{}Incorrect screen geometry is calculated when DPI scale is rounded to nearest integer factor.

Issue:

When OS GUI scale factor is set to 125% and Qt's rounding policy is set to "HighDpiScaleFactorRoundingPolicy::Round", the logical screen geometry is still scaled by 1/1.25 before the scale factor is rounded to 1. On a 1920x1080 display, this results in a logical screen geometry of 1536x864 with a scale factor of 1 (see attached "image1.png").

Reproducible:

1) Ensure OS GUI scale is set to 125%

2) Create QMainWindow

3) Set window state to "Qt::WindowFullScreen"

Additional:

Issue also manifests within maximized windows where tooltips extend beyond the logical screen geometry (see attached "image2.png").

Expected:

Behaviour should be commensurate with an OS GUI scale of 1.

Impact:

As Qt does not yield acceptable results when rendering with a fractional scale factor, rounding behaviour is an essential component of modern Qt widget applications.