NewPipe/app/src/main/java/org/schabi/newpipe/player/helper/PlayerSemitoneHelper.java

41 lines
1.3 KiB
Java

package org.schabi.newpipe.player.helper;
import androidx.core.math.MathUtils;
/**
* Converts between percent and 12-tone equal temperament semitones.
* <br/>
* @see
* <a href="https://en.wikipedia.org/wiki/Equal_temperament#Twelve-tone_equal_temperament">
* Wikipedia: Equal temperament#Twelve-tone equal temperament
* </a>
*/
public final class PlayerSemitoneHelper {
public static final int SEMITONE_COUNT = 12;
private PlayerSemitoneHelper() {
// No impl
}
public static String formatPitchSemitones(final double percent) {
return formatPitchSemitones(percentToSemitones(percent));
}
public static String formatPitchSemitones(final int semitones) {
return semitones > 0 ? "+" + semitones : "" + semitones;
}
public static double semitonesToPercent(final int semitones) {
return Math.pow(2, ensureSemitonesInRange(semitones) / (double) SEMITONE_COUNT);
}
public static int percentToSemitones(final double percent) {
return ensureSemitonesInRange(
(int) Math.round(SEMITONE_COUNT * Math.log(percent) / Math.log(2)));
}
private static int ensureSemitonesInRange(final int semitones) {
return MathUtils.clamp(semitones, -SEMITONE_COUNT, SEMITONE_COUNT);
}
}