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  1. Qt
  2. QTBUG-38570

QtQuick scrolling behavior erratic with XInput2 high-precision scrolling

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    Details

    • Type: Bug
    • Status: Open
    • Priority: P4: Low
    • Resolution: Unresolved
    • Affects Version/s: 5.3.0 Beta1, 5.3.1
    • Fix Version/s: None
    • Labels:
      None
    • Environment:
      Qt 5.3 on X11

      Description

      Qt 5.3 introduces high-precision touchpad scrolling using XInput2 on X11. This breaks QtQuick's ScrollView and Flickable, however.

      Run the following on X11 using 5.3 Beta

      import QtQuick 2.1
      import QtQuick.Controls 1.0
      import QtQuick.Window 2.0
      
      ApplicationWindow {
          width: 640
          height: 480
      
          ListView {
              anchors.fill: parent
              model: 250
              delegate: Text { text: index }
          }
      }
      

      and then on a notebook do a little bit longer flick. You can also wrap a QtQuick Controls ScrollView around the ListView. It will flick from index 0 to around 200 which is way too much. Even with a ScrollView which doesn't really have momentum, it scrolls to around 50. This works with a traditional Qt widget based applications where the scrolling is precise (does not scroll in deletage-heights but pixel-wise) and stops when lifting off the finger.

      It seems as if the Flickable/ScrollView got the high-precision scroll events (ie. scroll 100 pixels) but interpreted them as mousewheel scroll 3 items per event (resulting in a 300 item scroll)

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              Assignee:
              srutledg Shawn Rutledge
              Reporter:
              broulik Kai Uwe Broulik
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              1 Vote for this issue
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                Created:
                Updated:

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