Why is the image drawn in the canvas when debugging but not when running?

Question

I\'m learning HTML5 and Javascript and I\'m trying to draw an image on a canvas. I have the following code which draws the image if I step through the code after breaking on the

Answer 1

You have to wait until the image element is fully loaded by the browser before calling the drawImage method, even if your image element is created from a base64 string and not from an external file. So just make use of the onload event of the image object. A quick fix would be like this:

var img = document.createElement('img');

img.onload = function()
{
    var canvas = document.getElementById('picCanvas');
    canvas.width = this.width;
    canvas.height = this.height;
    var ctx = canvas.getContext('2d');
    ctx.drawImage(this, 0, 0);
}

img.src = e.target.result;