bicubic interpolating zoom

[Boudewijn Rempt]

On Sunday 15 August 2004 22:45, Michael Thaler wrote:
>
> Actually I thought a lot about the whole scaling issue on my trip to
> Vienna. Enlarging an image is really not that hard and you can easily get
> anti-aliasing working. But scaling an image down is much harder. Just
> imagine to scale an image down to 25% of its original size. This means that
> each 4x4 pixel block becomes a single pixel. Now there are many strategies
> how to do that: you could just average over them which would probably work
> nicely for photos. But this will fail for e.g. a page of scanned text
> because you would end up with a grey page. I think scaling images down is
> really hard and I will try to look at the Gimp's source code and try to
> figure out how they do it.
>

Downscaling is indeed much more interesting than upscaling: it's used more 
often, for instance in preparing screenshots for Krita's website :-).

-- 
Boudewijn Rempt | http://www.valdyas.org/fading/index.cgi
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://mail.kde.org/pipermail/kimageshop/attachments/20040816/e3b168ca/attachment.pgp