The author already mentioned that he uses ExCanvas for IE. I don't think it's a stretch to use a library for what would otherwise be tedious recoding of the sam

The author already mentioned that he uses ExCanvas for IE. I don't think it's a stretch to use a library for what would otherwise be tedious recoding of the same logic in both SVG and VML. If a library helps you deliver the software faster and better, use it. If it gets in your way, then consider using the layer underneath directly. But, regardless, my main point was to consider browser-based _vector_ graphics, which are several orders of magnitude faster than canvas for activities like this.