Thumbnails API question

[Hubert Figuiere]

Hi,

I have an API question. It is not about the use but its design as I have to 
make choices, and I'd rather make the right one.

Extracting the thumbnails is done today by asking for a size. There are 
currently 3 sizes:
		OR_THUMB_SIZE_SMALL,
		OR_THUMB_SIZE_LARGE,
		OR_THUMB_SIZE_PREVIEW

SMALL is the smallest, basically 160x120 that Exif has. But not all files have 
it, like DNG.
LARGE is the larger one, vary from vendor to vendor, and may not be available. 
Typically 640x480, but not necessarily.
PREVIEW is typically the JPEG version of the raw file as some format like PEF 
seems to have, or CRW. The problem how to define such preview?

I plan to provide an API to query these types, and an API to convert them to 
the format you want, ie PNG or JPG, and list all what is available.

But the question is:
should I just change the API to extract the thumbnail giving a base dimension 
(like 320) and let libopenraw decide which one is the best (like the smallest 
thumbnail that does not require oversampling to achieve the size)?


Hub