to it instead.

Parameters

  • scannerHandle

    string

    The handle of the scanner to set options on. This should be a value previously returned from a call to openScanner.

  • options

    OptionSetting[]

    A list of OptionSetting objects to be applied to the scanner.

  • callback

    function optional

    The callback parameter looks like: 

    (response: SetOptionsResponse)=>void

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.

startScan()

Promise Pending
chrome.documentScan.startScan(
  scannerHandle: string,
  options: StartScanOptions,
  callback?: function,
)

Starts a scan on the specified scanner and returns a Promise that resolves with a StartScanResponse. If a callback is used, the object is passed to it instead. If the call was successful, the response includes a job handle that can be used in subsequent calls to read scan data or cancel a scan.

Parameters

  • scannerHandle

    string

    The handle of an open scanner. This should be a value previously returned from a call to openScanner.

  • A StartScanOptions object indicating the options to be used for the scan. The StartScanOptions.format property must match one of the entries returned in the scanner's ScannerInfo.

  • callback

    function optional

    The callback parameter looks like: 

    (response: StartScanResponse)=>void

Returns

  • Promises are only supported for Manifest V3 and later, other platforms need to use callbacks.