Sven Neumann wrote:
> after spending quite some time with the new scale code, I have some
> doubts about the way that it is scaling down. So here's a patch that I
> am playing with at the moment:
> This patch applies against SVN trunk. It only changes the current
> behavior when scaling the image down. The strategy it applies is that
> for scale ratios < 0.5, the image is decimated using a simple box filter
> until it has a size that is only up to two times larger than the desired
> size. At this point the standard interpolation algorithm is used to
> scale the image to the final size. Of course for interpolation-none, no
> box filter is used, but the nearest pixel is chosen.
> I haven't done much testing with this patch yet, but overall it seems to
> give better results than the code that is currently in trunk (and it is
> a little bit faster). However, there are some corner cases like the
> Moire rings in http://svenfoo.org/scaletest/12-6.html where the results
> are worse.
> If someone is interested, please apply the patch and try some of the
> problematic images in the previous scaletest. Your feedback is very much
> Gimp-developer mailing list
What are your doubts with the new code? Why would a simple box-filter be
better for decimating?
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