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  1. Qt
  2. QTBUG-86344

Investigate UI rendering at fractional scale factors

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    Details

    • Type: Task
    • Status: In Progress
    • Priority: P2: Important
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: 5.15.3
    • Component/s: GUI: High-DPI
    • Labels:
      None
    • Platform/s:
      All
    • Technical Risk:
      Normal

      Description

      We're looking to make Qt 6 use the native UI scale directly (without rounding), which means that Qt GUIs may be rendered at e.g. 1.25x and 1.75x.

      This change was implemented in https://codereview.qt-project.org/c/qt/qtbase/+/273956 .

      This requires that Qt applications are actually usable at fractional scale factors, and that any visual artifacts are not too jarring. Running at an integer scale factor will give the best visual results, which is something we should consider pointing out in the documentation.

      App developers can enable rounding using  the QGuiApplication::setHighDpiScaleFactorRoundingPolicy() API.

      Test cases:

      • Qt Quick Controls 2 (should be OK)
      • Qt Wigets styles: (examples/widgets/gallery)
        • Fusion style at 1.25x:
      • Some missing frame lines, otherwise OK.
        • Vista style

        Attachments

        1. ce_shapedframe-clip.png
          ce_shapedframe-clip.png
          446 kB
        2. ce_shapedframe-noclip.png
          ce_shapedframe-noclip.png
          453 kB
        3. image-2020-09-16-11-51-35-698.png
          image-2020-09-16-11-51-35-698.png
          1.83 MB
        4. widget-gallery-1.25x.png
          widget-gallery-1.25x.png
          177 kB
        5. widget-gallery-1.25x-downscale.png
          widget-gallery-1.25x-downscale.png
          170 kB
        6. widget-gallery-vista-125x.jpg
          widget-gallery-vista-125x.jpg
          130 kB

          Issue Links

          For Gerrit Dashboard: QTBUG-86344
          # Subject Branch Project Status CR V

            Activity

              People

              Assignee:
              sorvig Morten Sørvig
              Reporter:
              sorvig Morten Sørvig
              Votes:
              2 Vote for this issue
              Watchers:
              8 Start watching this issue

                Dates

                Created:
                Updated: