Bug 427376

Summary: Gradient map filter layer very slow. Maybe only for windows.
Product: [Applications] krita Reporter: Hector <misha.bossmass>
Component: Filter LayersAssignee: Krita Bugs <krita-bugs-null>
Status: RESOLVED FIXED    
Severity: normal CC: halla
Priority: NOR    
Version First Reported In: 4.4.0-beta2   
Target Milestone: ---   
Platform: Microsoft Windows   
OS: Microsoft Windows   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:

Description Hector 2020-10-06 09:01:22 UTC 
I have fx 8350 and rx 560. Windows 10 pro 64-bit. Usually I use Krita plus, but now I checked it on different versions.

 I have a very bad gradient map. In 8-bit it is tolerable, but in 16-bit it takes too long.
 What it looks like. I am creating a filter layer. Nothing happens. i choose a gradient. Nothing. I can't press anything in Krita either. After a couple of minutes, the result of the first gradient begins to be shown, which opens by default (foreground color to transparency). And only after its complete processing, the calculation of the second selected gradient begins.

 Color space is not affected. 8-bit or 16-bit, yes very much. Direct3d and opengl seem to work the same way. The filter layer in the group gets even slower. The filter brush with gradient map doesn't work well either. But I do remember that when I experimented with the brush filter before, it worked quickly. 

 Perhaps this is something with Windows. I checked on a linux VM. (mint mate) And there it works. In 16-bit it is still slow, but in 8-bit I can draw in real time. In the virtual machine!
So what else do I need to check?
Comment 1 Hector 2020-10-06 09:31:44 UTC 
I have a 2000 x 2000, 8-bit layer. I click on add a layer filter with a gradient map already set. It starts to calculate the default gradient (forground to transparency). In beta2 on Windows, it takes 13.5 seconds to fully update the preview. On a Linux virtual machine 4 sec. After I can draw on a Linux virtual machine and the colors are immediately updated.
In 16-bit, on Windows 1 min 15 sec. On Linux virtual machine 30 sec
Comment 2 Hector 2020-11-02 12:03:30 UTC 
Testing Build #1138 (Nov 2, 2020 8:18:00 AM)   https://binary-factory.kde.org/job/Krita_Nightly_Windows_Build/1138/ 
The same setting. 2000 x 2000, 8 bit. I choose a gradient in the filter layer. Now it takes ~3 seconds for a complete calculation. No lags, no freezes. The filter mask in the group is faster than the filter layer. There is still no real time. but turns on and off very quickly.

The Gradient Map Brush(filter brush engine) is now freezing the app.

The performance has improved.
Comment 3 Halla Rempt 2020-11-02 12:18:16 UTC 
Yes, this was done in https://invent.kde.org/graphics/krita/-/merge_requests/560, commit 27ca01b463b778a3f1302ca6c9b36f549fe46f9e
Comment 4 Halla Rempt 2020-11-02 12:18:38 UTC 
The brush engine needs a separate bug report, though.