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Render only visible items.

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  • K Offline
    K Offline
    KrabQT
    wrote on last edited by
    #1

    If i have for example ListView with thousands items, i don't want them all to be processed, because it will hurts perfromance.
    I read that i could setup the visible property to false, but i would better do something similiar to when using QPainter to paint items.
    With QPainter if i know that widget height is 100 and i have 1000 items where each has 10px, i can easily to calculate which items to paint based on where scrollbar is, so it is very fast. How to do this in Qt Quick 2? Actually i don't want even to use that QML (i don't want the javascript engine to slow down the app), i wanna to use C++ for everything. I expect some method where i can add to Scene Graphs just items that are visible (which i will calculate based on height etc..), but can't find where to do it.

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    • K Offline
      K Offline
      KrabQT
      wrote on last edited by KrabQT
      #2

      As i went through source code of qdeclarative, i noticed that it is even not possible to add for example text node programatically, so i think best way for me will be to fork qdeclarative so i can use even those private classes and do what i need.

      p3c0P 1 Reply Last reply
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      • K KrabQT

        As i went through source code of qdeclarative, i noticed that it is even not possible to add for example text node programatically, so i think best way for me will be to fork qdeclarative so i can use even those private classes and do what i need.

        p3c0P Offline
        p3c0P Offline
        p3c0
        Moderators
        wrote on last edited by
        #3

        @KrabQT Sounds like a good opportunity for QAbstractItemModel with ListView. Re-Implement fetchMore and canFetchMore for incremental model.

        157

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