MLKitDigitalInkRecognition Framework Reference

  • This documentation details globally available classes for digital ink recognition within ML Kit.

  • These classes provide functionality for recognizing handwritten text from user input, including representing ink strokes, managing recognition models, and handling recognition results.

  • MLKDigitalInkRecognizer is the core class used to perform the recognition, utilizing models like MLKDigitalInkRecognitionModel and options defined by MLKDigitalInkRecognizerOptions.

  • Input is represented by MLKInk, comprising of MLKStroke objects made up of MLKStrokePoint instances, while MLKDigitalInkRecognitionResult encapsulates the recognition output with candidate interpretations (MLKDigitalInkRecognitionCandidate).

  • MLKDigitalInkRecognitionContext provides contextual information for improved recognition, and MLKWritingArea defines properties of the user's writing space.

Classes

The following classes are available globally.

  • Individual recognition candidate.

    A recognizer usually provides several recognition alternatives. This object represents one such alternative.

    See DigitalInkRecognitionResult for more details.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognitionCandidate : NSObject

  • Information about the context in which an ink has been drawn.

    Pass this object to a DigitalInkRecognizer alongside an ink to improve the recognition quality.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognitionContext : NSObject

  • Represents a downloadable recognition model.

    Recognition models are downloaded on the device when the download method is called. The downloaded model is unzipped when DigitalInkRecognizer loads it at inference time for the first time, which makes the first recognition a bit slower than subsequent ones.

    This object contains properties that are constant throughout the lifetime of a recognition model.

    See DigitalInkRecognitionContext for the properties that depend on the ink being recognized.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognitionModel : MLKRemoteModel

  • Represents a digital ink recognition model specific to a language, script, and optionally a regional variant.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognitionModelIdentifier : NSObject

  • Object representing the output of an ink recognition.

    A recognizer usually provides several recognition alternatives, because the user intent is not always clear. For example, if the user writes a vertical line and then a circle, the recognition alternatives could include “10”, “IO”, and “lo”.

    Alternatives are named “candidates”. This object represents a set of candidates as a list of DigitalInkRecognitionCandidate.

    Use DigitalInkRecognizer to perform the recognition itself. If nothing could be recognized, the property candidates will be an empty array.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognitionResult : NSObject

  • Object to perform handwriting recognition on digital ink.

    Digital ink is the vector representation of what a user has written. It is composed of a sequence of strokes, each being a sequence of touch points (coordinates and timestamp). See Ink for details.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognizer : NSObject

  • Options defining the behavior of a DigitalInkRecognizer.

    Declaration

    Objective-C

    
@interface MLKDigitalInkRecognizerOptions : NSObject

  • A single touch point from the user.

    Declaration

    Objective-C

    
@interface MLKStrokePoint : NSObject

  • Represents a sequence of touch points between a pen (resp. touch) down and pen (resp. touch) up event.

    Declaration

    Objective-C

    
@interface MLKStroke : NSObject

  • Represents the user input as a collection of Stroke and serves as input for the handwriting recognition task.

    Declaration

    Objective-C

    
@interface MLKInk : NSObject

  • A model that is stored remotely on the server and downloaded to the device.

    Declaration

    Objective-C

    
@interface MLKRemoteModel : NSObject

  • Properties of the writing area.

    The writing area is the area on the screen where the user can draw an ink.

    Declaration

    Objective-C

    
@interface MLKWritingArea : NSObject