README

cgil-geom2d

a light 2d geometry utility classes like Point, Line written in ES6 Javascript (~12k for the CommonJS lib).

this code is licensed under the terms of the MIT License.

Documentation generated from source with esdoc

Using it inside the browser

you can download the UMD library file dist/geom2d.min.js directy to your computer then you just need to include it as usual (adapting the path to your case):

<script src="dist/geom2d.min.js"></script>

you can see an example above

you can get a nice explanation for the various library formats in this medium article

but very basically

cjs (commonjs2): You will use this format in a build tool, it excludes all modules in node_modules folder from bundled files.
umd: You will use this format directly in browser, all 3rd-party packages (dependencies) will be bundled within.

Installation with npm

Inside an already created npm project directory (do you have a package.json in it ?) you can as usual install cgil-geom2d in the shell with :

npm install cgil-geom2d --save

then you can import/require the CommonJS bundle in dist/geom2d.cjs.js

Example

let's use the library Point class to create a nice 12 petal's flowers using a polar equation like this : r = a sin 6θ

Jump to the full example file

alt text

<script src="../dist/geom2d.min.js"></script>
<svg height="500" width="500">
  <line  id='xaxis' x1="250" y1="0" x2="250" y2="500" class="svgaxis" />
  <line  id='yaxis' x1="0" y1="250" x2="500" y2="250" class="svgaxis" />
  <polyline id='mypolargraph' points="0,40 40,40 40,80 80,80 " class="svg-flower-petal"/>
  <circle cx="250" cy="250" r="40" class="svg-flower-center" />
</svg>

  let ElPolyPolarGraph = document.getElementById('mypolargraph')
  let petalLength = 200
  let coordinatesString = '' // to accumulate the points coordinates
  // let's center the drawing on the svg
  const offsetX = 250 
  const offsetY = 250
  // let's iterate over a full 360 degree circle
  for (let angle = 0; angle < 360; angle += 2) {
        let radius = petalLength * Math.sin(6 * geom2d.utils.getRadians(angle)) // need to convert to radians for Math.sin        
        let TempPoint = geom2d.Point.fromPolar(radius, angle)
        // move the point so it's centered on the svg 
        TempPoint.moveRel(offsetX,offsetY)
        coordinatesString += TempPoint.toString(',', false)  + ' '
  }  
  // now update the points attributes in the existing svg polyline to display the flower on screen
  ElPolyPolarGraph.setAttribute('points', coordinatesString)

You can find other polar equations here

Develop

you can clone this repository with a git clone then run a npm install in the cloned directory
and use the various scripts inside package.json to help you work

Travis CI

create the CommonJS bundle in dist folder

npm run build:CJS

create the UMD bundle in dist folder

npm run build:UMD

run unit tests with jest

npx jest -i --watch

or just

npm run test

run eslint with

npm run lint

Usage no npm install needed!