QT6

[atsju]

Here we go. Fully compatible with Qt5 and Qt6. CI/CD with installer generation for both.
Next release should be named v8.0.0 (no hurry on that).

Build on:

• QT6.8 (LTS) instead QT5
• QWT 6.3.0 instead 6.1.6
• OpenCV4.12.0 instead 4.6.0

Using:

• C++17 instead C++11
• mingw13.1.0 instead 8.1.0

Close #191

[githubdoe]

Nice work. Thank you.

[gr5]

It's great how few changes you had to make. Also I built and ran this in QT5 no problem.

[atsju]

It's great how few changes you had to make.

Great how few incompatible changes are left now yes.
I slowly distilled some minor changes in past 2 years that helped a lot achieving this.