When comparing Processing.js vs Raphael, the Slant community recommends Processing.js for most people. In the question“What are the best JavaScript drawing libraries?” Processing.js is ranked 4th while Raphael is ranked 5th.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Good at creating complex visual effects and filters
Pro Fast rendering of complex scenes
Because Processing doesn't keep track of shape objects it's more efficient than other libraries. Processing can do more complicated effects faster than other libraries. Although this means you have to keep track of more yourself in your code, it also means you have more control over the finer details of how things are rendered.
Pro Cross-platform compatibility
In processing you can write code in both JavaScript and Processing code. This allows you to use existing Processing code on the client side.
Processing code is similar to Java in that it has static typing. This can make more complex calculations more robust, and less likely to cause conflicts.
The library takes a more frame based approach to rendering, so you use drawing functions to draw directly to the frame without objects. This can make it easier to write efficient full frame rendering scenes and post processing effects.
Pro Works with older browsers
Because Raphael supports rendering VML + SVG, it is one of the few drawing libraries that is backwards compatible with older browsers that do not support canvas.
Pro Built in animations
Several built-in animations (such as ways of easing) are provided for you out of the box, but Raphael also allows cubic beziers for more complicated easing functions. Any drawing object property can be modified making it similar to css animations in jQuery.
Pro Every object is interactive with events
Everything that is drawn in Raphael is an object which means it is easy to manipulate any part of the rendered image after it is processed. It uses an event handler system for user inputs which makes it easy to learn for JavaScript developers used to event based libraries.
This style of handling objects makes Raphael a good fit for rendering interactive diagrams and charts that can also interact with other parts of the page.
Pro Easy creation of charts with extension
gRaphael is a Raphael extension to help you easily create graphs and charts.
Cons
Con Processing.js is now archived, and won't be updated
Con Complicated, confusing documentation
The documentation is often not clear and lacks practical examples.
Con Can be difficult to get support
Online communities for Raphael are small and inactive compared to other drawing libraries, and many issues opened on github are never addressed.