how to save canvas data to file

Question

i am using node.js to save canvas to image img in writeFile is extractedby using toDataURL on my canvas element. it doenot save file here is my code

var fs          


        

Answer 1

Here is a literal example of how to save canvas data to a file in Nodejs. The variable img is a string generated by canvas.toDataURL(). I've assumed you already know how to POST that string from the browser to your Nodejs server.

HTML snippet that generates the sample image I used:

Nodejs snippet to decode the base64 data and save the image:

fs = require('fs');
sys = require('sys');
// string generated by canvas.toDataURL()
var img = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABQAAAAUCAYAAACNiR0"
    + "NAAAAKElEQVQ4jWNgYGD4Twzu6FhFFGYYNXDUwGFpIAk2E4dHDRw1cDgaCAASFOffhEIO"
    + "3gAAAABJRU5ErkJggg==";
// strip off the data: url prefix to get just the base64-encoded bytes
var data = img.replace(/^data:image\/\w+;base64,/, "");
var buf = new Buffer(data, 'base64');
fs.writeFile('image.png', buf);

Output: