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Performace Problem with Text



  • Hello there,

    at the moment i struggle with some Performance Problems of my App I Develop in QML.

    I generated a new example Qt Quick-UI so demonstrate my problem

    @import QtQuick 2.2

    Rectangle {
    width: 360
    height: 360
    Text {
    anchors.centerIn: parent
    text: "Hello World"
    }
    MouseArea {
    anchors.fill: parent
    onClicked: {
    Qt.quit();
    }
    }
    }@

    The Problem is, that the generating of the Text takes 1.808s
    Heres a Screenshot of the QML-Profiler:
    !http://ngleichauf.de/download/screen.png(Screenshot)!

    How can i fix this issue?

    Thanks


  • Moderators

    You are asking about initialisation performance: I doubt you can do anything there.

    Please try with changing "renderType":http://qt-project.org/doc/qt-5/qml-qtquick-text.html#renderType-prop property. It can have big impact on runtime performance, although I doubt it will change much in the initialisation time.



  • Oh i forgot to mention that I already tried to set the renderType.
    This Code changes nothing. The Time is 1.811s.

    @import QtQuick 2.2

    Rectangle {
    width: 360
    height: 360
    Text {
    anchors.centerIn: parent
    text: "Hello World"
    renderType: Text.NativeRendering
    antialiasing: false
    smooth: false
    }
    MouseArea {
    anchors.fill: parent
    onClicked: {
    Qt.quit();
    }
    }
    }@

    My sytem is Mac OS X 10.9.2 on on MacBook Pro Retina 2012



  • Hi, I tried your example on windows and it takes like 20 ms to create the Text element. Still by far the slowest item but nothing compared to your time!?

    !http://i60.tinypic.com/r2kfa8.jpg(qml profiler)!



  • I just tested it on Windows 7 too.
    The time is 5.2 ms this would be all right. But almost 2 seconds? I don't understand what im doing wrong.



  • I think there has been reported performance issues in particular when loading the QFontDatabase data at startup, which would have no relation to rendering time. That said I have never heard about performance as bad as this so it might be worth reporting.
    A few points though:

    • make sure you don't compare performance using a debug build
    • if its the font database this should be a one time cost. Consecutive instances for Text would be much faster.
    • the amount of fonts installed might affect the performance. Do you have a lot of fonts installed on the mac?


  • Thanks for your answer and your hints.
    I think you are right. Further texts do not impact the Time in the way the first does.
    !http://www.ngleichauf.de/download/screen2.png(screenshot)!

    I now don't have any additional fonts installed on my Mac, i ensured it and deleted all the additional fonts i installed.

    The problem is also there if I build the release of the program.

    Also if it is a one time cost to load the font database it takes much to long in my opinion, in which the problem is not there when using windows.

    I use a splash screen at the moment to load the main content in background, but this is only necessary because the first text loads this long.

    Thanks!
    Greets Nico



  • Hey,

    i just installed the 5.3.0 RC.
    The problem is solved with this release.

    Thanks!

    Greets Nico


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