OCDots

OCDots is a javascript library for creating evenly distributed points inside a polygon

Check the demo!

Quick Start

OCDots uses physics to maximize the distance between each point and also the distance to the walls of a polygon. It is possible to follow each step of the process calling movePoints, or call relaxPoints to run several iterations and see the final state.

Import the library, then call movePoints on a set of points to run one iteration

const polygon = [
  [0, 0],
  [0, 500],
  [500, 500],
  [500, 0],
  [0, 0],
];
const points = [
  [10, 10],
  [20, 20],
  [30, 30],
  [40, 40],
  [50, 50],
  [60, 60],
  [70, 70],
  [80, 80],
  [90, 91],
];
let momentum = points.map(() => [0, 0]);
const newPoints = movePoints({
  points,
  momentum,
  polygon,
}); // Points closer to the relaxed position
// newPoints:
// [[13.535794548720887, 13.535273243928348],
// [23.27147728369301, 23.266677836465515],
// [31.254830565917008, 31.24699231498995],
// [41.28615235332842, 41.272681142242014],
// [51.958871850605114, 51.93302052874113],
// [63.120940102952105, 63.061513386276076],
// [73.60106973613009, 73.4687601178992],
// [83.7612857566466, 83.29434810802492],
// [93.40654447613721, 94.65998015460454]]

Or call relaxPoints to run several iterations:

const polygon = [
  [0, 0],
  [0, 500],
  [500, 500],
  [500, 0],
  [0, 0],
];
const points = [
  [10, 10],
  [20, 20],
  [30, 30],
  [40, 40],
  [50, 50],
  [60, 60],
  [70, 70],
];
const iterations = 600;
const newPoints = relaxPoints({
  points,
  polygon,
  iterations,
}); // Points closer to the relaxed position, 600 iterations
// newPoints:
// [[102.97786539754973, 102.93913654344668],
// [249.88751973067804, 95.97842402445758],
// [95.85157380539883, 249.581118685883],
// [249.83589254388568, 250.64858636270534],
// [103.38882973892018, 396.3498058144843],
// [396.8795797129724, 103.0543405820668],
// [249.77618266302204, 404.4383179086723],
// [404.0862954198404, 249.7401659115181],
// [396.995879400969, 396.84327821075937]]

Install

Install with npm:

npm install ocdots

To use with node just import the module:

const ocdots = require("ocdots");
ocdots.movePoints(...);

In the browser import the script and then

<script src="node_modules/ocdots/docs/ocdots.js"></script>
<script>
  ocdots.movePoints(...);
</script>

You can also download the file and import as you prefer. No extra dependencies are required.

Usage

ocdots provides several functions to iterate a set of points in a polygon. All functions must be called with named parameters

Arguments description

• points {Array} The points to move. An array of 2D coordinates. Eg: [[0, 0], [0, 1], ...].
• polygon {Array} The polygon vertexes. An array of 2D coordinates. Eg: [[0, 0], [0, 1], ...]. This polygon should be ordered (clockwise or anticlockwise) and closed i.e. first points equals the last point.
• momentum {Array} Accumulated momentum for each point. An array of 2D coordinates. Eg: [[0, 0], [0, 1], ...].
• baseForce {Number} The force between points and also the walls.
• drag {Number} The drag coeficient

ocdots.movePoints

Moves points according to the applied forces into it. The forces are: 1) between points, 2) between the point and walls of the polygon, 3) between points and vertexes of the polygon.

The points moves according to it's momentum up to maxMomentum. Drag reduces the momentum with the square of the momentum. Viscosity lowers the momentum of points with high forces.

Runs one iteration

Parameters

• points
• momentum
• polygon
• baseForce
• drag @param {Number} viscosity The viscosity coeficient @param {Number} maxMomentum Maximum momentum for each point @param {Boolean} parallelForces Sum line segmen parallel forces as well. @return {Array, Array} points,momentum Updated points and momentum arrays

A running example can be found here.

License

OCDots Copyright (C) 2020 Luiz Eduardo Amaral luizamaral306@gmail.com

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License