title: How to draw grid lines that scale?
body: <p>I have a canvas, and I want to give it grid lines as a background, but I want there to be a constant number of grid lines that divide the canvas into equally-sized sections, rather than just have equally-spaced grid-lines. I want this to be preserved when the canvas is resized by the user.</p>
  
  <p>How should I do this?</p>