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  1. Qt
  2. QTBUG-93454

No HiDPI scaling on X11 with AA_EnableHighDpiScaling

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Won't Do
    • Affects Version/s: 5.15.2, 6.0.3
    • Fix Version/s: None
    • Component/s: GUI: High-DPI
    • Labels:
      None
    • Platform/s:
      Linux/X11

      Description

      Various applications using Qt set AA_EnableHighDpiScaling on startup, with Qt 6, this is set by default. When using those applications on X11 with a HiDPI monitor, they show up unscaled and are too small to be usable.

      qt.qpa.screen: adding QXcbScreen(0x55c178bd8830, name="Virtual-1", geometry=3840x2160+0+0, availableGeometry=3840x2133+0+0, devicePixelRatio=1.0, logicalDpi=QPair(96.0,96.1), physicalSize=344.0x194.0mm, screenNumber=0, virtualSize=3840x2160 (3840.0x2160.0mm), orientation=Qt::LandscapeOrientation, depth=24, refreshRate=18.4, root=528, windowManagerName="IceWM 2.1.1 (linux-gnu/x86_64)") (Primary: true )
      

      Setting QT_AUTO_SCREEN_SCALE_FACTOR=1 explicitly makes no difference.

      It appears like it's necessary to either override Xft.dpi in the X resources or pass QT_USE_PHYSICAL_DPI=1 now. This was not necessary before Qt 5.14, so this is a regression.

      It seems like the code to detect a HiDPI setup based on physical dimensions was removed without replacement?

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            People

            Assignee:
            sorvig Morten Sørvig
            Reporter:
            vogtinator Fabian Vogt
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              Dates

              Created:
              Updated:
              Resolved:

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