Code snippet to manipulate the brightness of an image in Android

gistfile1.txt

// It's assumed this function is defined in a class extending 'ImageView'
void addEffectBrightness(){
  float brightness = mBrightnessValue;
	mCm = new ColorMatrix();
	
mCm.set(new float[] { 1, 0, 0, 0, brightness,
		0, 1, 0, 0,brightness,
		0, 0, 1, 0, brightness,
		0, 0, 0, 1, 0 });
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setColorFilter(new ColorMatrixColorFilter(mCm));
mCm = null;
}
redraw(mPaint); //the redraw func here should refresh the screen canvas
}

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

/*The brighness value can be changed and the effect viewed in realtime by 
implementing android.widget.SeekBar.OnSeekBarChangeListener and refreshing(invalidate()) 
the cavas each time its changed */