Bug 1214915 - Please build Qt5 with configure option -xcb-native-painting
Summary: Please build Qt5 with configure option -xcb-native-painting
Status: RESOLVED FIXED
Alias: None
Product: openSUSE Tumbleweed
Classification: openSUSE
Component: KDE Applications (show other bugs)
Version: Current
Hardware: Other Other
: P5 - None : Normal (vote)
Target Milestone: ---
Assignee: E-Mail List
QA Contact: E-mail List
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Reported: 2023-09-03 20:16 UTC by André Wöbbeking
Modified: 2024-01-03 18:00 UTC (History)
2 users (show)

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Description André Wöbbeking 2023-09-03 20:16:40 UTC
Hi,

this is an experimental feature to let Qt5 paint as Qt4 did. This improves performance of Qt5 applications under X2Go a lot.

First this option was enabled by default but some years later it was disabled to reduce the size of the platform plugin libqxcb.so a little bit.

You don't have to worry that you brake something if you enable this option as the user also have to set the environment variable QT_XCB_NATIVE_PAINTING to make it work.

Thanks in advance!

Cheers,
André
Comment 1 Fabian Vogt 2023-09-21 13:31:56 UTC
> You don't have to worry that you brake something if you enable this option as the user also have to set the environment variable QT_XCB_NATIVE_PAINTING to make it work.

Indeed, but then I wonder why it's not enabled by default upstream. Do you know?

It looks like this is available in Qt 6 as well (also still experimental), so if we enable this in Qt 5 it should be done for Qt 6 as well.
Comment 2 André Wöbbeking 2023-09-21 21:30:21 UTC
Hi,

> Indeed, but then I wonder why it's not enabled by default upstream. Do you know?

here is the commit:

commit 7f948d9effad983477977c3274231401f260c531
Author: Eirik Aavitsland <eirik.aavitsland@qt.io>
Date:   Thu Jul 4 13:56:44 2019 +0200

    Disable experimental xcb native painting config option by default
    
    Saves 13% on the binary size.

FYI, on Tumbleweed the size of libqxcb.so is 18616 bytes.

> so if we enable this in Qt 5 it should be done for Qt 6 as well.

Why not, it could also help some people.

Cheers,
André
Comment 4 Christophe Marin 2023-10-07 15:21:10 UTC
https://build.opensuse.org/request/show/1116104

The qt6-base change is already in tumbleweed.
Comment 5 André Wöbbeking 2023-10-10 19:38:34 UTC
Thanks, I just realized that I also use Qt6 with QtCreator :-)

And right now Qt5 arrived in Tumbleweed, e. g. "find /" in konsole in X2Go just flies.

Cheers,
André