I made something similar for a webapp of mine (demo at http://www.wysp.ws/practice/course/1057894/ http://www.wysp.ws/practice/course/1057894/ -- it's meant for

I made something similar for a webapp of mine (demo at http://www.wysp.ws/practice/course/1057894/ http://www.wysp.ws/practice/course/1057894/ -- it's meant for painting so the functionality is a bit different, you control opacity) A difficulty I had was to make the lines smooth whereas the cursor positions are not sampled very fast by the browser. I'm curious as to what your approach was, since everything seems perfectly smooth. I'll be reading your code...