Display image with Pixel to Pixel accurate no matter what are the scale_factor I setup on 4K display



  • Hi, All,

    Just wonder to know how should I make it possible to display the image with pixel to pixel accurate on QGraphicView on a 4K display on linux. I found that it will default based on the scale factor of system I set to display the picture, for example, if the scale factor is 1.5 and when i display an image with 1000x1000 pixels, I got the result is 1500x1500 pixels which makes the image displayed with alias and not sharp as I want.

    Any parameter I need to setup to use the QGraphicView to display the image correct without the impact of QT_SCALE_FACTOR or QT_AUTO_SCALE_FACTOR.

    btw, I am running on Linux with Qt5.7. Also I see that every image viewer/editor based on Qt/KDE are doing this wrong.

    thanks
    younky



  • Just compile the code on windows 10 which running on Dell XPS 15 with 4K display, the result is perfect. It doesn't zoom the image though I set the scale factor to 2. So this should be a bug of QT, right? Developers should not consider the system difference by using QT to get the same result.


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Each OS has its own way of handling High-DPI which are completely different.

    I'd recommend bringing this question on the interest mailing list. You'll find there Qt's developers/maintainers. This forum is more user oriented.


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