[whatwg] getImageData/putImageData comments
bzbarsky at MIT.EDU
Fri Jul 10 16:34:06 PDT 2009
Ian Hickson wrote:
>> For another example, consider an algorithm that wants to reduce the size of
>> the image by 1px horizontally (e.g. content-aware image resizing as demoed
>> using canvas at
>> If we're shrinking by one device pixel, then suddenly we can't even create a
>> canvas of the right size for the new image, because canvas size is specified
>> in integer CSS pixels. Note that the algorithm used here, basically
>> off-the-shelf, would in fact want to work on device pixels the way the spec is
>> written right now; in general it would want to work on whatever pixels
>> imagedata is in.
> If you want to shrink an image, redraw it using drawImage() with different
You apparently didn't look at the linked-to page. It's basically
applying a graphical filter to an image that results in a smaller image.
It's explicitly NOT trying to resize the image using whatever
algorithm the browser happens to implement; it's implementing its own
image-resizing algorithm (one that arguably produces much better results
at the cost of a lot more computation).
> I don't know what we can do about it either, though.
I'll think about this some more... I'm not too hopeful, though. :(
Especially for that image-resizing case, where we basically need to be
able to create a canvas with fractional CSS pixel dimensions or something.
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