Split build process to also generate a static library

[cmair]

To be used as a library within other CMake base projects, split the build into a static library and the demo application.
The hub75.hpp file is moved into a new include directory to provide a defined public interface to library users.
Where necessary, relative include paths including the library directory are changed just use the name of the file in question. The specific file will be found via the configured search path.

With those changes, the library can be used within another project by specifying:

# The hub75 library can be found in here
add_subdirectory(
    libraries
)

target_link_libraries(${PROJECT_NAME} hub75)

target_compile_definitions(hub75 PUBLIC
    USE_PICO_GRAPHICS=false      # set to false if you use hub75 as a library - any reference to pico_graphics is removed
    MATRIX_PANEL_WIDTH=64       # your matrix panel width
    MATRIX_PANEL_HEIGHT=32      # your matrix panel height
)

[cmair]

There are a lot of changes and I'm not sure if I got the CMake code right. "It works on my device/project". 😆
Feel free to request changes or discard the PR entirely.

[JuPfu]

Hi Christoph,

I would like to follow your example to make the integration of LVGL more flexible, simpler, and streamlined. You wrote:

For my LVGL integration I'm using a git submodule referencing the 9.3 branch as I prefer having the upstream reference instead of a snapshot This makes it easier to switch between versions, if neccessary. I might explore CMakes FetchContent as well at some point.
Similarly, I'm using the hub75 repository as a git submodule.

I'm going to start by trying this approach with hub75_lvgl to get some initial experience with it.
Do you perhaps have any examples or recommendations for resources or ways to build my knowledge of this functionality ?

Kind regards,
Jürgen

P.S.:

I have now integrated the latest hub75 driver into hub75_lvgl.
Here are two examples of the bounce demo using two daisy-chained 64x64 matrix panels. The panels are from different manufacturers and have different chipsets, so the colors vary slightly. The video quality has been reduced so they can be uploaded here. Colours look much better viewed directly.

hub75_lvgl_9_4_0_chained_2_cols_1_row.mp4

Chained with settings CHAIN_COLS=2 and CHAIN_ROWS=1

hub75_lvgl_9_4_0_chained_1_col_2_rows.mp4

Chained with settings CHAIN_COLS=1 and CHAIN_ROWS=2