Bug 378846 - If canvas is zoomed out, brushes get very slow
Summary: If canvas is zoomed out, brushes get very slow
Status: RESOLVED WORKSFORME
Alias: None
Product: krita
Classification: Applications
Component: OpenGL Canvas (show other bugs)
Version: 4.2.8
Platform: Microsoft Windows Microsoft Windows
: NOR normal
Target Milestone: ---
Assignee: Krita Bugs
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2017-04-16 20:29 UTC by Storm Engineer
Modified: 2020-03-12 13:11 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Demonstration of issue (165.79 KB, image/jpeg)
2017-07-07 21:14 UTC, Storm Engineer
Details
Comparison of zoom levels with a 1000 by 1000 test image (131.86 KB, image/jpeg)
2017-07-07 21:14 UTC, Storm Engineer
Details

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Description Storm Engineer 2017-04-16 20:29:04 UTC
Since recently, if I zoom out on a large canvas, brushes start to feel like they are sticking to the canvas, drawing very slowly, even if the brush size is still small.

OpenGL enabled
Toggling Instant Preview makes no difference

Arch Linux + Plasma 5
Krita built from master
Comment 1 Raghavendra kamath 2017-04-18 12:57:53 UTC
I am on arch linux plasma 5 with krita built from source. I couldn't reproduce the issue. I could paint with small brush on a relatively large canvas 7k X 7k with ease and without any noticeable delay in zoomed out canvas as compared zoomed in one.

Can you please specify steps to reproduce this. The size of the canvas and name or typeof brush preset would be a good information.
Comment 2 Storm Engineer 2017-04-21 15:14:54 UTC
(In reply to Raghavendra kamath from comment #1)
> Can you please specify steps to reproduce this. The size of the canvas and
> name or typeof brush preset would be a good information.

I recorded a video demonstrating the issue. Here is a Dropbox link to that, plus the brush I used, the test file and my kritarc:
https://www.dropbox.com/sh/522okznrywfy7b9/AAB2g9rJFHs60BuWkodiz-MYa?dl=0
Comment 3 Halla Rempt 2017-04-25 09:19:55 UTC
Which opengl driver are you using? Looks like it has problems updating the projection.
Comment 4 Storm Engineer 2017-07-07 21:14:20 UTC
Created attachment 106494 [details]
Demonstration of issue
Comment 5 Storm Engineer 2017-07-07 21:14:57 UTC
Created attachment 106495 [details]
Comparison of zoom levels with a 1000 by 1000 test image
Comment 6 Storm Engineer 2017-07-07 21:31:26 UTC
(In reply to Boudewijn Rempt from comment #3)
> Which opengl driver are you using? Looks like it has problems updating the
> projection.

Sorry for not answering, I simply forgot I made a ticket already. O_o Now I found it...

I know nothing about OpenGL - I use the proprietary nvidia drivers, hopefuly this is what you were asking. Installed packages (on Arch):

cuda 8.0.61-2
lib32-libvdpau 1.1.1-2
lib32-nvidia-utils 381.22-1
libvdpau 1.1.1-2
libxnvctrl 381.22-1
nvidia 381.22-4
nvidia-settings 381.22-1
nvidia-utils 381.22-1
opencl-nvidia 381.22-1


Krita settings:

OpenGL: Enabled
Filtering: Trilinear
Use texture buffer: Enabled


I also added some images demonstrating the issue.
Comment 7 Halla Rempt 2017-11-26 13:12:49 UTC
Dmitry says that either brush smoothing is enabled, which we cannot see because the tool options palette is not visible in the video, or it's the way the brush works -- smudge brushes are always slower than pixel brushes, especially if the stroke gets longer (which happens here, because if you zoom out, you paint along a longer path).

But there isn't much we can do with this report, I'm sorry to say. We're always trying to make Krita perform better, but this doesn't point to any specific place where we can change things.
Comment 8 Storm Engineer 2017-12-18 05:25:43 UTC
Yes I use smoothing but is it normal that it gets extremely laggy from zooming out?
Comment 9 Storm Engineer 2017-12-18 05:29:17 UTC
I played around with Stabilizer. Unticking "scalable distance" made the lag go away.

I'm just curious if it is normal behavior that it lags so much with scalable on a large canvas.
Comment 10 Halla Rempt 2017-12-18 10:38:31 UTC
Yes, that's how the stabilizer works.
Comment 11 Tiar 2020-03-12 13:11:19 UTC
@hibaguimri0@gmail.com If you have issues with brushes, please go to one of the user support forums first, either krita-artists.org, KDE forum: https://forum.kde.org/viewforum.php?f=136 or reddit.com/r/krita . Do not reopen bug reports that were determined to be invalid three years ago - it doesn't make sense, your issue is probably very different, and if not, then it's a user support issue, not a bug. If you're not sure, on the user support forum supporters will help you with the process of reporting bugs or just help you fix your issue. Thanks!