filmic: surprising slider behavior related to sanitization
When moving the "middle grey luminance" slider, the "black relative exposure" is sometimes changed, probably to avoid some inconsistencies.
The problem is that when moving the "middle grey luminance" slider back to its initial position, the black slider doesn't come back to the initial position.
- Click "auto-tune levels". Black and white levels are OK.
- Try a light part of the image with the "middle grey luminance" picker. The dark slider is sanitized.
- Try another part of the image. Now, the dark slider is wrong.
Actually, since the effect of the picker is continuous, this can happen while drawing a single rectangle area with the picker: if one starts the rectangle from a dark pixel, the black cursor will be moved before finishing the rectangle.
One solution would be to keep two values per slider: the sanitized one and the user-defined one. Moving the slider would set both values, and the sanitized one would be the one displayed on the GUI and used in the processing, but the user-defined one would be the starting point for sanitization.
#1 Updated by Aurélien PIERRE about 1 year ago
- System changed from Ubuntu to all
- % Done changed from 0 to 70
- Status changed from New to Patch attached
That's the limit of trying to automatically clean-up the randomly harmful parameters users might input. My last PR has relaxed the constraint over the black exposure and the dark slider will not be sanitized anymore. https://github.com/darktable-org/darktable/pull/1893