Generate negative image using ColorMatrix

Last exercise demonstrate "how to use ColorMatrix to change Bitmap". With a suitable ColorMatrix assigned to ColorMatrixColorFilter(), we can generate negative image easily.

Modify onDraw() method of MyView.java in last exercise.

 @Override
 protected void onDraw(Canvas canvas) {
  
  //To generate negative image
  float[] colorMatrix_Negative = { 
    -1.0f, 0, 0, 0, 255, //red
    0, -1.0f, 0, 0, 255, //green
    0, 0, -1.0f, 0, 255, //blue
    0, 0, 0, 1.0f, 0 //alpha  
  };
  
  Paint MyPaint_Normal = new Paint();
  Paint MyPaint_Negative = new Paint();
  ColorFilter colorFilter_Negative = new ColorMatrixColorFilter(colorMatrix_Negative);
  MyPaint_Negative.setColorFilter(colorFilter_Negative);
     
     Bitmap myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
     canvas.drawBitmap(myBitmap, 400, 100, MyPaint_Normal);
     canvas.drawBitmap(myBitmap, 500, 100, MyPaint_Negative);
 };

Download the files.