MLKitDigitalInkRecognition Framework Reference

  • StrokePoint represents a single touch point from the user, containing horizontal (x), vertical (y) coordinates, and optionally a timestamp (t).

  • Coordinates are in arbitrary but consistent scales, where a unit change in x and y represents the same physical distance.

  • Timestamp t is recorded in milliseconds and represents the time the point was captured.

  • StrokePoint can be initialized with or without a timestamp, but including timestamps is recommended for better recognition accuracy.

  • When initializing, spatial origins can be arbitrary but must remain consistent for all points within the same ink.

StrokePoint

class StrokePoint : NSObject

A single touch point from the user.

  • x

    Horizontal coordinate. Increases to the right.

    Declaration

    Swift

    var x: Float { get }

  • y

    Vertical coordinate. Increases downward.

    Declaration

    Swift

    var y: Float { get }

  • t

    Time when the point was recorded, in milliseconds.

    Declaration

    Swift

    var t: NSNumber? { get }

  • Unavailable. Use init(x:y:t:) instead.

  • Creates a StrokePoint object using the coordinates provided as argument.

    Scales on both dimensions are arbitrary but be must be identical: a displacement of 1 horizontally or vertically must represent the same distance, as seen by the user.

    Spatial and temporal origins can be arbitrary as long as they are consistent for a given ink.

    Declaration

    Swift

    init(x: Float, y: Float, t: Int)

    Parameters

    x

    Horizontal coordinate. Increases to the right.
    y

    Vertical coordinate. Increases going downward.
    t

    Time when the point was recorded, in milliseconds.

  • Creates a StrokePoint object using the coordinates provided as argument, without specifying a timestamp. This method should only be used when it is not feasible to include the timestamp information, as the recognition accuracy might degrade.

    Scales on both dimensions are arbitrary but be must be identical: a displacement of 1 horizontally or vertically must represent the same distance, as seen by the user.

    Spatial origin can be arbitrary as long as it is consistent for a given ink.

    Declaration

    Swift

    init(x: Float, y: Float)

    Parameters

    x

    horizontal coordinate. Increases to the right.
    y

    vertical coordinate. Increases going downward.