Package icyllis.modernui.view

Class VelocityTracker.Estimator

java.lang.Object
icyllis.modernui.view.VelocityTracker.Estimator
Enclosing class:
VelocityTracker
@Internal public static final class VelocityTracker.Estimator extends Object
An estimator for the movements of a pointer based on a polynomial model.

The last recorded position of the pointer is at time zero seconds. Past estimated positions are at negative times and future estimated positions are at positive times.

First coefficient is position (in pixels), second is velocity (in pixels per second), third is acceleration (in pixels per second squared).

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    float
    confidence
    Confidence (coefficient of determination), between 0 (no fit) and 1 (perfect fit).
    int
    degree
    Polynomial degree, or zero if only position information is available.
    long
    time
    Estimator time base, in nanoseconds.
    final float[]
    xCoeff
    Polynomial coefficients describing motion in X.
    final float[]
    yCoeff
    Polynomial coefficients describing motion in Y.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Estimator()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    clear()
     
    float
    estimateX(float time)
    Gets an estimate of the X position of the pointer at the specified time point.
    float
    estimateY(float time)
    Gets an estimate of the Y position of the pointer at the specified time point.
    float
    getXCoeff(int index)
    Gets the X coefficient with the specified index.
    float
    getYCoeff(int index)
    Gets the Y coefficient with the specified index.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • time

      public long time
      Estimator time base, in nanoseconds.

    • xCoeff

      public final float[] xCoeff
      Polynomial coefficients describing motion in X.

    • yCoeff

      public final float[] yCoeff
      Polynomial coefficients describing motion in Y.

    • degree

      public int degree
      Polynomial degree, or zero if only position information is available.

    • confidence

      public float confidence
      Confidence (coefficient of determination), between 0 (no fit) and 1 (perfect fit).

  • Constructor Details

    • Estimator

      public Estimator()

  • Method Details

    • estimateX

      public float estimateX(float time)
      Gets an estimate of the X position of the pointer at the specified time point.
      Parameters:
      time - The time point in seconds, 0 is the last recorded time.
      Returns:
      The estimated X coordinate.

    • estimateY

      public float estimateY(float time)
      Gets an estimate of the Y position of the pointer at the specified time point.
      Parameters:
      time - The time point in seconds, 0 is the last recorded time.
      Returns:
      The estimated Y coordinate.

    • getXCoeff

      public float getXCoeff(int index)
      Gets the X coefficient with the specified index.
      Parameters:
      index - The index of the coefficient to return.
      Returns:
      The X coefficient, or 0 if the index is greater than the degree.

    • getYCoeff

      public float getYCoeff(int index)
      Gets the Y coefficient with the specified index.
      Parameters:
      index - The index of the coefficient to return.
      Returns:
      The Y coefficient, or 0 if the index is greater than the degree.

    • clear

      public void clear()