QTBUG-53022 5.14 will allow fractional devicePixelRatio values. When using OpenGL/Angle this works quite good - some artefacts due to scaling have to accepted.
However using the software renderer now shows some serious rendering problems. Please see the attached screenshots:
- real_application_extract.png shows the effect in a real application (this is only a part of the window).
- example_xxx.png show the effect of the example program with different scale factors. Factor 2.x (200%) is fine.
It looks as if the updated region calculation is also not working correctly with fractional scaling.
With non-fractional scaling this does not seem to be a problem.