Add modifier key to swap '.' <=> ','

[geroxyz]

Add modifier key to swap decimal separator and group separator ('.' <=> ',') on numeric keyboard. The key can be selected in the extra key preferences.

NOTE: the new version of ./srcs/special_font/result.ttf isn't submitted here, because the creation of this file by make rebuild_special_font
fails on my installation (ubuntu) with

Import: Wrong number of arguments
Called from...
 build.pe: line 10
make: *** [Makefile:26: rebuild_special_font] Fehler 1

So, rebuild result.ttf it on your system, or take the version from my makeshift-resources branch, which is built by adding glyph 0x15 (./srcs/special_font/15.svg) to master version with fontforge manually.

[Julow]

What's the use-case for the modifier key ?

[geroxyz]

If I have to enter a bulk of data in Excel with german keyboard layout
in landscape mode with NumPad, its very convenient, not to swipe for
every numeric input with decimal part.

[geroxyz]

A further issue would be: Activate Swap-Lock on german keybord layout
by default, because that is the standard for german keyboards with 105 keys.

[Julow]

With the comma and dot swapped, you wouldn't have to swipe anymore in Excel. Why isn't the option sufficient ?

What do you mean with Swap-Lock ?

[geroxyz]

When I open Excel with german settings, the keyboard opens as shown below.
In this case, the key right of the numeric 0 should have , as KeyValue by default.
You can achieve this by activating .↔, (SwapLock). Just like Num↓ (NumLock)
on a physical keyboard, which is activated initially.

If this happens at startup, I could even deselect .↔, in the extra key preferences.

[Julow]

Sorry I wasn't clear. An option in the setting that would swap , and . seems more suited than a modifier key. Do you often need to have easier access to the . ? If no, the ability to swap them with a modifier doesn't seem useful.

[geroxyz]

Here some pros for the separator change by modifier key:

• for decimal data in german excel, the , as main KeyValue on the numeric keyboard is best.
  But if you have to enter series of date values (format: 31.12.2024) a quick switch to .
  is convenient.

• on my first approach for the optional NumPad (PR Add optional NumPad #199),
  I had the selection of the separator chars in the settings by having various
  NumPad layouts. But now I prefer the modifier variant, especially when running
  several apps with german settings (as Excel) and apps with english settings
  (programming, graphics) concurrently.
  The way over the keyboard settings is just more cumbersome, and increases
  the amount of setting entries.
  (Btw: On my phone, I prefer portrait mode. But on my tablet, I use landscape with
  optional NumPad very often)

• the concept of modifier keys is used quite often at the unexpected keyboard.
  The difference to other modifiers is, that only the 'locked' state makes sense.
  The 'lock' state, where the modifier is cleared after the first subsequent
  key press is just useless. But that's no obstacle for me.

cons:

• the 'swap' feature is somewhat hidden in the settings. Perhaps its better to move it
  more to the top of 'special keys' settings, or set the modifier visible (and activated?)
  by default for languages with swapped separator signs.

[Julow]

I'd expect date to be typed rarely ? I'm not convinced the swap key is a better solution:

• A new kind of key, working like the numlock key on PC that I personally hate.
• The , and . will change place often. Keys on the keyboard shouldn't move too often. Too much thinking is needed for such a small feature.
• The "pointer" mechanism isn't ready for this new kind of key. It will often reset every modifiers. I'm not willing to spent so much time on fixing it for a relatively small feature.