GestureUtils

Kotlin |Java

public final class GestureUtils
extends Object

java.lang.Object
↳	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(ArrayList<GesturePoint> originalPoints)` Computes an oriented, minimum bounding box of a set of points.
`static OrientedBoundingBox`	`computeOrientedBoundingBox(float[] originalPoints)` Computes an oriented, minimum bounding box of a set of points.
`static float[]`	`spatialSampling(Gesture gesture, int bitmapSize)` Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap.
`static float[]`	`spatialSampling(Gesture gesture, int bitmapSize, boolean keepAspectRatio)` Samples the gesture spatially by rendering the gesture into a 2D grayscale bitmap.
`static float[]`	`temporalSampling(GestureStroke stroke, int numPoints)` Samples a stroke temporally into a given number of evenly-distributed points.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public methods

computeOrientedBoundingBox

Added in API level 8

public static OrientedBoundingBox computeOrientedBoundingBox (ArrayList<GesturePoint> originalPoints)

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

Returns
`OrientedBoundingBox`	an oriented bounding box

computeOrientedBoundingBox

Added in API level 8

public static OrientedBoundingBox computeOrientedBoundingBox (float[] originalPoints)

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

Returns
`OrientedBoundingBox`	an oriented bounding box

spatialSampling

Added in API level 8

public static float[] spatialSampling (Gesture gesture, 
                int bitmapSize)

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

Returns
`float[]`	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

public static float[] spatialSampling (Gesture gesture, 
                int bitmapSize, 
                boolean keepAspectRatio)

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

Returns
`float[]`	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

public static float[] temporalSampling (GestureStroke stroke, 
                int numPoints)

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

Returns
`float[]`	the sampled points in the form of [x1, y1, x2, y2, ..., xn, yn]