On May 13, 2008, at 1:53 PM, Vladimir Vukicevic wrote:
The first argument to the method must be an ImageData object returned by createImageData(), getImageData(), or an object constructed with the necessary properties by the user. If the object was constructed by the user, its width and height dimensions are specified in device pixels (which may not map directly to CSS pixels). If null or any other object is given that does not present the ImageData interface, then the putImageData() method must raise a TYPE_MISMATCH_ERR exception.
If we were to add that we should include a note to indicate that using a custom object is not recommended -- Any code that uses a custom created object will never benefit from improvements in ImageData performance made by the UA. That said I still don't believe custom objects should be allowed, aside from the resolution (which may or may not be relevant) and performance issues, a custom object with a generic JS array, rather than an ImageData object will have different behaviour -- a proper ImageData will clamp on assignment, and throw in cases that a custom object won't.
- Vlad
--Oliver
