Android Open Source - Resonos-Android-Framework Hue Color Filter

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License

The source code is released under:

Apache License

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Java Source Code

package com.resonos.apps.library.media;
//from   www .j av a  2s  .c  om
import android.graphics.ColorFilter;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;

/**
 * For creating a color filter to set the hue of a drawable.
 * From http://stackoverflow.com/questions/4354939/understanding-the-use-of-colormatrix-and-colormatrixcolorfilter-to-modify-a-draw
 */
public class HueColorFilter {
  /**
   * Creates a HUE ajustment ColorFilter
   * 
   * @see http
   *      ://groups.google.com/group/android-developers/browse_thread/thread
   *      /9e215c83c3819953
   * @see http://gskinner.com/blog/archives/2007/12/colormatrix_cla.html
   * @param value
   *            degrees to shift the hue.
   * @return
   */
  public static ColorFilter create(float value) {
    ColorMatrix cm = new ColorMatrix();

    create(cm, value);

    return new ColorMatrixColorFilter(cm);
  }

  /**
   * @see http
   *      ://groups.google.com/group/android-developers/browse_thread/thread
   *      /9e215c83c3819953
   * @see http://gskinner.com/blog/archives/2007/12/colormatrix_cla.html
   * @param cm
   * @param value
   */
  public static void create(ColorMatrix cm, float value) {
    value = cleanValue(value, 180f) / 180f * (float) Math.PI;
    if (value == 0) {
      return;
    }
    float cosVal = (float) Math.cos(value);
    float sinVal = (float) Math.sin(value);
    float lumR = 0.213f;
    float lumG = 0.715f;
    float lumB = 0.072f;
    float[] mat = new float[] {
        lumR + cosVal * (1 - lumR) + sinVal * (-lumR),
        lumG + cosVal * (-lumG) + sinVal * (-lumG),
        lumB + cosVal * (-lumB) + sinVal * (1 - lumB), 0, 0,
        lumR + cosVal * (-lumR) + sinVal * (0.143f),
        lumG + cosVal * (1 - lumG) + sinVal * (0.140f),
        lumB + cosVal * (-lumB) + sinVal * (-0.283f), 0, 0,
        lumR + cosVal * (-lumR) + sinVal * (-(1 - lumR)),
        lumG + cosVal * (-lumG) + sinVal * (lumG),
        lumB + cosVal * (1 - lumB) + sinVal * (lumB), 0, 0, 0f, 0f, 0f,
        1f, 0f, 0f, 0f, 0f, 0f, 1f };
    cm.postConcat(new ColorMatrix(mat));
  }

  protected static float cleanValue(float p_val, float p_limit) {
    return Math.min(p_limit, Math.max(-p_limit, p_val));
  }
}

Java Source Code List