title: In WPF what is the proper method for drawing a line and PNGs on a bitmap that is attached to a canvas?
body: <p>I don't do that much with WPF anymore and I always seem at a loss for the most basic things. I've tried the Googles but they're not helping.</p>
  
  <p>I've got a canvas (maybe I shouldn't use a canvas?) and I want to attach an image. The only way that I could find to do this was like so:</p>
  
  <pre><code>&lt;Canvas Grid.Column="2" HorizontalAlignment="Right" Height="822"  VerticalAlignment="Top" Width="1198" Name="MainCanvas"&gt;
      &lt;Canvas.Background&gt;
          &lt;ImageBrush ImageSource="/MapDesignModule;component/MapFrame.bmp" Stretch="None" AlignmentY="Top" AlignmentX="Right"/&gt;
      &lt;/Canvas.Background&gt;
  &lt;/Canvas&gt;
  </code></pre>
  
  <p>Now, I need to draw lines on the image attached to the canvas (later I will also have to place transparent PNGs, or BMPs with white set to Alpha 0, on the image as well). </p>
  
  <p>In the past I would get a writeablebitmap from the image.source but you apparently can't do that from an ImageBrush? </p>
  
  <p>What is the 'proper way' to put an image on the screen and draw and blit images onto it?</p>