Bug 367562

Summary:	Delay between brush/eraser or brush/previous brush(/) switch
Product:	[Applications] krita	Reporter:	Denis Moon <lloerau>
Component:	Tools	Assignee:	Krita Bugs <krita-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	halla
Priority:	NOR
Version First Reported In:	3.0.1 Alpha
Target Milestone:	---
Platform:	Neon
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Denis Moon 2016-08-19 12:44:42 UTC

There is a delay between switching brush/eraser and brush/previous brush with E and / shortcuts.
I've tried Instant Preview and Eraser Switch size turned on/off. No result.

Reproducible: Always

Steps to Reproduce:
1. Press B
2. Press either E or / and move the cursor.
3.

Comment 1 Halla Rempt 2016-08-20 09:27:51 UTC

Hi Denis,

I cannot reproduce this on OpenSUSE Leap with a home-built version of Qt 5.6. I've installed the latest neon build and checked which version of Krita is included, and that seems to be 2.9.7, so I'm unsure what you're actually running.

Comment 2 Denis Moon 2016-08-20 16:01:55 UTC

Hi Boudewijn,

I'm running KDE Neon 5.7 with Plasma 5.7.3, KDE Framework Version 5.25.0 and QT 5.7.0. My Krita is krita-3.0.1-Alpha2-d33dbe0-x86_64.appimage. Delay occurs also on Windows 10, as I tested it yesterday. Well, it is not a serious problem for me as the delay is only about 2-3 secs (may be someone won't consider this as a delay at all:), but it's certainly not what I remember from previous builds of Krita. I like testing all the new builds asap. Spending some hours with painting in Krita today, I can also say that there is a brush lag, noticeable if you try to change the brush size with holding SHIFT + cursor move. Resizing definitely works with a serious delay for me. It's not smooth either.

Comment 3 Denis Moon 2016-08-20 23:27:43 UTC

Hi again Boudewijn,

It looks as if I've found what is the problem. It's actually the KDE Compositor. When I set it to OpenGl 3.1, Krita's brush starts lagging a little bit. When I set it back to OpenGl 2.0, everything works just fine. Actually, I noticed some strange things using VLC with OpenGl 3.1, so I decided to change the Compositor, so I thought may be it would also solve my problem with Krita. It did. 
Well, sorry for bothering! And thank you! Problem solved!

Comment 4 Halla Rempt 2016-08-22 08:11:56 UTC

Well, not really solved if it also happens on Windows. I wonder if it's because of the cursor outline recalculation -- does it also happen for you if you disable the outline cursor? But on both my Windows and Plasma systems, I don't get any delay, no matter what the rendering backend setting in plasma is.

Comment 5 Denis Moon 2016-08-22 17:37:18 UTC

Hi again Boudewijn,

Yes, at the moment I'm experiencing the bug on Windows 10 only. KDE Plasma works now fine even with OpenGl 3.1 rendering backend. I have no idea why. The only thing I did with my Plasma was export __GL_YIELD=USLEEP to prevent video tearing with my Nvidia GTX 560 Ti. I don't know if it could affect this specific brush delay. I still notice some delays when I change brush size with SHIFT on KDE Plasma. But I can live with that. On Windows 10, it's worse. Brush delay using B>E and / shortcuts now is about 5 secs.

Comment 6 Denis Moon 2016-08-22 18:04:55 UTC

Sorry, I forgot to answer your question. Disabling the outline cursor makes no difference. At least, on Windows 10.