node-geogebra/examples/pooled.js

Generate graphics with geogebra from nodejs

const GGBPool = require("../dist/GGBPool").GGBPool;
const fs = require("fs");

// You can test the startup time by changing ggb to local or remote
// Please note that "remote" option is not working at the moment :-(
const pool = new GGBPool({ggb: "local", plotters: 3});

(async () => {
    const t0 = new Date();
    // It is required in the pool to wait its creation
    await pool.ready();
    const t1 = new Date();
    
    console.log("> Startup time", t1.getTime()-t0.getTime());
  
    const t2 = new Date();
    async function doFunGraph(task, axisScales, dimensions, ext) { 
        // Every plotting task takes a plotter from the pool
        const plotter = await pool.getGGBPlotter();
        console.log(task + ":: has taken from the pool, plotter id=" + plotter.id);
        // This is the desired image size in pixels
        const w = dimensions[0];
        const h = dimensions[1];  
        
        const xA = Math.random()*Math.PI;
        const ggbScript = [
            "f="+task+"(x)", 
            "A=("+xA+",f("+xA+"))",             
            "t=Tangent(f, A)",
            "SetColor(f, blue)",            
            "SetLineStyle(t, 1)",
            "ZoomIn("+ axisScales.join(",")+")"];

        await plotter.evalGGBScript(ggbScript, w, h);
        console.log(task + ":: has been evaluated in plotter id=" + plotter.id);
        const fileContents = await plotter.export(ext);
        console.log(task + ":: pdf has been exported in plotter id= " + plotter.id);
        fs.writeFileSync("pooled-ggb-" + task + "." + ext, fileContents); 
        
        // Very important is to release the plotter to the pool. The reset method is not sufficient!
        await plotter.release();
        console.log(task + ":: plotter "+ plotter.id + " has been erased & returned to the pool.");
    }
  
    /*
     * In this example we are using a a pool of plotters, so calls
     * can be run in parallel. 
     * If you need a series plotting look at simple.js example
     */
    await Promise.all([
        doFunGraph("sin", [-6,-2,6,2], [300,200], "pdf"),
        doFunGraph("cos", [-10,-1,10,1], [400,300], "png"),
        doFunGraph("tan", [-3,-4,3,4], [800, 600], "svg"),
        doFunGraph("arctan", [-10,-3,10,3], [500, 500], "ggb")
    ]);
    const t3 = new Date();
  
    console.log("Plotting Time ", t3.getTime()-t2.getTime(), " ms")
  
    /*
     * Node process would not finish unless you release the GGBPool 
     */
    await pool.release();
    console.log("GGBPool instance has been released.");
  })()