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Window scaling very slow



  • Whatever I create in PyQt scales very slowly. What I mean is, when I resize the application window, its contents refresh to the new size with a significant delay. It can be 1-2 seconds.
    Also, when I created a browser and ran a php-based image galleryon it, the images were displayed super slowly. On any other browser it was fine.
    I'm running on Windows 7, but it's slow on Win 10 too. Does the app need to be optimized for Windows somehow?
    I don't have an example code, because this affects any app that I make, with or without QWebEngine.


  • Lifetime Qt Champion

    Hi,

    Which version of Qt ?
    How did you install it ?
    Which version of Python ?
    What are you machine spécifications ?



  • @SGaist said in Window scaling very slow:

    Hi,

    Which version of Qt ?
    How did you install it ?
    Which version of Python ?
    What are you machine spécifications ?

    Hello! Here is the info. I installed everything in the PyCharm IDE, using terminal and pip install.

    Python 3.8
    PyQt5 5.15.4
    PyQt5-Qt5 5.15.2
    PyQtWebEngine 5.15.4
    PyQtWEbengine-Qt5 5.15.2

    System:
    Windows 7 64bit, Intel i5-6400, 8GB RAM, Geforce GTX 960, SSD disk


  • Lifetime Qt Champion

    Did you check the NVIDIA driver ?



  • @SGaist said in Window scaling very slow:

    Did you check the NVIDIA driver ?

    Sorry for a late reply.. my driver is fine. I tried my app at school and it was a bit faster, because they have a very powerful computer there.
    If you want to see what I'm talking about, try using this php image gallery here:
    https://makitweb.com/demos/make-photo-gallery-from-image-directory-with-php
    The photos open up pretty fast, right?
    Now, make a PyQt browser and open up this same site in your browser. Should be a lot slower now. At least it is for me.


  • Lifetime Qt Champion

    Can you provide a minimal script that allows to reproduce this behaviour ?



  • @Harborman , I noticed something similar on Win10 for my app recently. I would like to ephisize 'recently' here - I have an application that I use on Linux mostly and on Windows occasionally. And I haven't had problems with performance on Windows.

    Last week I created another simple app on Windows and noticed that window resizing happens rather slowly. As I didn't have problems before I suspect that problem lies in application code itself. For this particular simple app I have only 1 widget in main window but this widget is big QTableView with custom colors that are choosen with not optimized db queries. So, I would bet that my problem is due to slow painting of the widget.

    Now, sorry for a lot of words, but I wanted to illustrate that there might be a problem with what you show in you app.
    Nevertheless, I'll try to run my old app on this Windows system and update you with test result - is it slow or not.


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