Re: [whatwg] drawImage with non-existent images
On Sun, 17 Feb 2008, Jeff Walden wrote: http://www.whatwg.org/specs/web-apps/current-work/multipage/section-the-canvas.html#drawimage: 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 anyway.) 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. `._.-(,_..'--(,_..'`-.;.'
Re: [whatwg] drawImage with non-existent images
On Mon, 18 Feb 2008 03:24:45 +0100, Jeff Walden [EMAIL PROTECTED] 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 is already possible using the error and load events and the complete attribute on img. There's no new risk here. -- Anne van Kesteren http://annevankesteren.nl/ http://www.opera.com/
[whatwg] drawImage with non-existent images
http://www.whatwg.org/specs/web-apps/current-work/multipage/section-the-canvas.html#drawimage: 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 anyway.) Jeff
