====== Paper.js ======
  * Official Site:[[http://paperjs.org/|paperjs.org]]
  * Features:
      * Paper.js provides a Document Object Model (also called a Scene Graph) that is very easy to work with. 
      * Paper.js makes is very easy to create and paths and add segments to them,and easy to manipulated segments.
      * Paper.js Supports mouse interaction and keyboard interaction.
      * SVG Import and Export, Raster Images, Color Averaging, Symbols, Selection Outlines, Vector Geometry, Mathematical Operations
      * Flexibility in parameter conversion when passing values to functions