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How to enable hi-dpi support on Windows?

  • My app (built with Qt 5.7.1) looks perfect on a Retina MacBookPro. But it looks terrible on a hi-dpi Windows laptop. The fonts and icons are so tiny it is borderline unusable. Apparently the app did not detect the hi-dpi settings on Windows? So how do I fix it? Is it possible? I already turn on Qt::AA_EnableHighDpiScaling for application. Is there anything else I need to do to make the app work on hi-dpi screen under Windows?

    Thank you!

  • Lifetime Qt Champion

    I assume u found

    "While the macOS style fully supports high-DPI, the Windows desktop style currently has some limitations with certain scale factors. In these cases, consider using the Fusion style instead, which aims to support high-DPI in all cases."

    So you could try fiddling with the QT_SCALE_FACTOR
    and see if change anything.

  • Thanks for your reply. But how am I supposed to know what QT_SCALE_FACTOR to set based on user's system settings? I noticed that 'Fusion' style suggestion , too. But to be honest I think it is kind of silly. I want the app to look native on Windows, not in some other 'style'. I'm just a little baffled that at this stage and age (Qt 5.7.1) Qt still can't handle hi-dpi correctly? Really? :-(

  • Lifetime Qt Champion

    No no, just wanted you to play around and see if it can look good at all.
    Qt is using the support of the platform and the result will/might vary.

    Can we see a screen shot on window?

    I wish i could tell you a easy fix but as far as i know there is none.

  • The problem is I don't have a hi-dpi Windows device to test by myself :-( I mainly develop on Mac and everything works well on Mac. I built a Windows version on a low-end PC to let other people use the app on Windows. But quite a few have complained that everything looks too tiny on hi-dpi devices, such as a Surface Pro tablet, or a hi-dpi laptop PC. I don't have a screenshot but I think the problem is clear. My Qt app does not recognize the hi-dpi/scaling settings on Windows. So it renders everything in full/native resolution. That's why the texts and icons look tiny.


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