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  1. Qt
  2. QTBUG-101669

Low framerate using PinchArea/PinchHandler

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Details

    • Bug
    • Resolution: Unresolved
    • P3: Somewhat important
    • None
    • 5.15, 6.3.0 Beta2
    • Quick: 2D Renderer
    • None
    • Windows 11 on Acer Spin 5 with 11th generation i5
      Windows 11 Galaxy Book 10.5 inch
    • Windows

    Description

      This is something I've been noticing for quite some time in Qt Quick applications. When using a a PinchArea or PinchHandler, the frame rate of the qt quick scenegraph seems to unexpectedly drop to about 30fps. I can reproduce the problem with the following code:

       

      import QtQuick 2.15
      import QtQuick.Window 2.15
      
      Window {
          width: 640
          height: 480
          visible: true
          title: qsTr("Hello World")
      
          Rectangle{
              width: 400
              height: 500
              color: "green"
              PinchHandler{}
          }
      }
      

      The issue can be reproduced by repeatedly pinching in and out, this causes some drops in frame rate (I've tested in Release mode obviously). Other animations like scrolling don't suffer from the issue from my testing. I've also logged the scenegraph events by enabling qt.scenegraph.time.renderloop and I have attached a logging sample of the events pinchlog.txt

      I couldn't reproduce the issue with a 100% reliability, but it occurs frequently enough.

       

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            janichol Andy Nichols
            daljit97 Daljit Singh
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            Dates

              Created:
              Updated: