jQuery "Circle Shape" Animation

http://www.beautifulexplorer.com/main.html?skip=1

When you first open this website there is pie-chart that is center-wipe-animated or sth like that. I looked up the code and it seems like its jQuery but I just wan开发者_StackOverflow社区ted to know if there is a more isolated example of this type of mask(?) animation?

That particular example is done via the <canvas> tag of HTML5.

Here's some examples of animations and effects.

If have more questions, comment and I'll try and help.