Entropretty

A simple Javascript-based entropy-to-graphic harness.

Try it at https://gavofyork.github.io/entropretty/.

Usage

Just view the index.html file in a browser locally.

Playing around

1. Create a new .js file with a unique name, for example foo.js.
2. Implement a draw function (see below) and call it something like drawFoo.
3. Put a call to addSchema("Foo", drawFoo) at the bottom. See below for the additional arguments.
4. Introduce a new line right before </body> in index.html:

<script type="text/javascript" src="foo.js"></script>

The addSchema function

The addSchema function accepts up to 4 arguments (the last two are optional):

• name: The name of your schema.
• draw: The function to draw a figure, see below.
• nibbles: The number of nibbles of entropy your schema can place into a figure. It is best to make this at least 4 but preferably the maximum and default which is 8.
• mutate: A function for mutating a seed. This defaults to the flip of three random bits.

Seeds

A seed represents the entropy of a figure and is just an array of nibbles (numbers between 0 and 15 inclusive). There are several functions provided for operating on them:

• bit(seed, n): Get the nth bit from the seed, indexed from 0. Returns either 0 or 1.
• bits(seed, from, to): Get a number built from the bits of seed of the given span from and to.
• split(seed, parts): Return an array of numbers, parts in length, each using approximately the same number of bits from the seed.

The Draw Function

Draw functions take three arguments:

• ctx: The Javascript canvas 2D drawing context.
• size: The size (width and height) which the figure should be drawn in.
• seed: The seed entropy from which the figure should be drawn.