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.
“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 ”
…
“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.”
