heatmap-pkg
v1.0.5
Published
A package for heatmaps on node.js and the browser
Downloads
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Readme
Heatmap
Heatmaps for node.js and the browser!
Example
blob.js
const Heatmap = require("heatmap");
const fs = require("fs");
const heat = new Heatmap(500, 500, { radius: 30 });
for (let i = 0; i < 5000; i += 1) {
let rho = Math.random() * 2 * Math.PI;
let z = Math.pow(Math.random(), 2) * 200;
let x = 250 + Math.cos(rho) * z;
let y = 250 + Math.sin(rho) * z;
heat.addPoint(x, y);
}
heat.draw();
fs.writeFileSync("blob.png", heat.canvas.toBuffer());
Methods
var heat = new Heatmap(...)
There are two ways of creating a new heatmap:
- With the id of the target canvas element
- With the height and width values for the canvas element to be created
Optionally, you can set the opts.radius
and opts.threshold
to control the
rendering a little.
heat.addPoint(x, y, params)
Add a point to the heatmap with a radius
.
params
must be an object and can have:
- radius, defaults to heat.radius || 20
- weight, defaults to 0.1
heat.scale(x, y)
Scale the canvas by the coefficients x
and y
.
If y
is undefined, scale both x and y by the first parameter, x
.
heat.draw()
Render all the points onto the canvas element.
heat.canvas
The HTML Canvas element.
Protip: with the canvas module for
node you can heat.canvas.buffer()
to get a Buffer with a PNG file all up in it.
Install
With npm, just do:
npm install heatmap-pkg
Or with yarn:
yarn add heatmap-pkg