title: Drawing with mouse causes gaps between pixels
body: <p>I have been creating a drawing app as a test for WPF, and have been going well. The problem I've run into is that if I draw the pixel under the mouse to a bitmap each time it moves, I only get one pixel per update. When the mouse moves around fast it doesn't draw the pixels  in between. I need to know what the best way to draw a line between to pixels is in WPF using <code>WriteableBitmap</code></p>
  
  <p>EDIT: Now I have this:</p>
  
  <p><img src="https://i.stack.imgur.com/Vf3jz.png" alt="LinesNotConnected"></p>