node-geogebra

Run a geogebra script from nodejs and export your work to the desired format: pdf, svg, png and ggb.

Under the hood

It runs Geogebra Classic App through a headless chromium browser using the puppeteer package. This package provides an interface to programmatically utilize Geogebra classic app from nodejs.

Install

npm i --save node-geogebra

Build

npm i -g typescript
tsc

Classes

const GGB = require('node-geogebra');

GGBPool

constructor GGBPool(options?: GGBOptions)

Options parameters:
- ggb (default local): local or remote. Whether to load Geogebra classic app from the local copy or remotely from https://www.geogebra.org/classic
- plotters (default 3): number of plotters in the pool
Methods:
- async ready(): When resolved, the pool is ready to use
- async getGGBPlotter(): Picks a plotter from the pool
- async release(): Closes the pool. Please note that the nodejs process would not end unless you call this method.

// Pool options
const poolOpts = {
    plotters: 3,    //Number of plotters in the pool
    ggb: 'local'    //local or remote: From where to load Geogebra app
};
const pool = new GGB.GGBPool(poolOpts);
await pool.ready();
// From now on, you can start taking plotters from the pool

GGBPlotter

constructor GGBPlotter({ggb: "remote or local"})
constructor GGBPlotter(id?: number, page?: puppeteer.Page, releasedEmitter?: EventEmitter)

Optional parameters:
- id (default is randomly generated): string identifier
- page: If not passed then is generated
- releasedEmitter: Internally used by the GGBPool
Methods:
- async ready(): Promise. When resolved, the plotter is ready to use
- async reset(). Erases the plotter.
- async release(). Erases and returns the plotter to the pool
- async evalGGBScript(script: string[], width: number?, height?: number ). Sets the dimensions of the graph. script is an array that contains all the instructions required to generate your graph. The language used in these commands must be GGBScript. Internally, this method passes the GGBScript to the window.ggbApplet.evalCommand function.
- async exec(property, args: string[]): any. Executes the property on the window.ggbApplet object. For instance plotter.exec("reset") would do the same job as plotter.reset()
- async export(format: string): string or buffer. format can be: png, pdf, svg, ggb. It returns a buffer or a string depending on the format.
- async export64(format: string): string. format can be: png, pdf, svg, ggb. It returns a string containing a base64 representation of the buffer.
- async exportPNG(alpha: boolean, dpi: number): Buffer
- async exportPNG64(alpha: boolean, dpi: number): String
- async exportPDF(): Buffer
- async exportPDF64(): String
- async exportSVG(): Buffer
- async exportSVG64(): String
- async exportGGB(): Buffer
- async exportGGB64(): String

Example using a set of pooled plotters

   const plotter = await pool.getGGBPlotter();
   const ggbScript = [
       "A=(2,5)", "f=cos(x)", "t=Tangent(f,A)"
   ];
   await plotter.evalGGBScript(ggbScript, 600, 400);
   const svg64 = await plotter.export64("svg");
   console.log(svg64)
   await plotter.release();

Example without using GGBPool

   const GGBPlotter = require("node-geogebra").GGBPlotter;
   const plotter = new GGBPlotter({ggb: "local"});
   const ggbScript = [
       "A=(2,5)", "f=cos(x)", "t=Tangent(f,A)"
   ];
   await plotter.evalGGBScript(ggbScript);
   const svg64 = await plotter.export64("svg");
   console.log(svg64)
   await plotter.release();

Examples

We provide two examples: one using a single GGBPlotter and a second one with a GGBPool.

cd examples
node simple.js
node pooled.js