title: android colormatrix for black color
body: <p>I am using following code to make my picture black</p>
  
  <pre><code>BitmapDrawable bdarw = new BitmapDrawable(imagePath);
  
                  ColorMatrix cm = new ColorMatrix();
                  cm.set(new float[] {
                          2, 1f, 0, 0, 0, 
                          0, 2, 0f, 0, 0,
                          0, 0, 2, 0f, 0, 
                          0, 0, 0, 1f, 0 });
  
                  bdarw.setColorFilter(new ColorMatrixColorFilter(cm));
  
                  Bitmap bitmap= bdarw.getBitmap();
  
                  ImageView imageView = (ImageView) findViewById(R.id.imgV);
                  imageView.setImageBitmap(bitmap);
  </code></pre>
  
  <p>but it seems color matrix is not correct can you please help me out</p>