Forum: Ruby on Rails Attachment_fu ImageScience FreeImage thumbnail quality

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00973881979aa0a660ffbbb2f7a907fb?d=identicon&s=25 Peter De Berdt (Guest)
on 2007-02-07 00:59
(Received via mailing list)
I've tried migrating acts_as_attachment to attachment_fu (just to see
if I could replace RMagick with ImageScience+FreeImage), but the
quality of the thumbnails is just horrendous, blurred beyond
recognition (downscaling a 1280x1024 to a few considerably smaller
thumbnails).
Changing attachment_fu to use RMagick again and the thumbnails were
crispy sharp again.

I was wondering if this has anything to do with ImageScience or if
it's rather just FreeImage not using a good scaling algorithm.


Best regards

Peter De Berdt
6b3d7ffaa5e30c4d2609a27cc52802fb?d=identicon&s=25 Ben Mabey (Guest)
on 2007-02-07 06:45
(Received via mailing list)
Peter,

Check out this blog's comments:
http://mephistoblog.com/2007/1/9/new-asset-thumbna...

From the link:
"ImageMagick's default resampling filter used for image resizing is the
Lanczos filter. For Image Science it's bilinear filter. Bilinear is
faster
but it's not the best for creating thumbnails of photographic images.
It's
only possible to set Lanczos as the default by patching FreeImage
source.
It's pretty straightforward though Â…"
....
"Martins: That decision came up when I asked Ryan Davis to include the
resizing functions in ImageScience. He was dead set on keeping the gem
simple, so decided to hardwire the filter choice. It may be worth being
able
to override it in Ruby without having to hack c though."
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