title: draw text on top of bitmap failed
body: <p>I want to display a point and a text on top of an image. I have tried several tutorial on overlaying bitmap, but it doesn't seem to work. Here is the code which displays the background image.</p>
  
  <pre><code>mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.roomplan);
  mIV = (ImageView)findViewById(R.id.ImageView01);
  mIV.setImageBitmap(mBitmap); 
  mIV.invalidate();
  
  btnDraw = (Button)findViewById(R.id.Button01);
  btnDraw.setOnClickListener(this);
  </code></pre>
  
  <p>Then on the OnClickListener, I define another bitmap and draw the point and the text.</p>
  
  <pre><code>Bitmap bmOverlay = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), 
      Bitmap.Config.ARGB_4444);
  Canvas canvas = new Canvas(bmOverlay);
  Paint paint = new Paint();
  paint.setColor(Color.CYAN);
  paint.setTextSize(20);
  paint.setFlags(Paint.ANTI_ALIAS_FLAG);
  canvas.drawText("You are here", 100, 100, paint);
  canvas.drawPoint(30.0f, 50.0f, paint);
  canvas.drawBitmap(bmOverlay, 0, 0, null);
  </code></pre>
  
  <p>Nothing is displayed on top of the background image, even when I remove the image. Any hint please?</p>
  
  <p><strong>Update:</strong> The working code</p>
  
  <pre><code>// get a reference to the background image
  mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.raumplan_isst);
  
  mIV = (ImageView)findViewById(R.id.ImageView01);
  
  // create a mutable bitmap with the same size as the background image
  Bitmap bmOverlay = Bitmap.createBitmap(mBitmap.getWidth(), mBitmap.getHeight(), 
      Bitmap.Config.ARGB_4444);
  // create a canvas on which to draw
  canvas = new Canvas(bmOverlay);
  
  Paint paint = new Paint();
  paint.setColor(Color.CYAN);
  paint.setTextSize(20);
  paint.setFlags(Paint.ANTI_ALIAS_FLAG);
  
  // if the background image is defined in main.xml, omit this line
  canvas.drawBitmap(mBitmap, 0, 0, null);
  // draw the text and the point
  canvas.drawPoint(fKoordX, fKoordY, paint);
  canvas.drawText("You are here", fKoordX+3, fKoordY+3, paint);
  
  // set the bitmap into the ImageView
  mIV.setImageBitmap(bmOverlay);
  </code></pre>