[whatwg] drawImage with non-existent images
ian at hixie.ch
Thu Jun 12 15:24:09 PDT 2008
On Sun, 17 Feb 2008, Jeff Walden wrote:
> > If the image argument is an HTMLImageElement object whose complete
> > attribute is false, then the implementation must raise an
> > INVALID_STATE_ERR exception.
> This is all well and good in the case where the image being drawn has
> the same origin as the document where the canvas resides, but if the two
> have different origins, this makes it possible to determine the
> existence of an image on a foreign server. This exception must only be
> thrown if the image element's origin is the same as that of the document
> containing the canvas being modified.
> (You can already determine image existence by seeing how an image
> affects page layout, but this still seems like a reasonable behavior
There's all kinds of ways to determine if a remote resource is present or
not -- onload/onerror on <img> or <iframe>, importing a script from that
host, layout effects of an image, layout effects of a style sheet...
I think that ship has sailed.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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