HsvEvaluator.java

package uk.co.cogitolearning.propertyanimations_example;

import android.animation.TypeEvaluator;
import android.graphics.Color;

public class HsvEvaluator implements TypeEvaluator<Integer>
{
  
  @Override
  public Integer evaluate(float fraction, Integer startValue, Integer endValue)
  {
    float[] startHsv = new float[3];
    float[] endHsv = new float[3];
    float[] currentHsv = new float[3];
    
    Color.colorToHSV(startValue, startHsv);
    Color.colorToHSV(endValue, endHsv);
    
    for (int i=0; i<3; i++)
      currentHsv[i] = (1-fraction)*startHsv[i] + fraction*endHsv[i];

    while (currentHsv[0]>=360.0f) currentHsv[0] -= 360.0f;
    while (currentHsv[0]<0.0f) currentHsv[0] += 360.0f;
    
    return Color.HSVToColor(currentHsv);
  }

}