Well not really a bug, but I didn't know where to post it and I want this to catch someone's attention badly, so Ashley :)
I did some experiments with mobile exports as you may know already and it came to me, that doing pixel rounding the way it's done in the runtime by Math.round(x) is the slowest way available to round a number.
Done some research and it seems that you can achieve double the speed by rounding using something called a Hack rounding with bitwise or:
rounded = (0.5 + somenum) | 0;
tested it by changing every instance of
if (this.runtime.pixel_rounding) ... Math.round
to the above code and i could actually see a little performance boost in more complex creations.
so... any chance this would be implemented in next c2 version pretty please? :)