On Android systems, if brush strokes were painted when the canvas is highly zoomed-out, they appear jittered at 100%, as if they were interpolated with a very low resolution. Steps to reproduce" 1) Create a new document, A4 300ppi; 2) Zoom out the canvas to something lower than 12.5%; 3) Paint some small circles (approximately 5cm in diameter) 4) Zoom in to 100% Expected result: The brush strokes should appear smooth at 100%. Actual result: The brush strokes appear very jittered and unusable. Tested on: Samsung Galaxy Tab S8 (OneUI 6.1.1/Android 14) Also confirm by other community users with Galaxy Tab S7 I will attach some examples on the following comments.
Created attachment 178972 [details] Krita brush strokes jitter when painted zoomed out
Created attachment 178973 [details] Brush strokes painted on Linux when zoomed out This screenshot was captured on the Linux version using the same procedure and they look smooth and fine. I deliberately tested this one on a Wacom One 13, which share the same Wacom EMR Pen technology with the Samsung Galaxy Tab S7 and S8 (all devices can share the same stylus). So I think we can rule out the possibility of low hardware resolution. Reportedly, other art apps on Android are not affected by the same bug.
I have also tested this bug with Krita 5.2.9 and the latest nightlies. All of them are affected on Android.
Correction: In the original description, Step 3) Paint some small circles (approximately 5cm in diameter) It should be 5mm (which will resulted in extreme staircase like aliases). And we have also tested this on Tab S7FE, S9+ and S9U.
Created attachment 178974 [details] Extreme jitter if zoomed out to less than 12.5% and painted with smaller than 5mm circles
I can reproduce this both with a Samsung S-Pen and a Wacom Intuos tablet. However, this is because Android just doesn't have high-resolution input. The reason other applications appear smoother is, from what I can tell, that they always compensate for low-frequency input and build a smooth curve, which as far as I can tell Krita does when you turn on the "Basic" brush stabilizer, resulting in a similarly smooth result. When I move the pen slowly in Ibis Paint or Drawpile, I get the same staircase effect, which shows that they're not receiving inputs at a higher resolution either. So this needs to be fixed upstream, either the tablet manufacturers or Android would need to improve the input resolution. Users can enable a brush stabilizer to compensate for it in Krita.