HTML5 Canvas & Same-Origin

[zeveck]

I am loading the page into QWebView like so,

@QWebView::setHtml(content, QUrl("file://"));@

The content includes something like,

@<img src="file:///F:\foo.png">@

I then try to do this in JS:

@var canvas = document.querySelector("canvas");
var cxt = canvas.getContext("2d");
var image = document.querySelector("image");
cxt.drawImage(image, 0, 0);
var imgData = cxt.getImageData(1, 1, 1, 1);@

This doesn't work, apparently due to a SameOrigin error because if I just add,

@settings()->setAttribute(QWebSettings::LocalContentCanAccessRemoteUrls, true);@

then it works fine, except I don't want to do this since it's a general security concern...

But since the page is loaded with base "file://" and the file is being loaded from "file://" ... how is this a SameOrigin conflict!?

Can anybody explain what I'm missing?

(I'm using Qt 4.8.4.)