More column sizing adjustments

[tmiw]

This PR performs the following to address feedback posted at #644 (comment):

1. Limits displayed grid squares to six characters in length and actually ignores invalid input (vs. trying to calculate a distance that's probably wrong).
2. Instead of using wxWidgets' column autosizing, implement our own, ensuring that column sizes don't drop below hardcoded minimums.

[tmiw]

@barjac, hopefully this works for you?

[Tyrbiter]

I built and installed this latest version. There are some issues.

The 2 Mode columns are different widths for some reason. The SNR column is a bit too wide. The Locator column is now wider than the new maximum 6 characters displayed. The distance column could be narrowed a little, 5 digits should be sufficient.

I appreciate how difficult this is, it may also be affected by font sizes.

[barjac]

Yes, here is a direct comparison of before this change and now:

[tmiw]

I fixed the Mode sizing discrepancy and added a change to the sizing calculation that might help. Unfortunately some space does need to be left for the sort indicator, so there might be a limit to how much further the other columns can shrink. For example, when sorting by SNR:

[Tyrbiter]

This seems much better, and apologies for forgetting about the space used by the column sorting indicator.

I don't think much improvement is possible now.

[barjac]

I agree, much improved :)
I have added another screen shot to the group above.
The locator 6 char limiting with case conversion is also working fine. One of our group has upper case last 2 and I noticed the correction this afternoon.

While on the looks of the GUI, could a 'dark mode' be made available from within the program? I can use the system theme in plasma5 on x86_64 but changing the theme in LXQT DE on the RPi4 does not affect FreeDV. Maybe I just can't find the correct setting.

[tmiw]

While on the looks of the GUI, could a 'dark mode' be made available from within the program? I can use the system theme in plasma5 on x86_64 but changing the theme in LXQT DE on the RPi4 does not affect FreeDV. Maybe I just can't find the correct setting.

If you're using wxWidgets 3.2, it should automatically detect the OS/dev environment's setting for that. Seems to on Ubuntu with GNOME, anyway, albeit not 100% perfect. For example, when starting in dark mode:

and then switching to light mode in the GNOME settings:

[tmiw]

BTW, I just checked in a change that should make dark->light mode transitions work a bit better in the FreeDV Reporter window (at least on Linux and maybe macOS; Windows does have some separate logic for that control in wxWidgets so it might not have had the problem in the first place).