Ranked in these QuestionsQuestion Ranking
Pro Operator overloading
Pro Geometric Tests
An almost-unique feature: can test geometry if contains(), isInside() or intersects() one other object. Offers even hit-testing methods!
Pro Behaviours handled by objects
These features make it easier to create objects that can act autonomously with complex behaviors. This makes Paper a good choice for particle effects and game development.
Pro Object constructors
Elements all have the option of being created with a hash of properties which promotes clean, concise, and contextually local coding practice.
Pro Good for making games
Paper uses a frame based approach to rendering the canvas. This makes it conceptually easier to create objects with animations and behaviors that interact and perform with other objects.
Along with Paper's approach to creating and managing objects this makes Paper especially good for creating applications with complex behaviors with many elements doing different actions at once, and makes it a good choice for making games.
Pro Very simple
It's one of the easiest drawing libraries to learn.
Pro Works with all of the common browsers
That includes: Chrome, Safari, Opera, Firefox and IE 10+
Pro Pretty lightweight
Con Limited to single instance
The code is written in a way that everything is global and limited to a single instance, there is no clean way to use 2 separate instances in the same page
Con Not supported in older browsers
Paper.js runs on top of HTML5 Canvas, which is not supported in older browsers.