Logo Questions Linux Laravel Mysql Ubuntu Git Menu
 

Understanding the Use of ColorMatrix and ColorMatrixColorFilter to Modify a Drawable's Hue

This is what I use for my game. This is the compilation of various part found on various articles on websites. Credits goes to the original author from the @see links. Note that a lot more can be done with color matrices. Including inverting, etc...

public class ColorFilterGenerator
{
    /**
 * 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 adjustHue( float value )
{
    ColorMatrix cm = new ColorMatrix();

    adjustHue(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 adjustHue(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));
}
}

To complete this I should add an example:

ImageView Sun = (ImageView)findViewById(R.id.sun);
Sun.setColorFilter(ColorFilterGenerator.adjustHue(162)); // 162 degree rotation

here is the complete code if you want to adjust the bright, contrast, saturation and hue. Enjoy! Thanks a lot to @RichardLalancette

public class ColorFilterGenerator {

private static double DELTA_INDEX[] = {
    0,    0.01, 0.02, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1,  0.11,
    0.12, 0.14, 0.15, 0.16, 0.17, 0.18, 0.20, 0.21, 0.22, 0.24,
    0.25, 0.27, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42,
    0.44, 0.46, 0.48, 0.5,  0.53, 0.56, 0.59, 0.62, 0.65, 0.68, 
    0.71, 0.74, 0.77, 0.80, 0.83, 0.86, 0.89, 0.92, 0.95, 0.98,
    1.0,  1.06, 1.12, 1.18, 1.24, 1.30, 1.36, 1.42, 1.48, 1.54,
    1.60, 1.66, 1.72, 1.78, 1.84, 1.90, 1.96, 2.0,  2.12, 2.25, 
    2.37, 2.50, 2.62, 2.75, 2.87, 3.0,  3.2,  3.4,  3.6,  3.8,
    4.0,  4.3,  4.7,  4.9,  5.0,  5.5,  6.0,  6.5,  6.8,  7.0,
    7.3,  7.5,  7.8,  8.0,  8.4,  8.7,  9.0,  9.4,  9.6,  9.8, 
    10.0
};

/**
 * @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 adjustHue(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));
}

public static void adjustBrightness(ColorMatrix cm, float value) {
    value = cleanValue(value,100);
    if (value == 0) {
        return;
    }

    float[] mat = new float[]
    { 
        1,0,0,0,value,
        0,1,0,0,value,
        0,0,1,0,value,
        0,0,0,1,0,
        0,0,0,0,1
    };
    cm.postConcat(new ColorMatrix(mat));
}

public static void adjustContrast(ColorMatrix cm, int value) {
    value = (int)cleanValue(value,100);
    if (value == 0) { 
        return; 
    }
    float x;
    if (value < 0) {
        x = 127 + (float) value / 100*127;
    } else {
        x = value % 1;
        if (x == 0) {
            x = (float)DELTA_INDEX[value];
        } else {
            //x = DELTA_INDEX[(p_val<<0)]; // this is how the IDE does it.
            x = (float)DELTA_INDEX[(value<<0)]*(1-x) + (float)DELTA_INDEX[(value<<0)+1] * x; // use linear interpolation for more granularity.
        }
        x = x*127+127;
    }

    float[] mat = new float[]
    { 
            x/127,0,0,0, 0.5f*(127-x),
            0,x/127,0,0, 0.5f*(127-x),
            0,0,x/127,0, 0.5f*(127-x),
            0,0,0,1,0,
            0,0,0,0,1
    };
    cm.postConcat(new ColorMatrix(mat));

}

public static void adjustSaturation(ColorMatrix cm, float value) {
    value = cleanValue(value,100);
    if (value == 0) {
        return;
    }

    float x = 1+((value > 0) ? 3 * value / 100 : value / 100);
    float lumR = 0.3086f;
    float lumG = 0.6094f;
    float lumB = 0.0820f;

    float[] mat = new float[]
    { 
        lumR*(1-x)+x,lumG*(1-x),lumB*(1-x),0,0,
        lumR*(1-x),lumG*(1-x)+x,lumB*(1-x),0,0,
        lumR*(1-x),lumG*(1-x),lumB*(1-x)+x,0,0,
        0,0,0,1,0,
        0,0,0,0,1
    };
    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));
}

public static ColorFilter adjustColor(int brightness, int contrast, int saturation, int hue){
    ColorMatrix cm = new ColorMatrix();
    adjustHue(cm, hue);
    adjustContrast(cm, contrast);
    adjustBrightness(cm, brightness);
    adjustSaturation(cm, saturation);

    return new ColorMatrixColorFilter(cm);
}
}

For anyone who is interested in how to use the ColorMatrixColorFilter. The sample I used here, converted every pixel into red when I draw the bitmap on the canvas.

The comment in the class is from: http://developer.android.com/reference/android/graphics/ColorMatrix.html this gives you some insights on how this is working

@Override
protected void onDraw(Canvas canvas) {

    // The matrix is stored in a single array, and its treated as follows: [ a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t ]
    // When applied to a color [r, g, b, a], the resulting color is computed as (after clamping) ;
    //   R' = a*R + b*G + c*B + d*A + e; 
    //   G' = f*R + g*G + h*B + i*A + j; 
    //   B' = k*R + l*G + m*B + n*A + o; 
    //   A' = p*R + q*G + r*B + s*A + t; 

    Paint paint = new Paint();
    float[] matrix = { 
        1, 1, 1, 1, 1, //red
        0, 0, 0, 0, 0, //green
        0, 0, 0, 0, 0, //blue
        1, 1, 1, 1, 1 //alpha
    };
    paint.setColorFilter(new ColorMatrixColorFilter(matrix));

    Rect source = new Rect(0, 0, 100, 100);
    Rect dest = new Rect(0, 0, 100, 100);

    Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.sampleimage);
    canvas.drawBitmap(bitmap , source, dest, paint);
}

The below class is an improvement on the answers that have already been posted. This makes it easier to read and create a ColorFilter from a Bitmap.

Example usage:

ImageView imageView = ...;
Drawable drawable = imageView.getDrawable();
ColorFilter colorFilter = ColorFilterGenerator.from(drawable).to(Color.RED);
imageView.setColorFilter(colorFilter);

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorFilter;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.graphics.drawable.PictureDrawable;
import android.widget.ImageView;

/**
 * Creates a {@link ColorMatrixColorFilter} to adjust the hue, saturation, brightness, or
 * contrast of an {@link Bitmap}, {@link Drawable}, or {@link ImageView}.
 * <p/>
 * Example usage:
 * <br/>
 * {@code imageView.setColorFilter(ColorFilterGenerator.from(Color.BLUE).to(Color.RED));}
 *
 * @author Jared Rummler <[email protected]>
 */
public class ColorFilterGenerator {

  // Based off answer from StackOverflow
  // See: http://stackoverflow.com/a/15119089/1048340

  private ColorFilterGenerator() {
    throw new AssertionError();
  }

  public static From from(Drawable drawable) {
    return new From(drawableToBitmap(drawable));
  }

  public static From from(Bitmap bitmap) {
    return new From(bitmap);
  }

  public static From from(int color) {
    return new From(color);
  }

  // --------------------------------------------------------------------------------------------

  private static final double DELTA_INDEX[] = {
      0, 0.01, 0.02, 0.04, 0.05, 0.06, 0.07, 0.08, 0.1, 0.11, 0.12, 0.14, 0.15, 0.16, 0.17, 0.18,
      0.20, 0.21, 0.22, 0.24, 0.25, 0.27, 0.28, 0.30, 0.32, 0.34, 0.36, 0.38, 0.40, 0.42, 0.44,
      0.46, 0.48, 0.5, 0.53, 0.56, 0.59, 0.62, 0.65, 0.68, 0.71, 0.74, 0.77, 0.80, 0.83, 0.86, 0.89,
      0.92, 0.95, 0.98, 1.0, 1.06, 1.12, 1.18, 1.24, 1.30, 1.36, 1.42, 1.48, 1.54, 1.60, 1.66, 1.72,
      1.78, 1.84, 1.90, 1.96, 2.0, 2.12, 2.25, 2.37, 2.50, 2.62, 2.75, 2.87, 3.0, 3.2, 3.4, 3.6,
      3.8, 4.0, 4.3, 4.7, 4.9, 5.0, 5.5, 6.0, 6.5, 6.8, 7.0, 7.3, 7.5, 7.8, 8.0, 8.4, 8.7, 9.0, 9.4,
      9.6, 9.8, 10.0
  };

  public static void adjustHue(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));
  }

  public static void adjustBrightness(ColorMatrix cm, float value) {
    value = cleanValue(value, 100);
    if (value == 0) {
      return;
    }

    float[] mat = new float[]{
        1, 0, 0, 0, value, 0, 1, 0, 0, value, 0, 0, 1, 0, value, 0, 0, 0, 1, 0, 0, 0, 0, 0,
        1
    };
    cm.postConcat(new ColorMatrix(mat));
  }

  public static void adjustContrast(ColorMatrix cm, int value) {
    value = (int) cleanValue(value, 100);
    if (value == 0) {
      return;
    }
    float x;
    if (value < 0) {
      x = 127 + value / 100 * 127;
    } else {
      x = value % 1;
      if (x == 0) {
        x = (float) DELTA_INDEX[value];
      } else {
        x = (float) DELTA_INDEX[(value << 0)] * (1 - x)
            + (float) DELTA_INDEX[(value << 0) + 1] * x;
      }
      x = x * 127 + 127;
    }

    float[] mat = new float[]{
        x / 127, 0, 0, 0, 0.5f * (127 - x), 0, x / 127, 0, 0, 0.5f * (127 - x), 0, 0,
        x / 127, 0, 0.5f * (127 - x), 0, 0, 0, 1, 0, 0, 0, 0, 0, 1
    };
    cm.postConcat(new ColorMatrix(mat));

  }

  public static void adjustSaturation(ColorMatrix cm, float value) {
    value = cleanValue(value, 100);
    if (value == 0) {
      return;
    }

    float x = 1 + ((value > 0) ? 3 * value / 100 : value / 100);
    float lumR = 0.3086f;
    float lumG = 0.6094f;
    float lumB = 0.0820f;

    float[] mat = new float[]{
        lumR * (1 - x) + x, lumG * (1 - x), lumB * (1 - x), 0, 0, lumR * (1 - x),
        lumG * (1 - x) + x, lumB * (1 - x), 0, 0, lumR * (1 - x), lumG * (1 - x),
        lumB * (1 - x) + x, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1
    };
    cm.postConcat(new ColorMatrix(mat));
  }

  // --------------------------------------------------------------------------------------------

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

  private static float[] getHsv(int color) {
    float[] hsv = new float[3];
    Color.RGBToHSV(Color.red(color), Color.green(color), Color.blue(color), hsv);
    return hsv;
  }

  /**
   * Converts a {@link Drawable} to a {@link Bitmap}
   *
   * @param drawable
   *     The {@link Drawable} to convert
   * @return The converted {@link Bitmap}.
   */
  private static Bitmap drawableToBitmap(Drawable drawable) {
    if (drawable instanceof BitmapDrawable) {
      return ((BitmapDrawable) drawable).getBitmap();
    } else if (drawable instanceof PictureDrawable) {
      PictureDrawable pictureDrawable = (PictureDrawable) drawable;
      Bitmap bitmap = Bitmap.createBitmap(pictureDrawable.getIntrinsicWidth(),
          pictureDrawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
      Canvas canvas = new Canvas(bitmap);
      canvas.drawPicture(pictureDrawable.getPicture());
      return bitmap;
    }
    int width = drawable.getIntrinsicWidth();
    width = width > 0 ? width : 1;
    int height = drawable.getIntrinsicHeight();
    height = height > 0 ? height : 1;
    Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
    drawable.draw(canvas);
    return bitmap;
  }

  /**
   * Calculate the average red, green, blue color values of a bitmap
   *
   * @param bitmap
   *     a {@link Bitmap}
   * @return
   */
  private static int[] getAverageColorRGB(Bitmap bitmap) {
    int width = bitmap.getWidth();
    int height = bitmap.getHeight();
    int size = width * height;
    int[] pixels = new int[size];
    int r, g, b;
    r = g = b = 0;
    bitmap.getPixels(pixels, 0, width, 0, 0, width, height);
    for (int i = 0; i < size; i++) {
      int pixelColor = pixels[i];
      if (pixelColor == Color.TRANSPARENT) {
        size--;
        continue;
      }
      r += Color.red(pixelColor);
      g += Color.green(pixelColor);
      b += Color.blue(pixelColor);
    }
    r /= size;
    g /= size;
    b /= size;
    return new int[]{
        r, g, b
    };
  }

  /**
   * Calculate the average color value of a bitmap
   *
   * @param bitmap
   *     a {@link Bitmap}
   * @return
   */
  private static int getAverageColor(Bitmap bitmap) {
    int[] rgb = getAverageColorRGB(bitmap);
    return Color.argb(255, rgb[0], rgb[1], rgb[2]);
  }

  // Builder
  // --------------------------------------------------------------------------------------------

  public static final class Builder {

    int hue;

    int contrast;

    int brightness;

    int saturation;

    public Builder setHue(int hue) {
      this.hue = hue;
      return this;
    }

    public Builder setContrast(int contrast) {
      this.contrast = contrast;
      return this;
    }

    public Builder setBrightness(int brightness) {
      this.brightness = brightness;
      return this;
    }

    public Builder setSaturation(int saturation) {
      this.saturation = saturation;
      return this;
    }

    public ColorFilter build() {
      ColorMatrix cm = new ColorMatrix();
      adjustHue(cm, hue);
      adjustContrast(cm, contrast);
      adjustBrightness(cm, brightness);
      adjustSaturation(cm, saturation);
      return new ColorMatrixColorFilter(cm);
    }
  }

  public static final class From {

    final int oldColor;

    private From(Bitmap bitmap) {
      oldColor = getAverageColor(bitmap);
    }

    private From(int oldColor) {
      this.oldColor = oldColor;
    }

    public ColorFilter to(int newColor) {
      float[] hsv1 = getHsv(oldColor);
      float[] hsv2 = getHsv(newColor);
      int hue = (int) (hsv2[0] - hsv1[0]);
      int saturation = (int) (hsv2[1] - hsv1[1]);
      int brightness = (int) (hsv2[2] - hsv1[2]);
      return new ColorFilterGenerator.Builder()
          .setHue(hue)
          .setSaturation(saturation)
          .setBrightness(brightness)
          .build();
    }
  }

}

There is no linear relationship between Hue and RGB. Hue is defined piecewise in 60° chunks (http://en.wikipedia.org/wiki/HSL_color_space#General_approach), and therefore there is not a simple matrix conversion between HSV and RGB. To change the hue of an image, you can use the following method :

public Bitmap changeHue( Bitmap source, double hue ) {
    Bitmap result = Bitmap.createBitmap( source.getWidth(), source.getHeight(), source.getConfig() );

    float[] hsv = new float[3];
    for( int x = 0; x < source.getWidth(); x++ ) {
        for( int y = 0; y < source.getHeight(); y++ ) {
            int c = source.getPixel( x, y );
            Color.colorToHSV( c, hsv );
            hsv[0] = (float) ((hsv[0] + 360 * hue) % 360);
            c = (Color.HSVToColor( hsv ) & 0x00ffffff) | (c & 0xff000000);
            result.setPixel( x, y, c );
        }
    }

    return result;
}

I think this method will give you what you want:

http://android.okhelp.cz/hue-color-colored-filter-bitmap-image-android-example/

bitmapOrg.setColorFilter(Color.RED, PorterDuff.Mode.MULTIPLY);