The TTF font used by the navigation app is ~20KB and is stored in internal flash memory.
To free this space, the TTF font is now converted in 2 "atlas pictures" (pictures that contain multiple concatenated images) stored in the external flash memory. The navigation app now accesses one of those 2 files and apply an offset to display the desired picture.
The corresponding documentation has also been updated.
Add comments about the layout of the pictures that contain the icon and about the indexing of those icons.
In documentation (buildAndProgram.md), edit the section about the debug compilation mode. Remove the part about removing the Navigation app to free some memory (since it's not relevant anymore) and explain how to selectively build parts of the firmware in Debug mode.
In https://github.com/InfiniTimeOrg/InfiniTime/pull/1097 new font
generation capabilites were added. Generalize the font creation to
make it possible to reuse the `displayapp/fonts/CMakeLists.txt` file
for `InfiniSim` and just add the new cmake file to the project and
link against the new `infinitime_fonts` target.
In the following a list of changes.
Allow non-global installed `lv_font_conv` executable installed with
```sh
npm install lv_font_conv@1.5.2
```
In CMake we search for `lv_font_conv` executable. Add the found
executable to the python script `generate.py`, to remove the need for
`lv_font_conv` to be in the path.
Search for `python3` executable, if CMake version 3.12 is available.
Otherwise use `python` as hard coded executable.
Instead of adding the generated fonts to `SOURCE_FILES` variable, create
a static library `infinitime_fonts`. Link this library to the
executables instead.
Use `add_custom_target()` together with `add_custom_command()` to
generate the font.c files once (like the original PR does).
