Anne van Kesteren

html:canvas in Opera 9

Opera got some comments on canvas support. Obviously a lot of people took that over and the general meme is now that it sucks. It is still experimental and in alpha state so that is not far away from the truth, although we can do cool things already. The main issue here is drawing. Where other browsers lock drawing during code execution Opera actually draws each new step incrementally. The code execution itself is very fast, just put var then = new Date(); before the loop and var now = new Date(); alert(now-then); after. You might want to use the improved demo as well which actually closes the drawing path after each iteration. (Makes the drawing a lot quicker too.) The difference here is that it uses beginPath() and closePath() to reset current drawing paths.

Anyway, not sure yet how this will be solved at Opera. It looks like this is a fundamentel difference between Opera and other browsers. Another way to solve the speed issue for authors is to draw on the canvas off screen before displaying it. Basically setting it to display:none and later to display:block. Arve showed me a demo which worked fairly well using that technique.