title: Bitmap scaling to fit different screen size/density
body: <p>I do not really understand all those things about pixel density and device independant pixels and I want to know if I should worry about this.</p>
  
  <p>More specifically, here is how my application work right now:</p>
  
  <ul>
  <li>For the “layout screens”, I’m using RelativeLayout or LinearLayout and I never use pixels or dp, so I guess that this will look good on every device</li>
  <li>For the main game screen, there is only a SurfaceView on the screen. With the values given by <code>onSurfaceCreated()</code> (pixels or dp? I don’t know), I compute the size and position of every element of the game, then I load the Bitmaps (with <code>BitmapFactory.decodeResource()</code> and then <code>Bitmap.createScaledBitmap()</code>) and put them on the screen with <code>drawBitmap()</code></li>
  </ul>
  
  <p>I tested on my phone (480 × 800 hdpi) and on the emulator (240 × 320 mdpi), and both looks good.</p>
  
  <p>My questions are:</p>
  
  <ul>
  <li>Is this the right thing to do? I do not understand how (and why) I could use the fact that some devices are hdpi and others are mdpi.</li>
  <li>Should I provide different bitmaps for different screen densities, and why? (right now I have everything in <code>res/drawable-hdpi</code>)</li>
  <li>What size should my .png have? Can I create them much bigger (2 ×) than their expected size, in order to be sure that this will not look blur or aliased?</li>
  </ul>