Reference class container in Javascript
<p>I have a Pic class with methods such as this.pic_w, this.pic_h.
Inside one of the methods of the class, im initializing an Image object and rewriting one of it's methods.
How can I access my Pic variables (this.pic_w, this.pic_h) from the Image redefined method that is inside one of Pic's methods but does not inherit from Pic?
Here are the class variables:   </p>

<pre><code>Pic.prototype = new DaVinci();
Pic.prototype.constructor = Pic;
function Pic(canvas) {
    this.canvas = canvas;
    this.pic = "";
    this.resize_w = 200;
    this.resize_h = 200;
    this.pic_w;
    this.pic_h;
}
</code></pre>

<blockquote>
  <p>...Some other methods...</p>
</blockquote>

<pre><code>Pic.prototype.draw = function( img_src, pos_x, pos_y ) {
    this.setPos(pos_x,pos_y);
    this.setPic(img_src);
    var ctx = this.setWidget();
    var x = this.pos_x;
    var y = this.pos_y;
    var img = new Image();
    img.src = this.pic;
    img.onload = function() {
        // How can I access Pic class methods and variables from here?
            ctx.drawImage(img, x, y, this.width, this.height);
    }
}
</code></pre>
