@rgsoft/turtle v1.0.0

Turtle

Turtle and L-Systems library

L-Systems

The LSystem class is an implementation of the Lindenmayer systems based on an alphabet of symbols and production rules.

const lsystem = new LSystem(axiom, rules);

The axiom is the base sentence from which future sentences will be generated or inferred, and must be composed only by symbols of a defined alphabet. This alphabet is based on the Turtle Graphics movements.

F, G, L, M, D, U, +, -, [, ]

The rules is an array of strings or instances of the Rule class, where each one of them defines a production rule for spawning the next generation sentence.

Generation

The generate method in the LSystem class spawns new generations of the current sentence.

const axiom = 'F';
const rules = [
    'F=>F[+F][-G]'
];
const lsystem = new LSystem(axiom, rules);
console.log(lsystem.sentence); // F
lsystem.generate();
console.log(lsystem.sentence); // F[+F][-G]

This method also admits a number argument that indicates the number of generations to generate.

const axiom = 'F';
const rules = [
    'F=>FG'
];
const lsystem = new LSystem(axiom, rules);
console.log(lsystem.sentence); // F
lsystem.generate(4);
console.log(lsystem.sentence); // FGGGG

Rules

The Rule class represents a production rule that allows the generation from a symbol to a string of one or more symbols from the alphabet.

const str = 'F => F[+F][-F]';
const rules = [ new Rule(str) ];
console.log(rule.base); // F
console.log(rule.next); // ['F', '[', '+', 'F', ']', '[', '-', 'F', ']']

The LSystem class uses this class to maintain and generate the sentences.

Turtle Graphics

The Turtle class is a clumsy attempt to use a "sentence" driven drawing engine based on the turtle graphics. The sentences use the same symbols in the LSystem and Rule alphabet, with each symbol having a specific usage.

The render method reads each symbol in the string, and performs an action according to the previous table.

const turtle = new Turtle(config);
turtle.render(sentence);

Turtle Config

The config argument for the Turtle class constructor has these properties:

The ScaleConfig has this properties: