On Wed, 09 Dec 2009 12:08:29 -0500, Ian Hickson <[email protected]> wrote:
On Fri, 30 Oct 2009, OmegaJunior wrote:
Since Last Call was announced and I just ran into this problem, hereby
this question:
If an image is drawn on a Canvas element, and subsequently the
javascript function cloneNode(true) is executed for that element, should
the clone include a copy of the source canvas image, or should it show
an empty space?
From my perspective (the web author), I'd prefer to have the canvas
image included when executing (the deep) cloneNode(true), and excluded
it when using (the shallow) cloneNode(false).
The cloneNode() method just clones the node, not the node's state, so the
bitmap isn't copied. You can easily draw one bitmap onto the other,
though, using drawImage().
On Sat, 14 Nov 2009, Michael A. Puls II wrote:
I think it'd be cool if the clone showed the image. But, I'm pretty sure
cloneNode(true) is just supposed to create a new canvas element with the
same attributes and childNodes as the original. It's not supposed to
copy everything that's going on with the element being copied.
There are some exceptions with state for certain elements. Perhaps that
can happen with canvas too.
I'd rather keep these exceptions to an absolute minimum. cloneNode() is
part of the DOM Core API, and it would be bad for nodes to clone
differently based on whether it's an HTML-aware UA implementing the DOM
Core API or not.
Thanks.
I don't know canvas stuff that well. What's the proper way to patch
cloneNode to do a full copy?
I think something like the following, but maybe you know better.
(function() {
var oldCloneNode = HTMLCanvasElement.prototype.cloneNode;
HTMLCanvasElement.prototype.cloneNode = function(deep) {
var copy = oldCloneNode.call(this, deep);
var copy_ctx = copy.getContext("2d");
copy_ctx.drawImage(this, 0, 0, this.width, this.height);
return copy;
};
})();
--
Michael
