[whatwg] "canvas" reading ???

Charles Iliya Krempeaux supercanadian at gmail.com
Mon Jun 13 18:30:11 PDT 2005


I know people are going to want to read individual or groups of pixel
values.  Certain image processing algorithms require it.  (For
example, certain edge detection algorithms.  Etc.  There's alot of
different ones.)

Now, I'm aware of the toDataURL() method.  (Which is a very nice
feature!)  However, I don't think it is enough for image manipulation
and processing.  (Or at least not convenient.)

Mainly, the reason is that the "data" that toDataURL() will return is
encoded in PNG format.  It is not a raw-uncompressed image.  (Which
doesn't make it amenable to image manipulation and processing.)

So,... if there isn't a way of reading pixel values, you'll find that
people are writing their own PNG decoders in JavaScript.  (Which
really isn't ideal.)

See ya

     Charles Iliya Krempeaux, B.Sc.

     charles @ reptile.ca
     supercanadian @ gmail.com

     developer weblog: http://ChangeLog.ca/
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