GestureUtils

Kotlin |Java

class GestureUtils

kotlin.Any
↳	android.gesture.GestureUtils

Utility functions for gesture processing & analysis, including methods for:

feature extraction (e.g., samplers and those for calculating bounding boxes and gesture path lengths);
geometric transformation (e.g., translation, rotation and scaling);
gesture similarity comparison (e.g., calculating Euclidean or Cosine distances between two gestures).

Summary

Public methods
static OrientedBoundingBox!	`computeOrientedBoundingBox(originalPoints: ArrayList<GesturePoint!>!)` Computes an oriented, minimum bounding box of a set of points.
static OrientedBoundingBox!	`computeOrientedBoundingBox(originalPoints: FloatArray!)` Computes an oriented, minimum bounding box of a set of points.
static FloatArray!	`spatialSampling(gesture: Gesture!, bitmapSize: Int)` Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap.
static FloatArray!	`spatialSampling(gesture: Gesture!, bitmapSize: Int, keepAspectRatio: Boolean)` Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap.
static FloatArray!	`temporalSampling(stroke: GestureStroke!, numPoints: Int)` Samples a stroke temporally into a given number of evenly-distributed points.

Public methods

computeOrientedBoundingBox

Added in API level 8

static fun computeOrientedBoundingBox(originalPoints: ArrayList<GesturePoint!>!): OrientedBoundingBox!

Computes an oriented, minimum bounding box of a set of points.

Parameters
`originalPoints`	ArrayList<GesturePoint!>!:

Return
`OrientedBoundingBox!`	an oriented bounding box

computeOrientedBoundingBox

Added in API level 8

static fun computeOrientedBoundingBox(originalPoints: FloatArray!): OrientedBoundingBox!

Computes an oriented, minimum bounding box of a set of points.

Parameters
`originalPoints`	FloatArray!:

Return
`OrientedBoundingBox!`	an oriented bounding box

spatialSampling

Added in API level 8

static fun spatialSampling(
    gesture: Gesture!, 
    bitmapSize: Int
): FloatArray!

Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap. Scales the gesture to fit the size of the bitmap. The scaling does not necessarily keep the aspect ratio of the gesture.

Parameters
`gesture`	Gesture!: the gesture to be sampled
`bitmapSize`	Int: the size of the bitmap

Return
`FloatArray!`	a bitmapSize x bitmapSize grayscale bitmap that is represented as a 1D array. The float at index i represents the grayscale value at pixel [i%bitmapSize, i/bitmapSize]

spatialSampling

Added in API level 8

static fun spatialSampling(
    gesture: Gesture!, 
    bitmapSize: Int, 
    keepAspectRatio: Boolean
): FloatArray!

Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap. Scales the gesture to fit the size of the bitmap.

Parameters
`gesture`	Gesture!: the gesture to be sampled
`bitmapSize`	Int: the size of the bitmap
`keepAspectRatio`	Boolean: if the scaling should keep the gesture's aspect ratio

Return
`FloatArray!`	a bitmapSize x bitmapSize grayscale bitmap that is represented as a 1D array. The float at index i represents the grayscale value at pixel [i%bitmapSize, i/bitmapSize]

temporalSampling

Added in API level 8

static fun temporalSampling(
    stroke: GestureStroke!, 
    numPoints: Int
): FloatArray!

Samples a stroke temporally into a given number of evenly-distributed points.

Parameters
`stroke`	GestureStroke!: the gesture stroke to be sampled
`numPoints`	Int: the number of points

Return
`FloatArray!`	the sampled points in the form of [x1, y1, x2, y2, ..., xn, yn]