Resizing windows is slow with Qt 5.10

[bunjee207]

Greetings Qt dev,

I'm in the process of porting my Qt 4.8 QML code to Qt 5.10 on the Windows platform and the OpenGL backend.

For some reason resizing windows is significantly slower using Qt 5. It's been the case since the beginning of Qt 5 and it's honestly quite awful.

Is there any workaround or flag to improve the situation ?

Thanks ♥.

[mrjj]

Hi
Its impossible to guess at without actual code.
Lots and lots has happened from 4.8 to 5.10 so it depends on
what features u are using etc.

[bunjee207]

I see your point except I get the same behavior with a generic Qt sample.

It's clearly something low level regarding Windows implementation and OpenGL rendering.

[JKSH]

@bunjee207 said in Resizing windows is slow with Qt 5.10:

I get the same behavior with a generic Qt sample.

Could you please specify the sample, or share some simple code that demonstrates this issue?

Also:

1. Which version of Windows are you running?
2. What is your graphics card?

[bunjee207]

Well, you could try the "samegame" demo.

I'm on Windows 10, with an Intel HD Graphics 4600.

Besides being slow resizing is also glitchy: https://bugreports.qt.io/browse/QTBUG-67029

[mrjj]

Hi
Most likely related to intel HD. i assume you tried update drivers?
Sample seems to run normally on AMD 7950 card. ( Qt 5.10, vs, win 10)
No lag in 1900x1200.

[JKSH]

@bunjee207 said in Resizing windows is slow with Qt 5.10:

Well, you could try the "samegame" demo.

I'm on Windows 10, with an Intel HD Graphics 4600.

Besides being slow resizing is also glitchy: https://bugreports.qt.io/browse/QTBUG-67029

I have a Microsoft Surface Pro 2, Windows 10 x64, Intel HD Graphics 4400, 1920x1080 resolution.

I built and ran the Same Game demo using Qt 5.9.4, MinGW 5.3.0.

The game itself runs perfectly fast and smooth. When resizing the game window, I see some minor flickering but it feels fast to me. Also, resizing the Same Game window feels exactly like resizing the Microsoft Word 2016 window, so the flickering is not caused by Qt Quick.

I don't see any problems with resizing Qt Quick windows on my machine. Do you have a different Windows 10 PC available? Could you try there?

[6thC]

@bunjee207
I have a HD Graphics 530 and have noticed the same lag resizing, it's probably the biggest visual wart I see.
At this point we were planning on not allowing the user to resize. Maybe reconsider this is it works better on other hardware, probably not though.

Windows 10 Pro, MinGW 5.3.0, Qt 5.10.0

• MSVC17 compiler builds do not run (or rather, crash in OpenGL calls) on drawing.

Video: https://drive.google.com/file/d/11KnuAC76A4-4FLFggN_1rS9dP3Rl0c5P/view?usp=sharing
hopefully that link works