Bug 399638

Summary:	Noticeable lag when drawing
Product:	[Applications] krita	Reporter:	Wontoon <WontoonRoo>
Component:	Tablets (tablet issues are only very rarely bugs in Krita!)	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	halla
Priority:	NOR
Version First Reported In:	4.1.3
Target Milestone:	---
Platform:	Other
OS:	Microsoft Windows
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Wontoon 2018-10-11 04:01:26 UTC

SUMMARY
After the October 2018 update on Windows 10, when drawing with a Cintiq Pro 16 tablet (this may extend to all Wacom tablets; unsure) there is a noticeable delay (around 1 ~ 1.5 seconds) between when the the pen is on the canvas and the stroke appears on the canvas. This appears in both Krita 4.1.1 and 4.1.3, and both tablet input APIs. This seems to be somewhat sporadic, but it definitely happens very, very often.

On the Surface 4 Pro, this problem does not exist (I have tested 4.0, got the Cintiq Pro shortly after-- and 4.1.3. I expected 4.1.3 to have the same issue but it is not there, making me conclude that this is possibly isolated to Wacom tablets).

STEPS TO REPRODUCE
1. Run Krita after the October 2018 update for Windows 10.
2. Make a line. It may take a few lines.
3. (Optional) Curse at Microsoft at the top of your lungs.

OBSERVED RESULT
Lag in strokes appearing on screen.

EXPECTED RESULT
Smooth drawing.

SOFTWARE VERSIONS
(available in About System)
4.1.1, 4.1.3

KDE Plasma Version: N/A
KDE Frameworks Version: N/A
Qt Version: 5.9.3

ADDITIONAL INFORMATION
OS Information
  Build ABI: x86_64-little_endian-llp64
  Build CPU: x86_64
  CPU: x86_64
  Kernel Type: winnt
  Kernel Version: 10.0.17134
  Pretty Productname: Windows 10 (10.0)
  Product Type: windows
  Product Version: 10

Comment 1 Halla Rempt 2018-10-11 08:04:42 UTC

Did you enable the stabilizer?

Comment 2 Halla Rempt 2018-10-12 10:25:42 UTC

Set to waiting for info.

Comment 3 Wontoon 2018-10-13 05:41:56 UTC

(Sorry for the delay, was worn out from work I didn't even check my messages!)

I don't remember ever enabling it (I am assuming "Basic" is the default setting?), but the "Brush Smoothing" is set to "Basic". Setting it to "none" showed some(?) improvement, but the sporadic lag is definitely still there (just not as harsh). I've also noticed that, if your pen is away from the tablet for a while and you try to make a stroke, the first stroke will not appear. Subsequent strokes will appear, though! It is definitely consistent with that, too.

I also double-checked the Surface 4 and the Brush Smoothing setting is set to "Basic" as well, and as expected the sporadic lag does not exist on there.

Comment 4 Wontoon 2018-10-14 08:59:52 UTC

So an update to the issue:

After closing Firefox because it was being unstable (the whole system was lagging like crazy and I figured that was the cause, and I was right when I closed Firefox), the issue... somehow resolved itself. Reopened it to confirm if Firefox was the issue, but I could not seem to replicate the lag.

Huh.

(This is even more confusing since I immediately encountered the lag after the restart and it persisted until now. Firefox is still going, and the lag is still absent...)

Comment 5 Halla Rempt 2018-10-14 09:14:57 UTC

I think we'll have to write this down to system weirdness... It's not something we can investigate or code a fix for, I think.