title: HTML 5 canvas image special effects
body: <p>I'm working on a 2d tile based HTML5 canvas application and I would like to know what kind of special effects I can apply to the images as their being drawn ( context.drawImage(...) ). The only trick I've come across is modifying the canvas.globalAlpha value. This leaves some color from the previous frames, creating a blurring or dazed effect if things on the canvas object are moving from frame to frame.</p>
  
  <p>Is there something for rendering images that is comparable to setting the context.fillStyle to an ARGB value for primitive shapes?</p>
  
  <p>Is there a multiply mode? ie: multiply the image pixel color by the destination color. This could be used for primitive lighting. (I've toyed around with context.globalCompositionOperation but didn't find anything interesting)</p>
  
  <p>Are there any other cool effects you've come across?</p>
  
  <p>NOTE: I don't want to use WebGL for this application, and it's a game. That means it's realtime and I can't modify each pixel with javascript code because that takes too long. (although I could probably do that when the player dies and nothing is moving on the screen anymore)</p>