Android Open Source - speedofsound Volume Conversion

From Project

Back to project page speedofsound.

License

The source code is released under:

GNU General Public License

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Java Source Code

package net.codechunk.speedofsound.service;
// w  w  w . ja  v  a 2s. c  o  m
import android.content.Context;
import android.content.SharedPreferences;
import android.preference.PreferenceManager;
import android.util.Log;

import net.codechunk.speedofsound.util.AverageSpeed;

public class VolumeConversion implements SharedPreferences.OnSharedPreferenceChangeListener {
  private static final String TAG = "VolumeConversion";

  private final AverageSpeed averager = new AverageSpeed(6);
  private float lowSpeed;
  private float highSpeed;
  private int lowVolume;
  private int highVolume;

  /**
   * Convert a speed instant to a desired volume. Stateful;
   * based on previous speeds.
   */
  public float speedToVolume(float speed) {
    float volume;

    Log.v(TAG, "Pushing speed " + speed);
    this.averager.push(speed);
    float averageSpeed = this.averager.getAverage();
    Log.v(TAG, "Average currently " + averageSpeed);

    if (averageSpeed < this.lowSpeed) {
      // minimum volume
      Log.d(TAG, "Low averageSpeed triggered at " + averageSpeed);
      volume = this.lowVolume / 100f;
    } else if (averageSpeed > this.highSpeed) {
      // high volume
      Log.d(TAG, "High averageSpeed triggered at " + averageSpeed);
      volume = this.highVolume / 100f;
    } else {
      // log scaling
      float volumeRange = (this.highVolume - this.lowVolume) / 100f;
      float speedRangeFrac = (averageSpeed - this.lowSpeed) / (this.highSpeed - this.lowSpeed);
      float volumeRangeFrac = (float) (Math.log1p(speedRangeFrac) / Math.log1p(1));
      volume = this.lowVolume / 100f + volumeRange * volumeRangeFrac;
      Log.d(TAG, "Log scale triggered with " + averageSpeed + ", using volume " + volume);
    }

    return volume;
  }

  @Override
  public void onSharedPreferenceChanged(SharedPreferences prefs, String s) {
    this.lowSpeed = prefs.getFloat("low_speed", 0);
    this.lowVolume = prefs.getInt("low_volume", 0);
    this.highSpeed = prefs.getFloat("high_speed", 100);
    this.highVolume = prefs.getInt("high_volume", 100);
  }

}

Java Source Code List