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  1. Qt
  2. QTBUG-85140

[REG 5.13 -> 5.14] No longer possible to shallow copy QVector<QPointF> to and from QML

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Not Evaluated
    • Resolution: Out of scope
    • Affects Version/s: 5.14.2, 5.15.0
    • Fix Version/s: None
    • Labels:
      None
    • Platform/s:
      Linux/X11, Windows

      Description

      Since https://bugreports.qt.io/browse/QTBUG-80916 was fixed there is severe performance impact when using QVector<QPointF> with QML in Qt 5.14.2 and Qt 5.15.0.

      Emitting QVector<QPointF> from C++ to QML and from QML to C++ happens instantaneously in Qt 5.13.2.

      Attached program 'Charting.tar.gz' track the time needed to generate QVector<QPointF> in one plugin and plot the data through another. It take ~1 millisecond to plot 10 millions points after they are generated  in Qt 5.13.2 and ~7000 milliseconds in Qt 5.14.2 and Qt 5.15.0.

      Screen shot 'QVector_QPointF_regression.png' showing the program running with Qt 5.13.2, Qt 5.14.2 and Qt 5.15.0 is attached as well.

        Attachments

        1. Charting.tar.gz
          4 kB
        2. FastCharting.png
          FastCharting.png
          93 kB
        3. FastCharting.tar.gz
          4 kB
        4. QVector_QPointF_regression.png
          QVector_QPointF_regression.png
          86 kB
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          Activity

            People

            Assignee:
            qt.team.quick.subscriptions Qt Quick and Widgets Team
            Reporter:
            malyar Viktor Malyarchuk
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            Watchers:
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              Dates

              Created:
              Updated:
              Resolved:

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