Canvas

Provides a more Clojurescriptish access to the Canvas API while remaining true to it.

While looking low-level to web developers, the Canvas API is somewhat high-level in the world of graphics. Further abstractions tend to mask performance issues and the full range of possibilities it offers. As such, this library is almost a one-to-one mapping with a fluid interface, improved names, and barely a few additional utilities. The purpose is to make the API more enjoyable from Clojurescript without any black magic involved.

A second reason not to provide anything more exciting or extravagant is that when it comes to graphics, higher-level abstractions are usually built according to the specific requirement of the application. A data visualization software radically differs from a game, yet both might use a canvas. This field is one where there is no "one size fits all". Or, as they say: "one person's abstraction is another person's garbage".

Usage

Prior knowledge of the Canvas API is preferred. However, the documentation clearly helps in acquainting oneself with it as pretty much all docstrings have links to the relevant functions and properties described by the Canvas API in MDN

Other than that, dare to be bold.

Why not Quil?

The Quil project is a well-known graphics library in the Clojure community. It is perfectly adequate for at least some use cases as it provides higher-level utilities than just drawing to a canvas. It is crossplatorm and has basic support for WebGL, for instance.

However, if the intent is to clearly draw on a canvas, then it obfuscates lower-level operations and can become cumbersome for more serious projects. In those cases, we recommend sticking to direct access to the canvas without any additional layer as we believe it will be more fruitful, at least in the longer term.

Animation

Graphics libraries typically offer utilities for drawing but not for animating (how values needed for drawing evolve over time). As it turns out, animation is actually a very specific topic and it is particularly hard to produce a general-purpose library. Librairies specifically aimed for animation, in any language, tend to be opiniated and often counterproductive for more serious projects.

The exciting world of simulation happens to be an excellent way to understand animation. We recommend the DSim library which was clearly built for such endaveours. Familiarizing oneself with it takes some learning curve as it invokes concept from simulation, possibly new to the user ones, but acquiring those concepts result in great flexibility and versatility.

Tutorials showing how to combine both might be available in the future. However, the user shall be as compliant as to not hold his/her breath.

License

Copyright © 2020 Adam Helinski

Licensed under the term of the Mozilla Public License 2.0, see LICENSE.