If you are changing any context settings and need to reset them for each new frame,
you need to use the save() and restore() methods.
Chapter 6: Advanced Programming Topics: Canvas and Video
145
The following HTML page shows a simple animation program in which a circle moves diagonally
from the top left to the bottom right part of the canvas:
???http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd???>
Animateuser-scalable=0;???>