Change windows Orientation using C++ code

[keksi venksi]

void MainAppWindow::setLayoutOrientation(int rotate)
{
    // initialize the DEVMODE structure
    DEVMODE dm;
    ZeroMemory(&dm, sizeof(dm));
    dm.dmSize = sizeof(dm);

    // only change first/default display (index=0)
    if (0 != EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm))
    {
       LOG_INFO("Current orientation");
       switch(dm.dmDisplayOrientation)
       {
            case DMDO_DEFAULT:
                LOG_INFO("DMDO_DEFAULT");
                break;
            case DMDO_90:
                LOG_INFO("DMDO_90");
                break;
            case DMDO_180:
                LOG_INFO("DMDO_180");
                break;
            case DMDO_270:
                LOG_INFO("DMDO_270");
                break;
       }


       // Determine the current orientation
       int currentOrientation = dm.dmDisplayOrientation;
       int newOrientation;

       // Set the new orientation
       switch (rotate)
       {
           case 0:
               newOrientation = DMDO_DEFAULT;
               break;
           case 90:
               newOrientation = DMDO_90;
               break;
           case 180:
               newOrientation = DMDO_180;
               break;
           case 270:
               newOrientation = DMDO_270;
               break;
           default:
               LOG_INFO("Something went wrong, aborting");
               return;
       }

       LOG_INFO("Panning height     : " + QString::number(dm.dmPanningHeight) +  " Panning width: " + QString::number(dm.dmPaperWidth) );
       LOG_INFO("Colour resolution  : " + QString::number(dm.dmBitsPerPel) + " bits per pixel");
       LOG_INFO("Height in pixels   : " + QString::number(dm.dmPelsHeight));
       LOG_INFO("Width in pixels    : " + QString::number(dm.dmPelsWidth));

       // parse parameter
       if(rotate != 0 && rotate != 90 && rotate != 180 && rotate != 270)
       {
           LOG_INFO("incorrect rotation selected");
       }
       else
       {

           if ((currentOrientation == DMDO_DEFAULT && newOrientation == DMDO_90) ||
                   (currentOrientation == DMDO_90 && newOrientation == DMDO_DEFAULT) ||
                   (currentOrientation == DMDO_DEFAULT && newOrientation == DMDO_270) ||
                   (currentOrientation == DMDO_270 && newOrientation == DMDO_DEFAULT))
           {
               // swap height and width
               DWORD tmp = dm.dmPelsHeight;
               dm.dmPelsHeight = dm.dmPelsWidth;
               dm.dmPelsWidth = tmp;
           }

         LOG_INFO("Height in pixels after swapping : " + QString::number(dm.dmPelsHeight));
         LOG_INFO("Width in pixels after swapping : " + QString::number(dm.dmPelsWidth));

         // select fields which have changed
         dm.dmFields = DM_PELSWIDTH | DM_PELSHEIGHT | DM_DISPLAYORIENTATION;

         // set angle
         switch(rotate)
         {
             case 0:
                 dm.dmDisplayOrientation = DMDO_DEFAULT;
                 break;
             case 90:
                 dm.dmDisplayOrientation = DMDO_90;
                 break;
             case 180:
                 dm.dmDisplayOrientation = DMDO_180;
                 break;
             case 270:
                 dm.dmDisplayOrientation = DMDO_270;
                 break;
             default:
                 LOG_INFO("Something went wrong, aborting");
                 exit(0);
         }

         LONG ret = ChangeDisplaySettingsEx(NULL, &dm, NULL, 0, NULL); //CDS_RESET, NULL); //0);
         LOG_INFO("ChangeDisplaySettingsEx returned " + QString::number(ret));
         switch(ret)
         {
             case DISP_CHANGE_SUCCESSFUL:
                 LOG_INFO("display successfully changed");
                 break;
             case DISP_CHANGE_BADDUALVIEW:
                 LOG_INFO("The settings change was unsuccessful because the system is DualView capable");
                 break;
             case DISP_CHANGE_BADFLAGS:
                 LOG_INFO("An invalid set of flags was passed in.");
                 break;
             case DISP_CHANGE_BADMODE:
                 LOG_INFO("The graphics mode is not supported.");
                 break;
             case DISP_CHANGE_BADPARAM:
                 LOG_INFO("An invalid parameter was passed in. This can include an invalid flag or combination of flags.");
                 break;
             case DISP_CHANGE_FAILED:
                 LOG_INFO("The display driver failed the specified graphics mode.");
                 break;
             case DISP_CHANGE_NOTUPDATED:
                 LOG_INFO("Unable to write settings to the registry.");
                 break;
             case DISP_CHANGE_RESTART:
                 LOG_INFO("The computer must be restarted for the graphics mode to work.");
                 break;
         }
       }
    }
}

Hi All , I have done the orientation chnage successfully with the above code. I hope it may help some one.

Note : I handled all four possibilties which windows provides -portrait -portrait (flipped) -landscape _landscape (flipped)

we just need to call the method with the respective angle Landscape - 0 Portait - 90 landscape (flipped) - 180 portrait (flipped) - 270

[Pl45m4]

@keksi-venksi

Hi,
nice,
maybe you want to move this topic to the Showcase category as it is not a question or an issue, but already a solution you want to share.

• https://forum.qt.io/category/8/showcase

(Or you wait until some @moderators might move it)