getImageData not working for loaded image

[badjano]

var Canvas = require('canvas')
var Image = Canvas.Image;
var fs = require('fs');

fs.readFile(__dirname + '/img/image.png', function(err, data){
if (err) throw err;
var img = new Image();
img.onload = function(){
var canvas = new Canvas(img.width, img.height);
var ctx = canvas.getContext('2d');
ctx.drawImage(img, 0, 0, img.width, img.height);
var imageData = ctx.getImageData();
}
img.src = data;
});

// LOG BELOW

var imageData = ctx.getImageData();
^

Error: IndexSizeError: The source width is 0.
at Error (native)
at img.onload (/MyProject/test.js:12:25)
at Image.src (/MyProject/node_modules/canvas/lib/image.js:30:17)
at /MyProject/index.js:40:11
at FSReqWrap.readFileAfterClose as oncomplete

[zbjornson]

getImageData takes four parameters: https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/getImageData. You probably want getImageData(0, 0, img.width, img.height).

[badjano]

I'm sorry, thank you!