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  4. How can I make my app ignore window's "HIGH DPI SCALING"?
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How can I make my app ignore window's "HIGH DPI SCALING"?

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widgetsdpi awarenessscaling
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  • C Offline
    C Offline
    Curtwagner1984
    wrote on last edited by
    #3

    Thank you! For some reason I assumed this needs to be done after.

    It's like this now:

        QApplication::setAttribute(Qt::AA_DisableHighDpiScaling); // Disable DPI support
    
        QApplication a(argc, argv);
    
    
        MainWindow w;
        w.showMaximized();
        
        return a.exec();
    

    But it doesn't really seem to have an effect.

    This is how it looks on a display with 100% scaling 100 scaling and this is how it looks on a display with 150% scaling 150 scaling

    JKSHJ 1 Reply Last reply
    0
    • C Curtwagner1984

      Thank you! For some reason I assumed this needs to be done after.

      It's like this now:

          QApplication::setAttribute(Qt::AA_DisableHighDpiScaling); // Disable DPI support
      
          QApplication a(argc, argv);
      
      
          MainWindow w;
          w.showMaximized();
          
          return a.exec();
      

      But it doesn't really seem to have an effect.

      This is how it looks on a display with 100% scaling 100 scaling and this is how it looks on a display with 150% scaling 150 scaling

      JKSHJ Offline
      JKSHJ Offline
      JKSH
      Moderators
      wrote on last edited by
      #4

      @Curtwagner1984 said in How can I make my app ignore window's "HIGH DPI SCALING"?:

      it doesn't really seem to have an effect.

      Try running your app in "DPI Unaware" mode: https://doc.qt.io/qt-5/highdpi.html#migrate-existing-applications

      Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

      1 Reply Last reply
      1
      • C Offline
        C Offline
        Curtwagner1984
        wrote on last edited by
        #5

        Thanks,
        I made a file named qt.conf with the line

        <application> -platform windows:dpiawareness=0
        

        And put it in the the folder of the executable. Nothing changed.

        Is this correct? Should application be the name of the application?

        JKSHJ 1 Reply Last reply
        0
        • C Curtwagner1984

          Thanks,
          I made a file named qt.conf with the line

          <application> -platform windows:dpiawareness=0
          

          And put it in the the folder of the executable. Nothing changed.

          Is this correct? Should application be the name of the application?

          JKSHJ Offline
          JKSHJ Offline
          JKSH
          Moderators
          wrote on last edited by
          #6

          @Curtwagner1984 said in How can I make my app ignore window's "HIGH DPI SCALING"?:

          I made a file named qt.conf with the line

          <application> -platform windows:dpiawareness=0
          

          Those are command line arguments. You pass the extra arguments while launching your .exe from the Command Prompt .

          Qt Doc Search for browsers: forum.qt.io/topic/35616/web-browser-extension-for-improved-doc-searches

          1 Reply Last reply
          4
          • C Offline
            C Offline
            Curtwagner1984
            wrote on last edited by
            #7

            Thank you! This works!
            Is there a way to set it up in the application itself, without the need to provide extra command line arguments?

            J.HilkJ 1 Reply Last reply
            0
            • C Curtwagner1984

              Thank you! This works!
              Is there a way to set it up in the application itself, without the need to provide extra command line arguments?

              J.HilkJ Offline
              J.HilkJ Offline
              J.Hilk
              Moderators
              wrote on last edited by
              #8

              @Curtwagner1984
              good old putenv, probably

              https://www.cprogramming.com/fod/putenv.html


              Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


              Q: What's that?
              A: It's blue light.
              Q: What does it do?
              A: It turns blue.

              JonBJ 1 Reply Last reply
              0
              • J.HilkJ J.Hilk

                @Curtwagner1984
                good old putenv, probably

                https://www.cprogramming.com/fod/putenv.html

                JonBJ Offline
                JonBJ Offline
                JonB
                wrote on last edited by
                #9

                @J-Hilk
                I looked at this. What environment variable name (and value) are you proposing for -platform windows:dpiawareness=0, I could not see that it worked this way??

                J.HilkJ 1 Reply Last reply
                0
                • JonBJ JonB

                  @J-Hilk
                  I looked at this. What environment variable name (and value) are you proposing for -platform windows:dpiawareness=0, I could not see that it worked this way??

                  J.HilkJ Offline
                  J.HilkJ Offline
                  J.Hilk
                  Moderators
                  wrote on last edited by J.Hilk
                  #10

                  @JonB admittedly
                  the official way to do it, is apparently the creation and deployment of a qt.conf file, same level as the executable with this content:

                  [Platforms]
                  WindowsArguments = dpiawareness=0

                  that said:

                  qputenv("dpiawareness", "0"); or qputenv("windows:dpiawareness", "0");

                  I'm unsure, I'm not using it often enough :D


                  Be aware of the Qt Code of Conduct, when posting : https://forum.qt.io/topic/113070/qt-code-of-conduct


                  Q: What's that?
                  A: It's blue light.
                  Q: What does it do?
                  A: It turns blue.

                  JonBJ C 2 Replies Last reply
                  2
                  • J.HilkJ J.Hilk

                    @JonB admittedly
                    the official way to do it, is apparently the creation and deployment of a qt.conf file, same level as the executable with this content:

                    [Platforms]
                    WindowsArguments = dpiawareness=0

                    that said:

                    qputenv("dpiawareness", "0"); or qputenv("windows:dpiawareness", "0");

                    I'm unsure, I'm not using it often enough :D

                    JonBJ Offline
                    JonBJ Offline
                    JonB
                    wrote on last edited by JonB
                    #11

                    @J-Hilk said in How can I make my app ignore window's "HIGH DPI SCALING"?:

                    qputenv("dpiawareness", "0"); or qputenv("windows:dpiawareness", "0");
                    I'm unsure, I'm not using it often enough :D

                    There is/I can see no evidence that a Qt program would recognise either of these proposed environment variable names. Unless you can see where it says it does.... I see only the command line or qt.conf file approaches so far.

                    1 Reply Last reply
                    0
                    • J.HilkJ J.Hilk

                      @JonB admittedly
                      the official way to do it, is apparently the creation and deployment of a qt.conf file, same level as the executable with this content:

                      [Platforms]
                      WindowsArguments = dpiawareness=0

                      that said:

                      qputenv("dpiawareness", "0"); or qputenv("windows:dpiawareness", "0");

                      I'm unsure, I'm not using it often enough :D

                      C Offline
                      C Offline
                      Curtwagner1984
                      wrote on last edited by
                      #12

                      @J-Hilk said in How can I make my app ignore window's "HIGH DPI SCALING"?:

                      [Platforms]
                      WindowsArguments = dpiawareness=0

                      Thank you! I tried to used this before but I've put incorrect syntax in this file. This works.

                      1 Reply Last reply
                      2
                      • A Offline
                        A Offline
                        arunkannan
                        wrote on last edited by
                        #13

                        @Curtwagner1984 @JonB @J-Hilk @JKSH
                        I used Python PyQt5-5.15 for my application
                        I have guimain.exe and panelgui.ui files . Made qt.conf file
                        But when I change windows scaling to 125% or 150% the text fonts and other ui widgets get messed up...how to make it work i.e disable windows scaling for application

                        1 Reply Last reply
                        0
                        • V Offline
                          V Offline
                          Violet Giraffe
                          wrote on last edited by Violet Giraffe
                          #14

                          In Qt 6 you can override the scale factor with the QT_SCALE_FACTOR env variable, but there is a problem: it doesn't set the factor to your value, it multiplies it. For example, if the system has 150% and you want 100%, you need to set QT_SCALE_FACTOR to 0.666667 (and even then it might not end up exactly 1.0 but rather 1.0001).

                          Is this intentional? There is a number of problems resulting from this multiplicative behavior, the primary one being when the application is moved between screens with different scale factors. I want to have 1.0 everywhere, not 0.66!

                          Also, -platform windows:dpiawareness=0 DOES NOT WORK!
                          Or, rather, it does the wrong thing. It disables too much, devicePixelRatio() reports 1.0 but the window is stretched and blurry.

                          1 Reply Last reply
                          0
                          • V Offline
                            V Offline
                            Violet Giraffe
                            wrote on last edited by
                            #15

                            Found the proper option: QT_ENABLE_HIGHDPI_SCALING=0.

                            1 Reply Last reply
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