Here is a cubic (catmull-rom) resizing filter for farbfeld: https://github.com/ender672/farbfeld-resize
Example usage is: $ jpg2ff < in.jpg | ./resize 123 456 | ff2png > out.png The arguments indicate the desired maximum height and width. The image above will be resized to fit inside a 123x456 box while preserving the aspect ratio. It has no external dependencies, but includes a single-file library to perform resampling. Interpolation happens with 8-bit components, so this filter truncates 16-bit colors to 8-bit, resamples, and then scales 8-bit colors back up. I could look into supporting 16-bit colors in the interpolator, but would be curious what the use cases are first.
