Extrapolation is enabled by default
3.36.2 as shipped by Fedora 32
Steps to Reproduce
- Open an image file in EOG
- Zoom-in (to any zoom level lower than 100%)
The zoomed-in image is normal (pixelated) for a short moment, but then suddenly becomes blurry.
The zoomed-in image is displayed as normal with no change.
Originally there was a single setting for interpolation and extrapolation. The extrapolation setting has been introduced after discussion in a bug report. The original motivation for this split was that extrapolation (zoom-in smoothing) was not considered useful in opposite to interpolation (zoom-out smoothing). Despite that, in the end the extrapolation was set to be enabled by default "to keep the initial behaviour as in previous eog versions."
I'm not aware of a practical usefulness for extrapolation in an image viewer application. I don't think it looks pretty either. Maybe a different extrapolation formula would look better, but why not just disable extrapolation by default?