06-15-2018, 09:28 PM
(This post was last modified: 06-15-2018, 09:29 PM by BertyCraitbgoe.)
(06-15-2018, 08:50 PM)Ofnuts Wrote:(06-15-2018, 12:59 PM)BertyCraitbgoe Wrote: Thanks so much for looking into that for me, it definitely gives a much better result (just tested it). Is some degradation in quality to be expected from using the rotate tool? It's just I've never noticed it before when using previous versions.
All the transform tools (Except Move & Flip) have to interpolate pixels. This will always degrade the image (even if some interpolation algorithms are better than others). This is more visible on sharp edges of text and logos(*). Degradation is cumulative, if you chain several such transforms the final result can be blurry (which is one of the purposes of the new "Unified transform tool"; you can do all the transformation in one call, so there will be only one single interpolation).
(*) Because the edges are made of anti-aliasing pixels. And the interpolation of the anti-aliasing pixels by a given transform doesn't produce exactly the anti-aliasing pixels for the tranrformed edge. This is also why, when working with text and logos, it is better to apply the tools to the *path* and then redraw/pain the logo/text using the transformed path.
Thanks. I just used the text as an example to show it up, I was actually working on a photo when I first noticed it. It's good to know these things because now I can plan for them in advance to save losing quality in the long run. (I noticed that adding some slight sharpening from G'MIC helped counteract some of the ill effects, but I'd rather just minimise the degradation period.)