title: How to draw on Windows Phone like on HTML canvas
body: <p>I want to draw on Windows Phone 7 (Xna or whatever) like I draw on a HTML canvas, Processing or Java Graphics. Is it possible?</p>
  
  <p>I found an answer that say to use the WriteableBitmap class, but how can I use it?</p>
  
  <p>What I want is to draw in a raster image with functions like fillRect, fillOval, drawImage, etc...</p>