QT4 and Vista/Windows 7 High Screen DPI

[ChrisW67]

Hi All,

First a detour through ancient history

I have the dubious honour of maintaining a VB6 application (steam-driven I know). With the imminent arrival of Windows 7 I have had a few users complain of issues with layout breakage, particularly with label text. Not surprising, given the essentially fixed layout of VB6 forms. To see exactly the sort of thing that happens look below. I initially had issues reproducing the corruption but it seems to be the result of Win 7 defaulting to high DPI settings on install (or the user setting them).

Now the stuff we care about...

I've tried a few simple Qt programs with high DPI settings with only mild layout differences but I wonder if anyone here has had experience of Qt's behaviour under these conditions for real-life applications? How well, if at all, does the layout engine cope with the DPI variation? Are there obvious defensive programming approaches that should be used?

I will be rewriting the application in Qt over the coming months, so any collective wisdom could help me avoid these issues repeating.

Regards,
Chris