title: Canvas jagged line issue
body: <p>I've built a very simple line graph using canvas (pulling in data from google analytics). I'm having a few small issues. First off, the plot line is jagged:</p>
  
  <p><a href="http://jsfiddle.net/uJQ7K/" rel="nofollow">http://jsfiddle.net/uJQ7K/</a></p>
  
  <p>I'm just using lineTo for this:</p>
  
  <pre><code>ctx.lineTo((i*cellWidth) + cellWidth + padding,(tableHeight + padding) - data[i].v);
  </code></pre>
  
  <p>I've read that using splines can fix this but surely there's a way to draw a straight line out of the box?</p>
  
  <p>Other problems I'm having are changing one attribute like strokeStyle changes all the strokes on a page. How do I just change the stroke of the plot line and not affect the appearance of the grid?</p>