Uploaded image for project: 'Qt'
  1. Qt
  2. QTBUG-99613

Accessible delegates slowing QML Gridview scrolling in static Qt

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Reported
    • Priority: P3: Somewhat important
    • Resolution: Unresolved
    • Affects Version/s: 5.15
    • Fix Version/s: None
    • Labels:
      None
    • Platform/s:
      macOS

      Description

      When running Qt that is statically linked, a simple GridView with accessible delegates becomes significantly slower on scrolling. This is not noticeable in dynamically linked qt. 
      This has been seen with static QT5.15.6 and QT 5.15.7 versions so far.

      QML profiling gives the following after scrolling 60000 identical items in a gridview, the creation of the text visibly lags the grid view scrolling when there is accessibility in the delegate.

      Accessibility Type Details Total Time Mean Time Calls
      Yes Creating QtQuick/Text  12.9s  614 µs 21034
      No Creating  QtQuick/Text  438ms  14.4 µs 30488

      Here is the QML code that was profiled (the accessibility was commented out for the one without accessibility)

      import QtQuick 2.15
      import QtQml 2.15
      import QtQuick.Controls 2.15
      
      ApplicationWindow {
          width: 640
          height: 480
          visible: true
      
              GridView {
                  id: root
      
                  model: 60000
                  anchors.fill: parent
      
                  cellWidth: 180
                  cellHeight: 30
      
                  delegate: Text {
                       text: "Text"
                       color: "black"
                       Accessible.role: Accessible.Button
                       Accessible.name: "Text"
                       Accessible.selected: false
                       Accessible.selectable: true
                       Accessible.focusable: true
                  }
      
                  reuseItems: true
                  clip:true
              }
      }
      

       

        Attachments

        No reviews matched the request. Check your Options in the drop-down menu of this sections header.

          Activity

            People

            Assignee:
            qt.team.quick.subscriptions Qt Quick and Widgets Team
            Reporter:
            joecresswell Joseph Cresswell
            Votes:
            2 Vote for this issue
            Watchers:
            3 Start watching this issue

              Dates

              Created:
              Updated:

                Gerrit Reviews

                There are no open Gerrit changes