Grid-like pattern when rotating
GIMP version: 2.10.10
Operating System: Linux 3.18
Description of the bug
When rotating image using LoHalo and NoHalo interpolation the resulting image has grid/moire-like pattern. The pattern is very subtle and will most likely go unnoticed, but will become more (often very - when sharpening from RAW) pronounced once image has been sharpened. This obviously doesn't happen when cubic interpolation is chosen, and didn't happen on older Lanczos interpolation in 2.8 as well.
Reproduction
Is the bug reproducible? Always
Reproduction steps:
- Open any image (the best is unprocessed RAW) with large uniform area (like cloudless sky). The noisier the image, the more pronounced the final effect will be.
- Rotate it by any angle
- Sharpen
- Equalize to see the grid pattern.
Example: RAW image rotated by 1.11 deg, sharpened using legacy USM plugin with 0.1/3.60/2
Edited by Michael Schumacher