Nice design, the brush shapes are pretty. But honestly, this is the kind of application which used to be provided as a demonstration of Turbo Pascal's graphics library in 1990... Multiplying some lines into a greyscale buffer on mouse events was perfectly feasible on a 286 + VGA. Meanwhile in 2010, Flash Player 10 can render 300K 3D particles in software: http://www.unitzeroone.com/labs/alchemyPushingPixels
this is the kind of argument which was used to demonstrate how inadequate pcs where compares to mainframes in the 80's. Apologies for any snarkiness :) but we are going to hear about how much canvas sucks compares to opengl whatever until it surpasses it, and probably still then.
So you mean '80s mainframes were actually PCs, but they had a faster virtual machine, better language support and a more expansive standard library? Because, you know, both the Canvas demo and the Flash demo run on the same hardware...
Don't get me wrong, I really like Canvas. But it's harmful to pretend that it's a Flash replacement, when Flash still does a lot more and also has authoring tools that allow actual content to be produced by design professionals.