Thumbnails API question
caulier.gilles at kdemail.net
Sun Sep 17 22:09:52 PDT 2006
On Sunday 17 September 2006 06:08, David Moore wrote:
> I suggest that the API just give the application a list of which
> thumbnails are available in the file along with their exact dimensions,
> and then the application will pick which one it wants and then request
> it. That seems like the most general approach.
I'm agree with David. we need exactly that into digiKam.
> On Sat, 2006-09-16 at 23:56 -0400, Will Stokes wrote:
> > Interesting question. From a developers stand point say I wanted a
> > 200x100 pixel thumbnail. I'd like to ask libopenraw to give me a
> > preview image ideally no less than 200x100 pixels in size. libopen raw
> > would then figure out the best preview image to give me. if non is
> > 200x100 it would give me the biggest one. if some are bigger it would
> > give me the smallest preview image that is at least 200x100 pixels in
> > size. libopenraw would not auto scale the image for me, that's my job,
> > as I might excel as faster or more accurate scaling depending on my
> > situation, or I might even want to wait to do scaling until I'm ready
> > to throw an image on teh screen, say if I'm eventually just loading it
> > as an OpenGL texture and mapping it to a quad.
> > Anyways, that's my two cents....
> > This is getting exciting. My first use of RAW will not be to allow the
> > user to edit/view full size RAW images but to throw thumbnails up in
> > my little EXIF/IPTC editor (Reveal). Currently I have some forked
> > forked dcraw code but if I could just use libopenraw to handle loading
> > thumbnails so much te better!
> > -Will
> > On 9/16/06, Hubert Figuiere <hub at figuiere.net> wrote:
> > > 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
> > > _______________________________________________
> > > Libopenraw-dev mailing list
> > > Libopenraw-dev at lists.freedesktop.org
> > > http://lists.freedesktop.org/mailman/listinfo/libopenraw-dev
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