Create interface for image encoding

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Right now, JPGEncoder and PNGEncoder do essentially the same thing, but provide 
different API 
naming schemes to do it.

For example, JPGEncoder uses a instance encode API, where as PNGEncoder, uses a 
static encode 
APIs.

We should standardize the APIs, perhaps creating a formal interface for them.

Might be worth looking at the Flex based encoding classes to figure out the 
interface that should be 
used (although these classes should not require Flex).

Original issue reported on code.google.com by mikechambers on 21 Sep 2009 at 5:21

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Original comment by mikechambers on 22 Sep 2009 at 7:49

[GoogleCodeExporter]

Note, one thing to consider when thinking about whether we have a static encode 
method, or require the use the 
create an instance of the encoding class, is whether we plan to eventually 
support an asynchronous encode 
method / api.

RIght now, I think this would be useful as encoding can be pretty CPU 
intensive, although some of the 
performance improvements we are considering might not make this as important.

Anyways, we should consider this when designing the interface / api.

Original comment by mikechambers on 22 Sep 2009 at 8:13