This was caused by allowing the stage to be set to fractional coordinates. For example, the stage might be positioned at `x: 142.22255, y: 488.79`.
When positioned like this, the canvas will be slightly misaligned with its native pixel grid. The browser does its best, but this causes tiny scaling artifacts throughout the image. It's most noticeable where there is a sharp contrast.
This behaviour was introduced while troubleshooting an issue with degraded quality when saving canvas to gallery. Turned out the stage position was unrelated to that issue, but I didn't realize that the change would cause this other type of problem.
The fix is super simple - ensure we floor stage coords when setting the manually. Konva never sets the position to fractional coordinates itself. For example, while dragging the stage, Konva sets the stage coordiantes itself, and they are always integers.
- Canvas manages its own progress socket event listeners and progress event data.
- Remove cancellations listener jank.
- Dip into low-level redux subscription API to watch for queue status changes, clearing the last "global" progress event when the queue has nothing in progress. Could also do this in a useEffect I guess.
- Had to shuffle some things around to prevent circular imports, so there are a lot of tiny changes here.
- Remove queue front button. Hold shift while clicking `Invoke` button to queue front.
- Restore queue menu actions w/ the reclaimed space.
- Simplify queue interaction hooks.
The lineart model often outputs a lot of almost-black noise. SD1.5 ControlNets seem to be OK with this, but SDXL ControlNets are not - they need a cleaner map. 12 was experimentally determined to be a good threshold, eliminating all the noise while keeping the actual edges. Other approaches to thresholding may be better, for example stretching the contrast or removing noise.
I tried:
- Simple thresholding (as implemented here) - works fine.
- Adaptive thresholding - doesn't work, because the thresholding is done in the context of small blocks, while we want thresholding in the context of the whole image.
- Gamma adjustment - alters the white values too much. Hard to tuen.
- Contrast stretching, with and without pre-simple-thresholding - this allows us to treshold out the noise, then stretch everything above the threshold down to almost-zero. So you have a smoother gradient of lightness near zero. It works but it also stretches contrast near white down a bit, which is probably undesired.
In the end, simple thresholding works fine and is very simple.
